Weight Loss
Exercise and Weight Loss featured article
Aerobic exercise has many health benefits: It keeps the heart's structure youthful, it increases mitochondria, and it reduces our long-term risk of cognitive decline and other neurodegenerative conditions. That's just to name a few.
Exercise is also promoted widely as a strategy for weight loss—often in combination with dietary changes—as it increases total daily energy expenditure and creates an energy deficit.
While 150 minutes per week of moderate-intensity exercise is recommended for general health, higher doses (200–300 minutes per week) are typically required to achieve significant weight loss in individuals with overweight or obesity. However, the weight loss achieved through exercise alone, even at higher doses, is often less than expected. Why? This discrepancy is due to several interrelated mechanisms involving dietary intake, behavioral adaptations, and physiological compensation.
- Increased appetite: Exercise frequently stimulates appetite, leading to...
Episodes
In this clip, Dr. Ben Bikman explores GLP-1 drugs like Ozempic, highlighting dosing strategies, hidden risks, and their potential beyond...
In this Aliquot, I discuss how these drugs work, their pros and cons, the latest research, and lifestyle strategies to...
In this clip, Drs. Rhonda Patrick and Layne Norton discuss calorie tracking, weight-loss self-deception, and misconceptions about metabolism and food.
-
In this clip, Dr. Ben Bikman explores GLP-1 drugs like Ozempic, highlighting dosing strategies, hidden risks, and their potential beyond...
-
In this Aliquot, I discuss how these drugs work, their pros and cons, the latest research, and lifestyle strategies to...
-
In this clip, Drs. Rhonda Patrick and Layne Norton discuss calorie tracking, weight-loss self-deception, and misconceptions about metabolism and food.
-
Dr. Rhonda Patrick discusses GLP-1 agonists, alpha-lipoic acid, ubiquinone vs. ubiquinol, calcium needs, and liquid biopsy cancer screening.
-
This Soda Hack Helps You Lose Weight Without the Cancer Risk (but will it wreck your microbiome?) ClipIn this clip, Dr. Layne Norton discusses diet soda, weight loss, artificial sweeteners, insulin, microbiome, and health risks.
-
In this clip, Dr. Rhonda Patrick explores Ozempic, covering appetite reduction, weight maintenance, muscle loss, efficacy, and side effects.
-
Exercise Nutrition Obesity Metabolism Muscle Polyunsaturated Fat Saturated Fat Time-Restricted Eating Protein Weight Loss Strength SupplementsDr. Layne Norton and I discuss fat loss, resistance training, seed oils, the carnivore diet, artificial sweeteners, and much more.
-
In this clip, Dr. Martin Gibala discusses the 'afterburn effect' and its impact on post-workout metabolism.
-
Rhonda Nutrition Parkinson's Microbiome Omega-3 Sulforaphane Sauna Weight Loss Intestinal Permeability CocoaDr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.
-
In this clip, Dr. Dominic D'Agostino outlines the advantages and disadvantages of various ways of quantifying ketosis.
-
In this clip, Dr. Dominic D'Agostino describes how breath acetone concentration is a non-invasive tool for measuring fat loss.
-
Rhonda Vitamin D Exercise Obesity Vitamin C Pregnancy Muscle Sulforaphane Sauna Time-Restricted Eating Blood Sugar Weight Loss NAD+Dr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.
-
Dr. Rhonda Patrick describes the effects of endogenous ketones on fat metabolism during a fast.
-
Dr. Ruth Patterson discusses the beneficial effects that time-restricted eating can have on the biomarkers of health - independent of weight loss.
-
Rhonda Vitamin D Brain Alzheimer's Gut Microbiome Sleep Fasting Autophagy Sauna Vegetarian Weight Loss Supplements Ketogenic Diet Wearable Technology Blood TestDr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.
Topic Pages
-
Exercise and Weight Loss
Weight Loss and Exercise elevates energy expenditure and fat oxidation, establishing a caloric deficit that mechanistically produces subsequent Weight Loss.
News & Publications
-
GLP-1 receptor agonist weight-loss drugs such as semaglutide may protect the cardiovascular system independent of weight loss. https://doi.org/10.1016/ S0140-6736(25)01375-3
Doctors have long wondered whether the heart benefits of the GLP-1 receptor agonist semaglutide (Ozempic®/Wegovy®) come mainly from helping people lose weight, or if the drug directly protects the cardiovascular system. The SELECT trial explored this question in adults with established heart disease and overweight or obesity, but without diabetes, testing whether changes in body fat could explain the drug's effects. The SELECT trial explored this question in adults with atherosclerotic cardiovascular disease and overweight or obesity, but without diabetes.
The study followed 17,604 participants aged 45 years or older across 41 countries. Each person was randomly assigned to once‑weekly semaglutide with dose escalation to a 2.4 mg target or placebo and followed for an average of more than three years. Researchers repeatedly measured heart attacks, strokes, and cardiovascular deaths (collectively known as major adverse cardiovascular events, or MACE) as well as weight and waist circumference.
Here is what the team found:
- Semaglutide lowered the risk of major adverse cardiovascular events by about 20 percent versus placebo, and the benefit appeared early within the first 20 weeks.
- The treatment effect was consistent across baseline body size measures including weight, BMI and waist circumference.
- Early weight loss at 20 weeks did not predict lower subsequent MACE among those taking semaglutide; people who lost at least 5 percent had similar event rates to those who lost less.
- In contrast, reductions in waist circumference at 20 weeks were associated with fewer subsequent events in the semaglutide group, possibly highlighting the importance of visceral fat loss (fat surrounding abdominal organs) rather than overall weight loss, which can also include lean mass such as muscle.
- Statistical modeling estimated that about one‑third of the treatment effect on MACE was mediated or marked by waist‑circumference reduction, while the remaining two-thirds came from other factors.
- In the placebo group, those with at least 5 percent weight loss at 20 weeks had higher mortality than those with smaller losses or weight gain, possibly because their weight loss reflected underlying illness rather than improved health.
The researchers suggest that semaglutide's heart protection likely extends beyond weight or fat loss. By activating the glucagon-like peptide-1 receptor, the drug may directly influence blood vessel function, atherosclerotic processes, inflammation, blood pressure, and lipid metabolism. The authors also note that adipose tissue can begin to change biologically before its overall mass declines, which might help explain the early cardiovascular benefits seen in the trial.
These results have major implications for treatment and policy. They show that patients with cardiovascular disease may benefit from semaglutide regardless of how much weight they lose, challenging prescribing rules that rely on body mass index thresholds or weight-loss targets. The authors call for future studies to identify which biological processes drive these early improvements and to determine whether similar benefits apply to broader populations. In Aliquot #128, I discuss how the new weight loss drugs like Ozempic® and Mounjaro® work, their pros and cons, the latest research, and lifestyle strategies to optimize their effects for long-term health.
-
Childhood obesity is a growing concern with multiple contributing factors, and perhaps, exposure to artificial light at night is among the most important. To investigate this, researchers in China followed more than 218,000 schoolchildren over a 15-year period.
Each year, the students underwent health examinations that included body mass index measurements. At the same time, satellite data provided yearly measurements of how bright the outdoor night sky was in the area around each school. Children were then grouped based on long-term trends over the study period: areas that stayed consistently bright, areas that brightened slowly, areas that brightened rapidly, and areas where brightness declined. Because the rapidly brightening pattern had the lowest baseline light, it served as the reference group for all comparisons.
The study revealed distinct differences across the light exposure groups:
- Children attending schools in areas that stayed consistently bright had the highest risk. Boys had a 67% higher rate of becoming overweight or obese, and girls had a 56% higher rate.
- In areas that brightened slowly, the risk was elevated but not statistically significant.
- Areas where brightness declined showed no meaningful difference from the reference.
- Among children who began at a normal or low weight, the consistently bright group recorded 9.95 new cases of overweight or obesity per 1,000 person-years, compared with 6.10 in the rapidly brightening group and 8.04 in the slowly brightening group.
- On a population level, long-term exposure to consistently bright night-time environments accounted for about 40 percent of the risk in boys and 36 percent in girls.
Prolonged exposure to artificial light disrupts circadian rhythms, the internal clocks that regulate daily cycles of hormones such as melatonin and cortisol. When these rhythms are disturbed, appetite, metabolism, and fat storage can be affected in ways that promote weight gain. Another possible mechanism may involve brown fat, a tissue that normally burns energy to generate heat but may become less active under constant night-time light. The differences between boys and girls may reflect a mix of biological sensitivity and behavioral factors such as screen use. Finally, the stronger risks in the consistently bright and slowly brightening groups may point to the impact of longer cumulative exposure, whereas more recent increases in brightness, as in the rapidly brightening group, may not have had the same effect.
Conclusion:
Children who attended schools in brighter night-time environments were more likely to gain excess weight over the school years. The study was limited because light levels were estimated from school locations, not individual homes, and detailed information on diet, activity, or puberty was unavailable. Moreover, while the analysis adjusted for broad regional differences, it cannot be ruled out that environmental and socioeconomic changes occurring alongside rising night-time light influenced the results. Still, the findings highlight night-time light as a potential and under-recognized factor in childhood overweight and obesity. Learn more about how to improve sleep in episode #45 featuring Dr. Matthew Walker. -
Adolescent obesity often persists into adulthood and raises cardiometabolic risks, but altering the gut microbiome may help shift long-term health trajectories. Researchers tested whether taking capsules containing gut microbes from healthy donors during adolescence could leave durable clinical and microbiome changes years later.
Researchers followed up on a previous trial where adolescents received either gut microbiota from healthy lean adults or a placebo. About four years later, 55 participants returned for assessment. The team measured body composition, metabolic markers, and gut microbial and viral profiles using DNA sequencing.
At the four year visit, several cardiometabolic and body composition measures favored the transplant group:
- Waist circumference was 10 cm lower in the fecal transplant group.
- Total body fat percentage was 4.8 points lower.
- A metabolic syndrome severity score was lower.
- The inflammation marker hs-CRP was 68 percent lower.
- HDL cholesterol was 0.16 mmol per liter higher.
These health differences were accompanied by lasting shifts in the gut microbiome. Adolescents who received donor microbes had a more diverse and markedly reshaped gut microbiome compared with placebo. Signatures of donor bacteria could still be detected years later, and participants who took up more donor strains soon after treatment tended to retain more of them long term. The gut bacteriophages – viruses that infect bacteria – also showed lasting donor patterns. Some of these microbial and viral differences were linked with healthier metabolic scores and weight change, although these links cannot prove cause and effect.
Conclusion:
A single course of oral fecal microbiota transplant during adolescence was followed by lower central adiposity and body fat, lower systemic inflammation, and a better composite metabolic risk score about four years later, while BMI remained similar. However, it's important to mention that BMI is a limited measure because it doesn't distinguish between fat and lean mass and can therefore miss meaningful shifts in fat distribution. The gut microbiome continued to show donor traits, which might help explain the observed health effects. However, the study has limitations: it was unblinded, had high dropout rates, didn't track medication or lifestyle changes continuously, and used a statistical approach that may increase false positives. Overall, the results are promising, but they warrant cautious interpretation and further confirmation. Learn more about the microbiome in episode #70 featuring Dr. Eran Elinav. -
Fat oxidation, the process of breaking down fatty acids from both stored and dietary fat for energy, is critical for endurance during physical activity and weight control. However, not everyone's body uses fat efficiently during activity. In search of contributing factors, researchers investigated whether low vitamin C levels reduce fat burning.
The study involved healthy young adults with either marginal or adequate vitamin C status. Participants completed a one-hour treadmill session at submaximal intensity while researchers measured fat oxidation. In a follow-up experiment, participants with low vitamin C levels were randomly assigned to take either 500 milligrams of vitamin C per day or a placebo for four weeks, after which the exercise test was repeated.
Vitamin C status showed effects on increasing fat burning:
- Participants with marginal vitamin C status used roughly one-quarter less fat for energy during exercise, relative to those with adequate status.
- Lower fat oxidation was linked to higher self-reported fatigue.
- Among deficient participants, vitamin C supplementation increased fat-derived energy expenditure during exercise four-fold compared to placebo.
- Plasma carnitine differed by vitamin C status and was related to fat oxidation during exercise. Carnitine helps shuttle fatty acids into mitochondria to be broken down for energy.
These findings are consistent with vitamin C's role in producing carnitine. Without enough vitamin C, carnitine synthesis may falter, reducing the transport of fatty acids for oxidation. This bottleneck could increase reliance on carbohydrate stores and contribute to fatigue during exercise.
Conclusion:
The study suggests that low vitamin C status is associated with reduced fat oxidation and greater fatigue during submaximal physical activity, and that supplementation can improve fat metabolism. Beyond its impact on exercise performance, the combination of reduced fat oxidation and increased fatigue could also contribute to weight gain, both by discouraging regular, demanding physical activity and by favoring fat storage. Although the results are intriguing, the study was small and did not directly measure muscle carnitine. Larger, more comprehensive studies are needed to confirm these findings. Learn more about how inadequate micronutrient levels impact health in this clip featuring Dr. Bruce Ames. -
Time-restricted eating helps lose weight without compromising sleep, mood, or quality of life, regardless of when the eating window occurs. jamanetwork.com
Meal timing may influence more than just hunger—it can affect our sleep, mood, and day-to-day functioning. Time-restricted eating, a strategy that limits food intake to a specific window each day, has shown promise for weight loss and improved metabolic health, and may also support other aspects of well-being. A recent study found that people who followed time-restricted eating lost about 3 kilograms (roughly 6.5 pounds) more than those who didn't, regardless of whether they ate early, late, or chose their own schedule.
Researchers provided 197 adults who had overweight or obesity with guidance on following a Mediterranean-style diet. Then, they assigned some of the participants to one of three schedules: an early time-restricted eating schedule (starting before 10 a.m.), a late schedule (starting after 1 p.m.), or a self-selected 8-hour eating window. The remainder followed a typical daily eating pattern. The researchers measured the participants' sleep with wearable devices and assessed mood and quality of life through standard questionnaires before and after the intervention.
They found no meaningful differences between the groups in total sleep time, stress, depression, anxiety, or general quality of life. For example, sleep duration differed by only about 12 minutes across groups, and mood scores remained stable. There were also no marked differences between early, late, and self-selected eating windows.
These findings suggest that incorporating time-restricted eating into a weight loss program is unlikely to harm sleep, mood, or quality of life, regardless of the time of day the eating window falls. Evidence suggests time-restricted eating offers a wide range of health benefits. Learn more in this clip featuring Dr. Satchin Panda.
-
Alternate-day fasting, a form of intermittent fasting that involves alternating days of little or no food intake with days of unrestricted eating, may provide a slight yet meaningful advantage over other diet strategies for weight loss and improving some heart health markers. A recent review found that people following an alternate-day fasting plan lost about 1.3 to 1.7 kilograms (3 to 4 pounds) more than those practicing time-restricted eating, whole-day fasting, or traditional calorie-cutting diets.
Researchers conducted a systematic review and meta-analysis of 99 randomized clinical trials comparing three types of intermittent fasting—alternate day fasting, time-restricted eating, and whole-day fasting—with continuous calorie restriction and unrestricted (ad libitum) diets. Outcomes included weight, blood pressure, cholesterol levels, blood glucose control, inflammation, and markers of liver function.
All forms of intermittent fasting and calorie restriction promoted weight loss compared to unrestricted eating. Alternate-day fasting resulted in slightly more weight loss than the other fasting methods but also modestly lowered total cholesterol, triglycerides, and non-HDL cholesterol compared to time-restricted eating. These benefits were most apparent in studies lasting less than about six months. None of the fasting methods outperformed calorie restriction for improving blood glucose or HDL cholesterol levels.
These findings suggest that intermittent fasting, especially alternate-day fasting, can be just as effective as calorie restriction for managing weight and improving some cardiometabolic risk factors. Intermittent fasting may extend lifespan, too. Learn more in this clip featuring Dr. Mark Mattson.
-
Weighted vests may mitigate metabolic slowdown and subsequent weight regain in older adults after diet-induced weight loss, according to a pilot study. pubmed.ncbi.nlm.nih.gov
Although many older adults can successfully lose weight through diet and exercise, most eventually regain it, partly due to changes in metabolism and appetite that happen after weight loss. However, gravitational loading—the physical force the body applies during movement—may have a surprising influence on long-term weight management. A recent study found that older adults who wore a weighted vest during a six-month weight loss program were less likely to regain the weight they lost, possibly because their metabolism remained more stable.
Researchers enrolled 18 older adults with obesity in a six-month weight loss program that included daily calorie restriction. Half of the participants also wore a weighted vest (weighing a minimum of 10 pounds) for 10 hours daily. The researchers measured the participants' body weight and resting metabolic rate before and after the six-month intervention, and again at 24 months.
Both groups lost about the same amount of weight by six months—roughly 11% of their starting weight. But 24 months later, those who wore the weighted vest had kept off about half the weight they had lost, while the others had regained nearly all of it. Participants who wore the vest also showed far less decline in their resting metabolic rate—less than 20 calories per day—compared to a drop of more than 230 calories per day in the diet-only group. Those with greater drops in metabolic rate were more likely to regain weight.
These findings suggest that wearing a weighted vest during weight loss helps older adults sustain their results, possibly by reducing the metabolic slowdown that usually follows weight loss. Although this was a small pilot study, the results support the idea that gravitational loading can affect long-term weight management and may provide a new strategy for preventing weight regain.
-
Artificial sweeteners like sucralose are marketed as healthier alternatives to sugar, but they may send mixed signals to the brain. A recent study found that sucralose increased hunger and altered activity in the part of the brain that regulates appetite, with effects differing by body weight.
Researchers asked 75 young adults—some with a healthy weight and some with overweight or obesity—to drink a beverage sweetened with either sucralose (often marketed as Splenda), sucrose (table sugar), or plain water on three separate occasions. Afterward, the researchers measured the participants' blood glucose levels, collected their self-reported hunger ratings, and conducted brain scans to examine activity and connectivity in key regions involved in appetite control.
Compared to sugar, sucralose increased blood flow to the hypothalamus and promoted stronger feelings of hunger. Sucralose also heightened hypothalamic activity more than water but didn’t influence hunger. Only sugar elevated blood glucose levels, an increase linked to reduced activity in the hunger-regulating regions of the brain.
Interestingly, the brain’s response to sucralose differed based on body weight: In people with a healthy weight, sucralose enhanced connections between the hypothalamus and areas involved in attention and decision-making. In those with overweight, sucralose diminished connections to brain regions that process bodily sensations. And those with obesity exhibited little to no change in these neural connections. Compared to water, both sweeteners elicited distinct patterns of brain activity depending on weight status.
These findings suggest that sucralose interferes with the brain’s normal appetite-regulating signals by mimicking sweetness without delivering the expected rise in blood sugar. This mismatch appears to increase hunger and alter brain connectivity in ways that vary depending on body weight. Artificial sweeteners also affect the gut microbiome. Learn more in this clip featuring Dr. Eran Elinav.
-
Omega-3 supplementation combined with exercise improves body composition and cardiometabolic health more effectively than exercise alone, including a notable 10% decrease in triglyceride levels. pubmed.ncbi.nlm.nih.gov
Taking an omega-3 supplement may do more than support heart health—it might enhance the effects of your workout. A recent study found that combining omega-3 supplementation with exercise training improved body composition and cardiometabolic health better than exercise alone.
Researchers conducted a systematic review and meta-analysis of 21 studies comparing exercise training combined with omega-3 supplementation to exercise training alone. The studies involved 673 adults aged 30 to 70, with an average body mass index (BMI) of 24 to 37. The analysis focused on outcomes such as body fat, blood pressure, blood fats, blood sugar, inflammation, and muscle mass, while accounting for variations across the studies.
They found that adding omega-3 supplements to an exercise routine resulted in modest improvements. Participants lost just over 1 kilogram (2.3 pounds) more body fat and lowered their triglyceride levels by 10% compared to those who exercised without supplements. They also experienced drops in blood pressure—around 4 mmHg lower for both systolic and diastolic pressures—and slightly reduced levels of tumor necrosis factor-alpha, a marker of inflammation. However, LDL cholesterol increased slightly. Notably, participants also improved their lower-body strength but observed no additional benefits in other areas such as BMI, lean body mass, or blood glucose control.
These findings indicate that omega-3 supplements enhance certain health benefits of exercise, particularly in decreasing fat mass, lowering blood pressure, and boosting muscle strength. Although the changes were modest, they could accumulate over time, especially for adults aiming to improve their cardiometabolic health. Some evidence suggests that omega-3s exert anabolic effects, too. Learn more in this episode featuring Dr. Chris McGlory.
-
Intermittent fasting three nonconsecutive days per week coupled with regular exercise promotes more weight loss than daily calorie restriction. www.acpjournals.org
Diets that require daily calorie cutting are hard to adhere to, and most people gain the weight back within a year. Intermittent fasting, which involves eating very little on some days and freely on others, might offer a more sustainable alternative. A recent study found that fasting three nonconsecutive days per week promoted more weight loss than daily calorie restriction as part of a comprehensive weight loss program.
Researchers assigned 165 adults aged 18 to 60 with a body mass index between 27 and 46 to one of two diet plans. One group followed a 4:3 intermittent fasting schedule, eating freely on four days of the week and cutting calories by 80% on three nonconsecutive days each week. The second group followed a daily calorie restriction (about 34% less than baseline needs) to match the same total weekly calorie reduction. Both groups also participated in a year-long behavioral weight loss program that included group support and a goal of 300 minutes of moderate exercise weekly.
After 12 months, participants in the intermittent fasting group lost roughly 6.4 pounds more, on average, than those in the daily calorie restriction group. Just over three-fourths of participants completed the study. The difference in weight loss between the two groups was small but statistically meaningful.
These findings suggest that intermittent fasting offers a modest advantage over daily calorie restriction for people trying to lose weight, especially when paired with regular exercise and behavioral support. Learn more about the health benefits of intermittent fasting in this clip featuring Dr. Mark Mattson.
-
GLP-1 receptor agonists may lower risks for major illnesses like dementia and seizures. www.nature.com
Ozempic, Wegovy, and other glucagon-like peptide-1 (GLP-1) drugs have catapulted into the mainstream of diabetes care, with more than 15 million people in the U.S. currently taking one. Evidence suggests GLP-1 drugs have many off-target effects—both good and bad—but healthcare providers don’t currently know the full extent of the drugs' effects. However, a recent analysis found that GLP-1s may reduce the risk of dementia, seizures, respiratory illnesses, cardiometabolic disorders, and certain infections more effectively than other diabetes drugs and typical care.
Using the U.S. Department of Veterans Affairs healthcare databases, researchers identified roughly two million people with diabetes who were using a GLP-1 drug, one of three common anti-diabetes drugs (sulfonylureas, DPP4 inhibitors, or SGLT2 inhibitors), or continuing their usual care without adding new therapies. They tracked the participants' health for about 3.6 years.
They found that GLP-1 use was associated with a reduced risk of dementia (8%), seizures (10%), respiratory illnesses (10% to 25%), cardiometabolic disorders (7% to 22%), and certain infections (12% to 25%). However, the drugs were associated with an increased risk of gastrointestinal issues (5% to 20%), low blood pressure (10%), kidney problems (10% to 15%), arthritic disorders (10% to 16%), and pancreatitis (15% to 20%).
These findings suggest that GLP-1 receptor agonists offer promising benefits for people with diabetes while highlighting potential risks. Further research will illuminate the full range of the drugs' effects. Learn more about GLP-1 drugs in this clip featuring Dr. Rhonda Patrick.
-
High-protein, low-calorie diets—whether animal or plant-based—lead to an average weight loss of ~18 pounds and improved glucose metabolism in people at risk for type 2 diabetes. dom-pubs.pericles-prod.literatumonline.com
The global obesity epidemic is driving a marked increase in the incidence of type 2 diabetes, and some experts estimate that by 2024, more than 780 million adults worldwide will develop the disease. A recent study found that high-protein, low-calorie diets promote weight loss and improve cardiometabolic markers in people at risk for type 2 diabetes.
The study involved 117 adults with either prediabetes or type 2 diabetes and a body mass index (BMI) over 27.5—considered overweight or obese. Participants consumed an animal- or plant-based high-protein diet that provided 35% of their total calories for six months. The remainder of their calories came from fat (30%) and carbohydrates (35%).
Participants in both groups saw similar improvements in body composition, including an average weight loss of approximately 8 kilograms (~18 pounds) and reduced visceral (abdominal) fat. Glucose metabolism indicators, such as fasting glucose and glycated hemoglobin levels, improved equally in both groups, as did lipid levels, liver enzymes, and inflammatory markers.
These findings suggest that high-protein, low-calorie diets—whether animal- or plant-based—can improve body composition, glucose metabolism, and other cardiometabolic markers in people with prediabetes or type 2 diabetes.
Dietary protein supports muscle hypertrophy and maintenance—critical aspects of glucose metabolism. Learn how to optimize protein intake to support muscle health when following a plant-based diet in this clip featuring Dr. Luc van Loon.
-
With millions worldwide affected by obesity-linked conditions like diabetes and cardiovascular disease, understanding which dietary methods are most effective has become crucial. A recent review and meta-analysis found that fasting-based strategies are slightly more effective for promoting weight loss and improving insulin sensitivity than calorie restriction.
Researchers reviewed 10 randomized controlled trials involving more than 600 participants to compare the effects of fasting-based and calorie-restricted diets on weight loss and metabolic health. Fasting-based strategies included intermittent fasting, time-restricted eating, and alternate-day fasting, while continuous calorie restriction involved reducing daily caloric intake by 20% to 40% without meal timing changes.
They found that both methods effectively reduced body weight, with participants losing around 5.5 to 6.5 kilograms (roughly 12 to 14 pounds) after six months. Fasting-based approaches had a slight edge in short-term weight and fat loss—about 1 kilogram (2.2 pounds) more than calorie restriction—but both approaches had similar effects on lean body mass, waist and hip circumference, blood pressure, lipid levels, and glucose metabolism. Notably, fasting-based methods also lowered fasting insulin levels and improved insulin sensitivity.
These findings suggest that while both methods support weight loss, fasting-based diets may offer additional short-term metabolic benefits. Learn more about fasting-based diets and calorie restriction from these great resources:
What type of fasting is best? Caloric restriction vs. periodic fasting and the importance of re-feeding after a fast The link between sirtuins, calorie restriction, fasting, and the insulin pathway Topic article: Fasting
-
Lifestyle interventions that focus on diet, exercise, and weight management reduce the risk of diabetes—despite underlying genetic risk. pubmed.ncbi.nlm.nih.gov
Although a person’s genes play a pivotal role in whether they develop diabetes, lifestyle factors—like diet, exercise, and body weight—influence their risk, too. A recent study found that lifestyle interventions reduce the risk of developing diabetes, especially among those at high genetic risk.
The study involved nearly 1,000 middle-aged men with metabolic syndrome—a constellation of health conditions that increases the for diabetes. About half of the men had a low genetic risk for the disease, while the remainder had a high genetic risk. The men participated in a three-year-long group-based lifestyle intervention program that involved dietary counseling, exercise guidance, and weight management. Researchers monitored the men’s health and diabetes incidence throughout the study period.
They found that the intervention reduced the risk of developing diabetes by 70% among participants with high genetic risk and 31% among those with low genetic risk. However, the latter reduction wasn’t statistically significant. The intervention promoted weight loss and prevented increased blood glucose levels in both groups.
These findings suggest that lifestyle interventions can have marked effects on diabetes incidence in people at risk. Exercise, in particular, makes the body’s tissues more sensitive to insulin, helping to maintain healthy blood glucose levels. Learn more about how exercise may prevent diabetes in this episode featuring Dr. Guido Kroemer.
-
Appetite control varies widely with different weight-loss interventions. onlinelibrary.wiley.com
The body’s appetite feedback circuit is a sophisticated system that regulates hunger and satiety to maintain energy balance. Suppressing this circuit is essential to successful weight loss before reaching a plateau. A recent study found that weight-loss interventions vary in their capacity to overcome the body’s appetite feedback circuits by as much as threefold.
A researcher used a validated mathematical model to simulate the body’s weight-loss response to calorie restriction, glucagon-like peptide receptor agonists (GLP-1 RAs, a class of drugs primarily used to treat type 2 diabetes and obesity), and bariatric (gastric bypass) surgery. The model predicted how these interventions influenced body weight by simulating changes in caloric intake, energy use, and appetite over time.
He found that weight loss plateaued at around 12 months with calorie restriction and at around 24 months with GLP-1 RAs or gastric bypass surgery. The drugs and surgery were between 40 and 70 percent more effective at suppressing appetite than calorie restriction, aligning with data indicating that most people find calorie restriction challenging to adhere to, especially for an extended period.
These findings suggest that weight-loss interventions vary in their capacity to overcome the body’s appetite feedback circuits, influencing their effectiveness. Unfortunately, many people regain weight after successful weight loss, possibly due to changes in their gut microbiome. Learn more in this episode featuring Dr. Eran Elinav.
-
Apple cider vinegar promotes weight loss and improves metabolism in young people with overweight or obesity. nutrition.bmj.com
Obesity and overweight are growing global public health concerns, especially among young people. Evidence suggests that apple cider vinegar supports weight loss and improves metabolic health. A recent study found that young people who took apple cider vinegar for 12 weeks lost more weight and exhibited better metabolic parameters than those who took a placebo.
The study involved 120 teens and young adults with overweight or obesity. Participants received 5, 10, or 15 milliliters (5 milliliters = 1 teaspoon) of apple cider vinegar or a placebo diluted in water daily for 12 weeks. They didn’t make any changes to their diets or activity levels. Researchers measured the participants' anthropometrics (weight, body mass index, waist/hip circumferences, and body fat ratio) and blood glucose, triglyceride, and cholesterol levels at the beginning of the study and again at four-week intervals.
They found that participants who took apple cider vinegar lost weight in a dose- and time-dependent manner, with those taking higher doses manifesting the greatest weight loss, which increased as the study progressed. All anthropometric measures improved, too, as did blood glucose, triglyceride, and cholesterol levels. None of the participants taking the vinegar experienced any adverse or ill effects.
These findings suggest that apple cider vinegar promotes weight loss and improves metabolic parameters in young people with overweight or obesity. The investigators noted that these effects occurred without changes to the participants' diets or activity levels, suggesting the effects arose from the vinegar itself. Apple cider vinegar is made by fermenting apple juice. It is rich in vitamins, minerals, amino acids, and polyphenols such as flavonoids, which may confer some of apple cider vinegar’s benefits. Learn about the health benefits of other polyphenols in our overview article.
-
Presence of gut microbe _Alistipes putredinis_ intensifies weight loss during physical activity, new research shows. microbiomejournal.biomedcentral.com
Physical activity is often a fundamental component of weight management strategies. However, some people experience weight loss with physical activity while others do not. A recent study found that differences in the gut microbiome influence the body’s metabolic response to physical activity.
The study involved 307 healthy men and 209 healthy women enrolled in two long-term cohort studies. Researchers analyzed the participants' gut microbial makeup and assessed their physical activity levels over several years.
They found that a specific gut microbe called Alistipes putredinis played a crucial role in how physical activity influenced body weight. Participants with higher levels of A. putredinis experienced more weight loss when they increased their physical activity. Conversely, those with lower A. putredinis levels saw less weight loss in response to physical activity. This pattern was consistent for long-term and short-term physical activity and associated with metabolic processes linked to A. putredinis, such as folate transformation and fatty acid metabolism.
These findings suggest that having a greater abundance of A. putredinis in the gut boosts the positive effects of physical activity on weight management. Interventions aimed at manipulating the gut microbiome could enhance the effectiveness of physical activity in controlling body weight. Learn more about the gut microbiome’s roles in human health in this episode featuring Dr. Eran Elinav.
-
Every 1 percent drop in body weight slows brain aging by nearly nine months, highlighting the substantial, and often overlooked, neuroprotective benef elifesciences.org
Excess body fat harms multiple organ systems, including the central nervous system, potentially accelerating brain aging. A new study shows that a 1 percent weight loss delays brain aging by nearly nine months.
Researchers conducted a study involving 102 participants enrolled in the DIRECT-PLUS study who underwent an 18-month lifestyle intervention to promote weight loss. Using magnetic resonance imaging, the researchers assessed the resting-state functional connectivity in the participants' brains and predicted their brain ages. They also evaluated how various health factors, such as body measurements, blood markers, and fat deposits, affect brain aging.
They found that the brain age prediction model accurately predicted the participants' chronological ages. They also found that brain aging slowed by 8.9 months for every 1 percent of body weight loss, an effect linked with improved liver health and reduced liver, visceral, and subcutaneous fat. Their analysis revealed that lower consumption of processed foods, sweets, and beverages delayed brain aging.
These findings suggest that weight loss may benefit the brain’s aging process, potentially slowing its aging trajectory. They also underscore the importance of maintaining a healthy weight throughout the lifespan to support overall brain health. Sulforaphane, a bioactive compound derived from broccoli, benefits brain health and may influence its aging, too. Learn more in this episode featuring Dr. Rhonda Patrick.
-
Findings suggest restricting eating to an eight-hour window enables similar weight loss as cutting calories by 25 percent. www.latimes.com
Traditional weight-loss programs typically emphasize calorie restriction – often cited as the primary reason participants drop out. But time-restricted eating is a weight loss strategy that limits one’s daily eating window to a specific period without focusing on restricting calories. A new study found that time-restricted eating was as effective as calorie restriction for weight loss.
The study included 90 adults with obesity who followed one of three dietary patterns for a year: time restriction, calorie restriction, and no restriction (a control group). The time-restricted group ate during an eight-hour window, from noon to 8:00 p.m., without limiting calories. The calorie-restricted group cut their calories by 25 percent. The control group ate during a 10-hour (or more) window and did not change their diets. Researchers assessed the participants' body weights, metabolic markers, and caloric intake throughout the study.
They found that the time-restricted and calorie-restricted groups experienced considerable weight loss compared to the control group by the end of the year. The time-restricted group lost more than 10 pounds (~4.8 percent of their body weight), while the calorie-restricted group lost nearly 12 pounds (~5.3 percent). There was no statistically significant difference in weight loss between the two groups. Notably, the control group averaged a 2.4-pound weight gain over the year.
These findings suggest that time-restricted eating is as effective for weight loss as calorie restriction. In this study, the eating window began around noon – often described as a “late” window. However, some evidence indicates that an early eating window is more beneficial than a later one. Learn more about time-restricted eating in this episode featuring Dr. Satchin Panda.
-
Dawn-to-dusk fasting reduces disease risk and improves metabolic health in people with metabolic syndrome. medicalxpress.com
One month of dawn-to-dusk fasting decreases proteins that drive atherosclerosis, heart disease, and cancer in people who have metabolic syndrome, a recent study has found. People who fasted also lost weight and saw improvements in their metabolic and cardiovascular health.
The study involved 14 people who had metabolic syndrome – a constellation of health conditions that increases a person’s risk of heart disease, stroke, and type 2 diabetes. Participants fasted (no food or drink) from dawn to dusk for more than 14 hours every day for four weeks. They ate a pre-fast meal (breakfast) before beginning their fast and a post-fast meal (dinner) after ending their fast each day. Researchers analyzed the proteomes (the collective set of proteins) of the participants' peripheral blood mononuclear cells, a type of immune cell.
They found that proteins that drive atherosclerosis, heart disease, and cancer were decreased, but proteins that suppress cancer and inflammation were increased. Interestingly, they found that levels of apolipoprotein B, a protein associated with the development of atherosclerotic heart disease, were markedly lower after a month of fasting, and these lower levels persisted even one week after the fasting period ended. In addition, the participants lost weight, and their insulin resistance and blood pressure improved.
Evidence suggests that fasting flips a metabolic “switch,” liberating fat stores via fatty acid oxidation and ketone production while safeguarding lean muscle mass and function. Consequently, fasting improves overall body composition but also triggers the activation of biochemical processes and signaling pathways that optimize human performance and physiological function, possibly slowing the processes of aging and disease. Learn more about fasting in our overview article.
-
Estrogen may reduce high-fat diet-induced visceral fat accumulation by decreasing the expression of a vitamin A-converting enzyme - mouse study.(2012) www.sciencedaily.com
From the article:
The hormonal effect seen in these mice relates at least in part to how the female body processes vitamin A, a nutrient that is converted into a variety of compounds. These include a molecule that supports the burning of fat for energy, as well as retinoic acid, the hormone in this study that leads to the formation of visceral fat. The scientists showed that a high-fat diet functions as a switching mechanism that breaks down the fat-burning molecule and leads to activation of the enzyme and production of retinoic acid, ending in the development of visceral fat.
A year ago, Ziouzenkova’s lab identified the one of these enzymes that relates to fat accumulation: Aldehyde Dehydrogenase 1, or Aldh1a1. In the current study, she and colleagues conducted numerous experiments in mice to track the events that followed activation of this enzyme.
The researchers compared normal mice with genetically altered mice lacking the enzyme over almost a year of eating a high-fat diet. Male and female normal mice gained weight on the high-fat diet, as expected, though the females developed more visceral fat that surrounds the organs than did males, a trend also seen in humans as the result of eating excess fat. (In contrast, on a regular diet, men are more likely than women to form abdominal fat.) Both sexes of mice developed peripheral subcutaneous fat, which lies just under the skin and has some benefits.
In mice without the enzyme, however, the males developed some fat but females remained lean, and this occurred even when females ate more food than males. The researchers determined that without Aldh1a1, the females were not producing retinoic acid, and that protected them from producing visceral fat. Meanwhile, males retained the ability to produce retinoic acid.
The scientists then analyzed the proteins contained in fat tissue in male and female mice lacking the enzyme, and saw that only the females' fat cells contained high levels of a protein that releases fat from fat cells to support fat burning. This release led to production of another protein that converts fat to heat, essentially burning the fat, in the form of lipids, away.
“Without production of the hormone retinoic acid, females are burning fat and expending the energy in the form of heat. That’s why they stay very lean,” Ziouzenkova said. “And this process was specifically affecting visceral fat.”
The researchers surgically removed the ovaries of mice to test whether estrogen could be related to visceral fat production in females. As soon as the animals became menopausal and weren’t producing estrogen, they began to produce retinoic acid, which led to visceral fat formation.
“Estrogen was sufficient to protect female mice from both hormonal and, partially, diet-induced obesity. This means estrogen is suppressing activation of the obesity-inducing hormone, and as soon as we lose this estrogen during menopause, the visceral fat starts to grow,” said Ziouzenkova, also an investigator in Ohio State’s Comprehensive Cancer Center.
Using another mouse model that allowed researchers to measure hormone production specifically, the researchers observed that female mice on a regular diet barely produced retinoic acid. However, females on a high-fat diet produced high levels of the hormone and, in turn, showed a nine-fold increase in visceral fat compared to visceral fat developed by males on a high-fat diet. This was the final determinant that the high-fat diet triggers this cascade of events ending in visceral fat formation.
Because the human fat tissue samples the researchers analyzed also showed elevated levels of Aldh1a1 in cells extracted from tissue in obese women, “it could be that what we show about this hormone’s importance to visceral obesity in mice is also true for humans,” Ziouzenkova said.
-
Silencing of estrogen receptor α in a brain area of the hypothalamus led to metabolic syndrome in mice. (2007) www.sciencedaily.com
From the article:
Estrogen receptors are located on cells throughout a woman’s body. Previous studies have shown that one type of estrogen receptor, known as estrogen receptor alpha or ER-alpha, plays a role in regulating food intake and energy expenditure. But scientists have been unable to pinpoint exactly where these fat-regulating receptors reside or how they work to govern these behaviors.
To determine the effect of dwindling estrogen levels in the brain, Clegg and her colleagues are focusing on two ER-alpha rich regions located in the hypothalamus, an area of the brain that controls body temperature, hunger and thirst. The first region, called the ventromedial nucleus or VMN, is a key center for energy regulation.
Using a relatively new gene-silencing technique called RNA interference, the researchers in earlier research deactivated the alpha-receptors in the VMN. The estrogen receptors in other regions of the brain maintained their normal capacity.
When estrogen levels in the VMN dipped, the animals' metabolic rate and energy levels also plummeted. The findings show the animals quickly developed an impaired tolerance to glucose and a sizable weight gain, even when their caloric intake remained the same. What’s more, the excess weight went straight to their middle sections, creating an increase in visceral fat.
The findings suggested that the ER-alpha in this region plays an essential role in controlling energy balance, body fat distribution and normal body weight.
-
Estradiol administered to the amygdala of a menopause rat model prevented weight and abdominal fat gain and improved glucose tolerance. (2017) www.sciencedaily.com
From the article:
“We know as women age and enter into menopause, they tend to gain body weight and body fat, particularly in the abdominal or ‘belly’ area. Excess abdominal fat greatly increases risk for cardio-metabolic diseases,” says Solomon. “While there are likely many factors that are associated with these risks in menopausal women, estrogen loss is associated with body weight and fat gain during menopause. In fact, estrogen treatment can offset this weight gain in many women.”
The medial amygdala (MeA) is a region of the brain that helps regulate body weight and contains an abundance of estrogen receptors (molecules that respond to estrogen). The researchers used an experimental model in rats, which involves removing the ovaries to mimic the hormonal changes of menopause. They targeted estrogen replacement directly in the MeA and found that it prevented weight and abdominal fat gain and improved glucose tolerance, compared to rats in a placebo group. This suggests that the MeA is important in the metabolic health of menopausal females and may be a useful target for treatment.
-
Testosterone therapy may play a small role in temporarily exacerbating or inducing changes in obstructive sleep apnea. (2021) www.sciencedirect.com
From the publication:
The best current evidence suggests that short-term, high-dose testosterone administration mildly worsens OSA [obstructive sleep apnea]. Longer-term TTh [testosterone therapy] in subjects undergoing concomitant weight loss was shown to mildly worsen OSA but only initially. By 18 weeks, patients demonstrated return to baseline levels of OSA risk. These results suggest that TTh’s role in exacerbating OSA is small and may be time limited. However, it is also possible that weight loss acted as a confounding factor. Additional studies are needed to determine if men who are more obese at baseline have a higher risk of developing OSA with TTh than nonobese men. Why testosterone would have a timedependent effect, however, remains unanswered. Regarding the mechanisms by which TTh may worsen OSA, anatomic TTh-induced airway changes and altered sleep stage architecture have been largely refuted. The mechanism of action is more likely related to altered hypoxic and hypercapnic ventilatory response with testosterone administration, though work is still needed to resolve inconsistencies in currently available studies. Until these questions are more fully understood, clinicians may choose to exercise caution in prescribing TTh to individuals with severe, untreated OSA.
-
Improving sleep, diet, fitness, and weight may be alternatives to testosterone therapy. (2018) www.sciencedirect.com
From the publication:
Patient interest in fertility and testicular size preservation and a desire to avoid lifelong medical therapy with testosterone drives the need to identify non-TTh [non-testosterone therapy] for hypogonadism. Medical therapies that can stimulate endogenous testosterone production include hCG [human chorionic gonadotropin], AIs [aromatase inhibitors], and SERMs [selective estrogen receptor modulators], all of which demonstrate efficacy in increasing serum testosterone levels and good safety profiles. Natural therapies to increase testosterone production include diet and exercise, weight loss, improved sleep, decreasing stress, and varicocele repair. Diet, exercise, and weight loss provide a means to potentially reverse comorbidities that are closely linked to hypogonadism. Improvements in sleep quality and duration and decreasing stress are additional lifestyle modifications that can improve testosterone levels without the need for lifelong medication. Varicocele repair also can increase testosterone levels, although rigorous data supporting its use remain lacking. Patients considering TTh should be counseled on disease modification and the possibility of discontinuing TTh in the future, before initiation of therapy, and the alternatives discussed in this review also should be considered first in appropriate candidates.
[…]
Diet, exercise, and weight loss
– 12-wk lifestyle modification program involving aerobic exercise and diet modification significantly increased mean testosterone levels
– 52-wk program of diet and exercise significantly increased mean serum testosterone levels
– Individuals who lost 10% of weight between visits showed a significant increase in testosterone levels
– Weight loss through low-calorie diets or bariatric surgery was associated with significant increases in total testosterone levels
Improvements in sleep
– Men with OSA treated with UPPP had significant 3-mo postoperative increases in testosterone levels
– Restriction of sleep to 5 h/night decreased testosterone levels by 10-15%
Stress reduction
– Men with high stress levels had significantly lower serum testosterone levels compared with controls
– Men with higher work stress had higher than expected incidence of hypogonadism
Varicocele repair
– Varicocelectomy significantly increased mean testosterone levels
– Varicocele repair significantly increased testosterone levels
– Significantly increased total testosterone levels were found at 12-mo follow-up after varicocelectomy
– Mean serum total testosterone significantly increased after varicocelectomy
-
Testosterone levels improved in obese men following a common weight-loss operation. (2015) www.eurekalert.org
From the article:
The aim of the study was to investigate the effect of surgical weight loss following sleeve gastrectomy [removement of about 75 percent of the stomach] on serum testosterone, DHEA (a precursor to testosterone), and prostate-specific antigen (PSA). This clinical study involved 24 obese male patients undergoing gastric sleeve surgery, also called sleeve gastrectomy, at Stanford Hospital. Serum testosterone, DHEA, and PSA were measured before and at three, six, and 12 months after the procedure.
The researchers found that the study group experienced a significant increase in average serum testosterone after undergoing sleeve gastrectomy. At 12 months, testosterone had increased on average from 295 to 423 ng/dL. The normal range for circulating testosterone is 300 to 1000 ng/dL. A person is diagnosed with low serum testosterone when the level drops below 300 ng/dL.
Before the procedure, 63 percent of participants had low testosterone and afterwards, only 41 percent did. The average BMI was 46 before surgery and 31 after the operation. In addition, DHEA also rose, from 12.8 to 39.6 ng/mL, and serum PSA concentration rose over 12 months from 0.62 to 0.75 ng/mL with no change in PSA mass, which is a marker for prostate cancer progression.
[…]
“When you are obese, your fat becomes converted to estrogen, which will compete with testosterone and drive it down,” Dr. Morton said. “The nice thing about what this process does is it creates an autotransfusion of testosterone from yourself. This process occurs because you are losing weight, and therefore losing that estrogen, causing your natural testosterone stores to rise. It’s actually really helpful across the board for these patients.”
-
Testosterone treatment of older men didn`t affect functional status or cognition but increased lean body mass and had mixed metabolic effects. (2008) www.sciencedaily.com
From the article:
Marielle H. Emmelot-Vonk, M.D., of University Medical Center Utrecht, the Netherlands, and colleagues conducted a randomized, placebo-controlled study to assess the effects of testosterone supplementation on functional mobility, cognition, bone mineral density, body composition, lipids, quality of life, and safety parameters in older men with testosterone levels less than 13.7 nmol/L (less than the average level in this age group) during a period of six months. The trial, conducted from January 2004 to April 2005, included 207 men between the ages of 60 and 80 years. Participants were randomly assigned to receive 80 mg of testosterone undecenoate or a matching placebo twice daily for six months.
The researchers found that during the study, lean body mass increased and fat mass decreased in the testosterone group compared with the placebo group but these factors were not accompanied by an increase of functional mobility or muscle strength. Cognitive function and bone mineral density did not change. Insulin sensitivity improved but high-density lipoprotein cholesterol (the “good” cholesterol) decreased. By the end of the study, 47.8 percent in the testosterone group vs. 35.5 percent in the placebo group had the metabolic syndrome (a strong risk factor for cardiovascular disease and type 2 diabetes, a group of several metabolic components in one individual including obesity and dyslipidemia). This difference was not statistically significant.
Quality-of-life measures did not differ aside from hormone-related quality of life in the testosterone group. Adverse events were not significantly different in the two groups. Testosterone supplementation was associated with an increase in the concentrations of blood creatinine, a measure of kidney function, and hemoglobin and hematocrit, two red blood cell measures. No negative effects on prostate safety were detected (some reports have suggested that testosterone therapy could increase the risk of development or progression of prostate disease or cancer).
-
The beneficial effects of 6 months of testosterone treatment on frailty in older men were not maintained 6 months after treatment. (2010) www.sciencedaily.com
From the article:
Frailty is an age-related state of physical limitation caused by the loss of muscle mass and function and can lead to adverse clinical outcomes such as dependency, institutionalization and death. Testosterone levels naturally decline with aging and testosterone replacement is a common therapy. Short-term testosterone treatment in frail elderly men has been shown to improve muscle mass and strength, but until now it has been unclear whether these effects could be maintained post-treatment.
[…]
In this study, researchers evaluated 274 intermediate-frail and frail elderly men aged 65-90 years with low testosterone levels. Study participants received either a testosterone gel or placebo for six months. Assessments were carried out at baseline, the end of treatment and six months after treatment cessation. Researchers found that the increased lean body mass, muscle strength and quality of life after six months of testosterone treatment were not maintained six months after treatment.
“At present, the optimal duration of anabolic hormonal intervention to produce sustained benefits in treating frailty in older men is unknown,” said Wu. “To best interrupt the downward spiral into frailty a greater emphasis should be placed on a multi-disciplinary interventional approach including resistance exercise, diet and other lifestyle options, in conjunction with pharmacological agents.”
-
Long-term testosterone treatment reduced weight by 36 pounds and waist circumference by 3.5 inches in men with low testosterone. (2012) www.sciencedaily.com
From the article:
The investigators restored testosterone to normal levels in 255 testosterone-deficient (“hypogonadal”) men, whose average age was nearly 61 (range, 38 to 83 years). Treatment lasted for up to five years, with injections given at day 1, after 6 weeks and then every 12 weeks after that. Patients did not follow a controlled diet or standard exercise program but received advice to improve their lifestyle habits.
On average, the men weighed 236 pounds before beginning testosterone treatment and 200 pounds after treatment (106.2 versus 90 kilograms), the authors reported. Weight loss was reportedly continuous, with an average reduction in body weight ranging from about 4 percent after one year of treatment to more than 13 percent after five years.
In addition, men lost an average of nearly 3.5 inches (8.8 centimeters) around their waist.
-
Obese teen boys showed up to 50 percent less testosterone than lean boys. (2012) www.sciencedaily.com
From the article:
We were surprised to observe a 50 percent reduction in testosterone in this pediatric study because these obese males were young and were not diabetic,“ says Paresh Dandona, MD, PhD, SUNY Distinguished Professor in the Department of Medicine, chief of the Division of Endocrinology, Diabetes and Metabolism in the UB medical school and first author on the study. "The implications of our findings are, frankly, horrendous because these boys are potentially impotent and infertile,” says Dandona. “The message is a grim one with massive epidemiological implications.”
The small study included 25 obese and 25 lean males and was controlled for age and level of sexual maturity. Concentrations of total and free testosterone and estradiol, an estrogen hormone, were measured in morning fasting blood samples. The results need to be confirmed with a larger number of subjects, Dandona says.
[…]
“The good news is that we know that testosterone levels do return to normal in obese adult males who undergo gastric bypass surgery,” says Dandona. “It’s possible that levels also will return to normal through weight loss as a result of lifestyle change, although this needs to be confirmed by larger studies.”
-
In older men with low testosterone levels, testosterone replacement therapy improved risk factors for cardiovascular disease and diabetes. (2008) www.sciencedaily.comHormones Diabetes Cholesterol Testosterone Triglycerides Metabolic Syndrome Weight Loss Cardiovascular
From the article:
All 95 men in the studies (ages 34 to 69 years) had the metabolic syndrome. To receive this diagnosis, patients must have three of the following five risk factors: increased waist circumference (abdominal fat), low HDL (“good”) cholesterol, high triglycerides (fats in the blood), high blood pressure, and high blood sugar.
The first study showed that testosterone treatment significantly reduced waist circumference, total cholesterol, LDL (“bad”) cholesterol, triglycerides, and body mass index (a measure of body fat). Treatment also increased “good” cholesterol. Improvements were progressive over 12 months, indicating that benefits may continue past a year, Saad said.
In the second study, the researchers divided the patient population into three groups by age: less than 57 years, 57 to 63 years, and more than 63 years. They found that the oldest men had similar improvements in metabolic risk factors to the youngest men.
Additionally, the investigators looked at the degree of testosterone deficiency before treatment. This beginning level of testosterone deficiency did not predict the beneficial outcome, they found. Men whose subnormal testosterone levels were not as low as the others had similar improvements in metabolic risk factors to men with the lowest levels, according to Saad.
-
Testosterone-replacement therapy reduced the prevalence of metabolic syndrome in patients with low testosterone from 56% to 30%. (2012) www.sciencedaily.com
From the article:
“When indicated, testosterone treatment is both essential and safe in elderly patients with symptomatic late onset hypogonadism, or testosterone deficiency,” said study lead author Aksam A. Yassin, M.D., Ph.D., Ed.D., chairman of the Institute of Urology & Andrology in Norderstedt-Hamburg, Germany. “Further analysis is needed to confirm if our findings are due to a direct effect of restoring physiologic testosterone levels.”
Specifically, investigators found that the prevalence of metabolic syndrome dropped from 56 to 30 percent after 57 months of treatment with testosterone-replacement medication to regulate hormone levels. In addition, triglycerides, and levels of blood sugar and pressure significantly decreased, while the average waist circumference shrank by 11 centimeters.
Beginning in 2004, investigators collected data from 261 patients with late-onset hypogonadism, characterized by both low testosterone levels and sexual dysfunction, at three centers in Germany. Patients received 1,000 milligrams of a long-acting testosterone drug, called undecanoate, on the first day of the study, at week six, and then every three months.
-
Weight loss reduced the prevalence of low testosterone levels in overweight, middle-aged men with prediabetes by 46%. (2012) www.sciencedaily.com
From the article:
The study population had 891 middle-aged men, with an average age of 54 years. The men were randomly assigned to receive one of three treatments: 293 men to lifestyle modification, 305 to the diabetes drug metformin and 293 to inactive placebo pills. Lifestyle modifications consisted of exercising for 150 minutes a week and eating less fat and fewer calories.
The results showed that low testosterone levels are common in overweight men with prediabetes, Hayes said. At the beginning of the study, nearly one in four men had low testosterone levels, considered to be below 300 nanograms per deciliter.
With lifestyle modification, the prevalence of low testosterone levels decreased from about 20 percent to 11 percent after one year, a 46 percent decrease, the authors reported. The prevalence of low testosterone was unchanged in the metformin group (24.8 versus 23.8 percent) and the placebo group (25.6 versus 24.6 percent).
Men in the lifestyle modification group lost an average of about 17 pounds (7.8 kilograms) over the one-year study, according to the abstract. The increase in testosterone levels in that group correlated with decreasing body weight and waist size.
“Losing weight not only reduces the risk of prediabetic men progressing to diabetes but also appears to increase their body’s production of testosterone,” Hayes said.
-
Creatine supplementation (10 weeks) increased testosterone levels in collegiate football players. (2006) pubmed.ncbi.nlm.nih.gov
From the publication:
The effects of creatine and creatine plus β-alanine on strength, power, body composition, and endocrine changes were examined during a 10-wk resistance training program in collegiate football players. Thirty-three male subjects were randomly assigned to either a placebo (P), creatine ( C), or creatine plus β-alanine (CA) group. During each testing session subjects were assessed for strength (maximum bench press and squat), power (Wingate anaerobic power test, 20-jump test), and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, IGF-1, and sex hormone binding globulin. Changes in lean body mass and percent body fat were greater (P < 0.05) in CA compared to C or P. Significantly greater strength improvements were seen in CA and C compared to P. Resting testosterone concentrations were elevated in C [creatine group], however, no other significant endocrine changes were noted. Results of this study demonstrate the efficacy of creatine and creatine plus β-alanine on strength performance. Creatine plus β-alanine supplementation appeared to have the greatest effect on lean tissue accruement and body fat composition.
-
Long-term testosterone therapy may help men with deficiency lose weight (-20.3%), maintain their weight loss and reduce death risk. (2019) www.sciencedaily.com
From the article:
“Obesity is very common in men with testosterone deficiency (hypogonadism),” said lead study author Karim Haider, M.D., a urologist and andrologist in private practice in Bremerhaven, Germany.
[…]
The 462 (57.4 percent) patients with obesity were given the choice whether to be treated with long-term testosterone therapy (TTh) with testosterone undecanoate injections (TU) 1,000 mg every 12 weeks. Of these, 273 opted to receive testosterone, and the 189 who declined treatment served as controls.
Over 10 years, the testosterone-treated men lost 20.3 percent of their baseline weight (50.5 lb; 22.9 kg); their waist circumference dropped by 12.5 cm (4.9 in). BMI decreased by 7.3 kg/m2, and the waist-to-height ratio decreased by 0.07.
By contrast, the untreated men gained 3.9 percent of their baseline weight (3.2 kg; 7.1 lb), and their waist size increased by 4.6 cm (1.8 in). In this group, BMI increased by 0.9 kg/m2, and waist-to-height ratio increased by 0.03.
During this time, 12 (4.4 percent) men in the testosterone group died, while in the untreated control group, 57 deaths (30.2 percent), 47 myocardial infarctions (24.9 percent) and 44 strokes (23.3 percent) occurred.
-
Eating late at night promotes weight gain. www.sciencedaily.com
Maintaining a healthy body weight presents challenges for many people. Previous research has shown that the timing of food intake plays important roles in managing body weight. Findings from a recent study suggest that late-night eating is counter to the body’s circadian rhythms, increasing the risk of weight gain.
Circadian rhythms modulate a wide array of the body’s physiological processes, including the production of hormones that regulate sleep, hunger, metabolism, and others, ultimately influencing body weight, performance, and susceptibility to disease. Coordination of meal timing with the circadian rhythm can affect aspects of metabolic health, including glucose regulation and insulin sensitivity.
The study involved 16 adults (average age, 37 years) who had overweight or obesity. The participants followed an “early” eating schedule and then a “late” eating schedule for six days each, separated by a wash-out period of three to 12 weeks. The researchers controlled the participants' caloric intake, physical activity, sleep, and light exposure throughout the two interventions. They also collected adipose tissue samples from the participants for analysis of gene expression. Participants reported their hunger and appetite.
The researchers found that when the participants ate later in the day, their hunger and appetite-regulating hormones increased, but their energy expenditure decreased. In addition, eating late altered biochemical pathways involved in fat metabolism and storage.
These findings suggest that eating late influences appetite, energy expenditure, and molecular pathways in fat tissue, underscoring the role of circadian rhythmicity in bodyweight management. Watch this episode in which Dr. Satchin Panda summarizes tips and strategies that anyone can follow to ensure a healthy circadian pattern.
-
Mouse study suggests that interleukin-6 (IL-6) may regulate body weight by increasing substances in the brain that trigger weight loss. (2012) www.sciencedaily.com
From the article:
The results show that the cells that are affected by interleukin-6 produce substances that not only affect our sense of hunger and fullness but also control the body’s ability to burn fat. “Interleukin-6 increases levels of substances in the brain that trigger weight loss, which could explain why high levels of this molecule lead to weight loss,” says doctoral student Erik Schéle, who is presenting the results in his thesis.
It is known that our normally low levels of interleukin-6 in the brain increase dramatically during an infection, typically accompanied by reduced hunger and fatigue.
“Our previous findings would indicate that interleukin-6 can play a key role in regulating the metabolism of healthy individuals too,” says Erik Schéle.
“This is clearly substantiated by our finding that mice which lack interleukin-6 get fat, and that the metabolism of rats injected with interleukin-6 directly into the brain increases.”
-
12-week exercise program of 40-60 minutes of jogging three days per week significantly improved testosterone and systolic b.p. in overweight men www.sciencedaily.com
40-60 minutes 3x per week:
- Systolic blood pressure: 134 ± 4 vs. 119 ± 3 (after)
- Diastolic blood pressure: 85 ± 2 vs. 75 ± 1 (after)
From the article:
At baseline, the overweight/obese men had significantly lower total, free and bioavailable testosterone level than normal weight men. All of the study volunteers completed a 12-week aerobic exercise plan that entailed 40-60 minutes of walking or jogging on one to three days per week.
[…]
I think decrease in body mass is one of the factors for increasing serum testosterone levels,“ said Hiroshi Kumagai, lead researcher on the study. "However, the degree of weight loss is small, and we found that the increase in vigorous physical activity was independently associated with the increase in serum testosterone levels. So, it seems the increase in physical activity, especially vigorous physical activity, is the main factor for increasing serum testosterone levels.”
-
Seventy percent of adults living in the United States have overweight (BMI greater than 25) or obesity (BMI greater than 30), putting them at increased risk of metabolic disease. Extra fat stored around the body promotes inflammation and insulin resistance, but extra abdominal fat is particularly dangerous. Findings of a recent report suggest consuming foods rich in unsaturated fat and dietary fiber may improve fat distribution in females.
Fat stored in the lower body, called subcutaneous fat, is located just under the skin. Fat stored in the abdominal region, called visceral fat, is wrapped around the internal organs (e.g., the liver, pancreas, and intestines). Visceral fat interferes with lipid metabolism in the liver, promoting insulin resistance, type 2 diabetes, and non-alcoholic fatty liver disease. A diet that includes avocados, which are rich in mono-unsaturated fats and dietary fiber, is associated with lower abdominal obesity.
The investigators recruited 105 adults between the ages of 25 and 45 years who had overweight or obesity. They assigned participants to receive meals with avocado (about one Hass avocado) or meals without avocado that were matched for calories and total fat. The two meals contained different amounts of saturated fat, unsaturated fat, and fiber. Participants consumed their assigned meals once per day for 12 weeks and were told not to change their diet in other ways. Participants completed an oral glucose tolerance test to measure insulin resistance and had their body composition measured using X-ray.
In females, avocado consumption decreased visceral adiposity and the ratio of visceral to subcutaneous fat, indicating an improvement in body fat distribution. Both males and females in the control group experienced a loss of subcutaneous fat and an increase in the ratio of visceral to subcutaneous fat, indicating a worsening of body composition over the 12 weeks. Avocado consumption had no effect on insulin resistance.
The authors concluded that avocado consumption improved body fat distribution in females, but had no effects on body fat distribution in males or on insulin resistance in either males or females.
-
Time-restricted feeding reduces weight gain and cholesterol in male mice. www.sciencedaily.com
A Western diet pattern, characterized by a low intake of fruits and vegetables and a high intake of sugar and processed foods, promotes the development of obesity and metabolic disease. Time restricted eating has been shown to decrease weight and improve metabolic health in humans. However, factors such as age and sex modulate both susceptibilty to obesity and likelihood of responding to weight-loss treatments. Authors of a new report found that male mice experienced greater metabolic benefit from time-restricted feeding than females.
Time-restricted eating, the practice of limiting food intake to an 8- or 12-hour window, is an emerging therapy for the treatment and prevention of metabolic diseases. Much of the research about time-restricted eating in humans is based on research of time-restricted feeding in mice, which has elucidated many of the cellular mechanisms related to [time-restricted eating’s benefits.](https://journals.physiology.org/doi/full/10.1152/ajpregu.00775.2005) These two terms distinguish which population, humans or non-human animals, is practicing time-restricted food intake.
The prevalence of obesity is on the rise in the industrialized world, a problem compounded by an increasing average age in the same populations. The accumulation of extra fat throughout life puts a person at greater risk of metabolic disease as they age. Females are more likely to gain and retain fat mass than males; however, pre-menopausal females tend to have lower rates of type 2 diabetes and cardiovascular disease due to the protective effects of estrogen. Previous research in humans has demonstrated weight loss and improved metabolic health with time-restricted eating; however, additional research is needed to understand the sex- and age-dependent effects of time-restricted eating.
The researchers used male and female mice of two ages: three months old (equivalent to 20-year-old humans) and 12 months old (equivalent to 42 year-old-humans). They fed mice a chow diet representative of a Western diet pattern with 17 percent of calories from sugar (human equivalent of about 25 ounces of soda per day) and 45 percent of calories from fat including lard and soybean oil. Current dietary guidelines recommend limiting solid fats such as lard). Half of the mice had 24-hour access to food while the other half only had restricted access, limited to just nine hours per day. Mice continued their diet for a total of 12 to 13 weeks. After 10 weeks, the researchers measured changes in the animals' body weight, glucose sensitivity, serum cholesterol, fatty liver, muscle performance, and immune response when challenged with bacterial endotoxin.
Although mice in the time-restricted feeding group consumed the same amount of food as mice with constant access to food, time-restricted feeding resulted in 15 percent less weight gain in young male mice and 23 percent less weight gain in older male mice. Time-restricted feeding did not significantly prevent weight gain in female mice. Male mice also experienced a greater reduction in serum cholesterol with time-restricted feeding compared to females. Both older male and female mice had lower rates of insulin resistance and fatty liver while on time-restricted feeding. This protection was likely due to changes in gene expression that increased glucose uptake by and decreased glucose output from the liver. In young male mice, time-restricted feeding preserved muscle mass, function, and performance, but not in young females. Finally, when challenged with bacterial endotoxin, older mice practicing time-restricted feeding were significantly more likely to survive septic shock than mice with 24-hour access to food, demonstrating better health and resilience.
Time-restricted feeding improved survival of septic shock and provided protection against insulin resistance and fatty liver in both sexes; however, male mice experienced greater reductions in body weight and serum cholesterol and maintained greater muscle mass and performance compared to female mice. The authors noted that their research is of particular interest considering the increased risk of severe COVID-19 illness in those with poor metabolic health.
- [Link to full publication.](https://pubmed.ncbi.nlm.nih.gov/34407415/)
- Learn more about the effects of time-restricted feeding and its effects on obesity, muscle mass, and heart health from expert Dr. Satchin Panda in this episode of the Found My Fitness podcast.
- Visit our topic article on time-restricted feeding to learn even more.
-
Increases in brain-derived neurotrophic factor from aerobic exercise associated with appetite suppression, weight loss, and improved blood pressure www.sciencedaily.com
From the article:
The team evaluated blood levels of BDNF before and after a three-month program of aerobic exercise in 15 overweight or obese men and women. The seven men and eight women, ages 26 to 51, worked out on a treadmill and bicycle. They were asked about their calorie intake and told to continue eating their usual number of calories. The participants were unaware that one of the study’s objectives was to evaluate changes in food intake.
At the end of the study, the subjects had decreased BMI, waist circumference, and blood pressure, the data showed. They also reported consuming fewer calories than at the beginning of the study. Over the three months, BDNF levels greatly increased. This higher the concentration of BDNF, the less the subject’s intake of calories and the greater the weight loss, Araya said.
Thus, it is possible that increases in BDNF suppress appetite, she said. They did not test appetite suppression directly, but some past studies have shown that aerobic exercise suppresses appetite.
-
Increased visceral fat impairs cognition through chronic microglial activation mediated by IL-1 beta release [animal research] www.sciencedaily.com
Scientists find that visceral fat, a type of adipose tissue that produces high levels of inflammatory signals known as adipokines, impair learning and memory in mice by setting off an inflammatory cascade mediated by the release of IL-1 beta, which crosses the blood-brain barrier leading to chronic activation of microglia.
From the article:
“We have identified a specific signal that is generated in visceral fat, released into the blood that gets through the blood brain barrier and into the brain where it activates microglia and impairs cognition.”
Visceral fat as the ring leader:
They looked further and found that just transplanting the visceral fat caused essentially the same impact as obesity resulting from a high-fat diet, including significantly increasing brain levels of interleukin-1 beta and activating microglia. Mice missing interleukin-1 beta’s receptor on the microglia also were protected from these brain ravages.
[…]
To measure cognitive ability, the scientists looked at mice’s ability to navigate a water maze after 12 weeks on a high- or low-fat diet. They found it took the normal, or wild type, mice consuming the higher fat diet as well as the visceral transplant recipients with NLRP3 intact longer to negotiate the water maze. In fact, while they could reach a platform they could see, they had trouble finding one beneath the water’s surface that they had been taught to find. Mice with the interleukin-1 receptor knocked out, could find it just fine, Stranahan says.
The high-fat diet, transplant mice also had weaker connections, or synapses, between neurons involved in learning and memory. Mice on a high-fat diet but missing NLRP3 were spared these changes, like mice on a low-fat diet.
-
As a cofactor in the biosynthesis of carnitine, vitamin C may have a role in enhancing PPAR-alpha-dependent fatty acid oxidation www.nature.com
From the publication:
Ascorbic acid is a known cofactor in the biosynthesis of carnitine, a molecule that has an obligatory role in fatty acid oxidation […] Ascorbic acid supplementation increased the mRNA levels of PPARα and its target enzymes involved in fatty acid β-oxidation in visceral adipose tissues. Consistent with the effects of ascorbic acid on visceral obesity, ascorbic acid not only inhibited hepatic steatosis but also increased the mRNA levels of PPARα-dependent fatty acid β-oxidation genes in livers. Similarly, hepatic inflammation, fibrosis, and apoptosis were also decreased during ascorbic acid-induced inhibition of visceral obesity. In addition, serum levels of alanine aminotransferase, aspartate aminotransferase, total cholesterol, and LDL cholesterol were lower in HFD-AA-fed mice than in those of HFD-fed mice.
A few bullet points:
- Reduced visceral obesity
- Reduced hepatic inflammation
- Increased expression of PPAR-a
- Improved markers of liver health and cholesterol
-
Vitamin C deficiency impairs fatty acid oxidation ("fat burning") during exercise. nutritionandmetabolism.biomedcentral.com
Vitamin C is essential for the synthesis of carnitine, a compound required for fatty acid oxidation – the utilization of fatty acids as energy – commonly referred to as “fat burning.” Carnitine deficiency is associated with fatigue and poor exercise tolerance. Findings from a new study suggest that high dose vitamin C improves fatty acid oxidation.
The two-part clinical study involved 22 men and women between the ages of 18 and 38 years. Fifteen of the participants had marginal vitamin C blood levels (less than 34 micromoles per liter) and seven had adequate vitamin C blood levels (greater than 34 micromoles per liter).
In the first part of the study, all of the participants completed a 60-minute treadmill walk at 50 percent of their VO2 max. Fat utilization during the treadmill walk was 25 percent lower among participants with marginal vitamin C status, suggesting that vitamin C status affects fuel utilization during exercise.
In the second part of the study, the participants' vitamin C levels were depleted over a period of four weeks. Then they took either 500 milligrams of vitamin C or a placebo every day for four additional weeks. At the end of the eight-week period, the average blood vitamin C levels in the supplemented group were 41.7 micromoles per liter, but average levels among the depleted group were 9.7 micromoles per liter. Fatty acid utilization in the supplemented group was approximately four times greater than the vitamin C depleted group. Poor fatty acid oxidation during exercise was related to higher levels of fatigue.
These findings suggest that low vitamin C status is associated with poor fatty acid oxidation during exercise and may explain why some people are unsuccessful when trying to lose weight.
-
Large doses of vitamin C might mitigate the body's stress response, thereby improving immunity. www.sciencedaily.com
The human body responds to mental stress by releasing hormones called corticosteroids, triggering the body’s fight or flight response. Chronic activation of these hormones can impair immune function, increasing susceptibility to infection and disease. Findings from an early study in mice demonstrate that vitamin C mitigates the body’s stress response, thereby improving immunity.
The authors of the study immobilized mice for an hour every day for three weeks to induce stress. They also fed the mice 200 milligrams of vitamin C daily – roughly equivalent to several grams per day in humans. A control group of mice also received vitamin C but they were not subjected to stress.
The stressed mice that received large doses of vitamin C in their diets exhibited fewer signs of stress as evidenced by lower levels of corticosteroid hormones as well as other physical manifestations, such as weight loss. The mice also exhibited higher levels of IgG, the most abundant antibody in circulation, responsible for binding a broad selection of pathogens, including viruses, bacteria, and fungi, to prevent infection. Interestingly, the non-stressed mice that received large doses of vitamin C exhibited even greater increases in IgG, suggesting that stress cancels out some of the beneficial effects of the vitamin.
These findings suggest that high dose vitamin C might improve immune function, especially during times of mental and physical stress.
-
Consuming diet drinks along with carbohydrates may have negative effects on the brain and metabolic health. www.inverse.com
Low-calorie sweeteners – also known as non-nutritive sweeteners, artificial sweeteners, or sugar substitutes – contain few, if any, calories but deliver a greater intensity of sweetness than sweeteners with calories. They are ubiquitous in the Western diet, appearing in beverages, baked goods, frozen desserts, chewing gum, and many other foods. A new study demonstrates that consuming low-calorie sweeteners in tandem with carbohydrate-rich foods alters brain function and impairs metabolism.
The health effects of consuming low-calorie sweeteners are not well understood. Whereas some evidence suggests that substituting sugar-sweetened beverages with low-calorie sweeteners can aid in weight loss, other studies suggest that low-calorie sweeteners may contribute to weight gain and diabetes risk, especially in men.
This study involved 45 healthy adults who did not regularly consume low-calorie sweeteners. Over a period of 10 days, each of the participants drank seven 12-ounce beverages that contained sucralose (a low-calorie sweetener), sugar, or a combination of sucralose and maltodextrin (a polysaccharide produced from grain starch). Before and after the study period, participants underwent oral glucose tolerance tests, sensory tests, and neuroimaging to assess insulin sensitivity, taste perception, and brain response to taste, respectively.
The authors of the study found that drinking the beverage sweetened with the sucralose-maltodextrin combination reduced the participants' insulin sensitivity and altered their brain responses to sweet tastes. These findings suggest that consuming low-calorie sweeteners while eating or drinking high carbohydrate foods or beverages may have negative effects on metabolism.
-
When healthy, lean individuals ate a Western-style diet for one week, their hippocampal-dependent learning and memory and appetite control declined. royalsocietypublishing.org
The Western Style Diet, sometimes referred to as Standard American Diet (SAD), is a dietary pattern characterized by high intake of refined carbohydrates, fatty meats, added fats, and sodium, and low intake of whole grains, fruits, and vegetables. The Western dietary pattern has been implicated in the pathogenesis of many chronic diseases and conditions, including overweight and obesity, type 2 diabetes, high blood pressure, and heart disease. Findings from a recent study suggest that the Western dietary pattern impairs hippocampus-dependent learning and memory and drives loss of appetite control.
The hippocampus is a small organ located within the brain’s medial temporal lobe. It is associated primarily with memory (in particular, the consolidation of short-term memories to long-term memories), learning, and spatial navigation. Data from rodent studies suggest that adherence to a Western dietary pattern impairs hippocampal-dependent learning and memory (HDLM). The hippocampus also plays a role in food intake by regulating appetite. Altered hippocampal function subsequent to exposure to a Western-style diet may create a vicious cycle state that promotes increased consumption of unhealthy foods that, in turn, drives further hippocampal dysfunction.
The study involved 110 lean, healthy Australian adults between the ages of 17 and 35 years who adhered to a healthy, non-restrictive dietary pattern. The authors of the study randomized the participants to either a one-week Western-style diet intervention group or a habitual-diet control group.
On the first and eighth days of the study, the participants in the Western diet group ate a breakfast that included a toasted sandwich and a milkshake (high in saturated fat and added sugar). On the second through seventh days of the study, the participants ate two Belgian waffles for either breakfast or dessert for four of the study days. On the other two study days, they obtained their main meal and a drink or dessert from a set of options from a popular fast-food chain. They followed their normal dietary pattern for all other meals. The participants in the control group ate a breakfast consisting of a toasted sandwich and a milkshake (low in saturated fat and added sugar) on the first and eighth days and followed their normal diet for all other meals.
The authors of the study assessed the participants' HDLM function as well as their appetite control before and after the intervention and control periods and again at a three-week follow-up assessment. They found that among those who followed the Western-style diet, HDLM performance declined, compared to the control group. Their appetite control declined as well, and this was strongly correlated with HDLM decline.
These findings suggest that even short-term consumption of a Western-style diet may impair learning and appetite control due to impaired hippocampal function. This lack of appetite control could promote overeating and drive weight gain.
-
Weight loss and health improvements with Mediterranean, intermittent fasting, and Paleo diets www.sciencedaily.com
Roughly two-thirds of all adults living in the United States are overweight or obese. Losing weight presents many challenges, however, and popular weight-loss diets and dietary patterns are not always successful or sustainable. A recent study found that people who followed an intermittent fasting, Mediterranean, or Paleo diet lost weight and showed improvements in health, but adherence to the diets varied.
Intermittent fasting is a broad term that describes periods of fasting between meals that can last several hours to days. Intermittent fasting increases the production of ketones due to the use of stored fat as an energy source. It also activates some of the same genetic pathways as caloric restriction. The authors of this study defined intermittent fasting as 25 percent of the participants' usual dietary intake two days per week.
The Mediterranean diet is a dietary pattern thought to confer health benefits found traditionally in Mediterranean countries. It is characterized by high consumption of vegetables, olive oil, and dairy products and moderate consumption of protein. The Paleo diet is based mainly on foods presumed to be available to Paleolithic humans. It includes vegetables, fruits, nuts, roots, meat, and organ meats and excludes dairy products, grains, refined sugar, legumes, and other processed foods. The authors of this study modified the typical Paleo plan to include limited consumption of dairy, legumes, and grains.
The study mimicked “real world” dieting strategies in that each participant could choose which of the three dietary patterns they would follow for 12 months. In addition, they received no nutritional counseling other than a single, 30-minute session in which they learned about their self-selected diet. The authors of the study collected information about the participants' dietary intake, body weight and composition, blood pressure, physical activity, and various blood biomarkers, including glycated hemoglobin, a measure of long-term blood glucose control (also known as HbA1c).
Approximately 54 percent of the participants chose to follow the intermittent fasting diet, 27 percent chose the Mediterranean diet, and 18 percent chose the Paleo diet. At the end of the 12-month study period, adherence to the three diet plans was 54 percent for intermittent fasting, 57 percent for the Mediterranean, and 35 percent for Paleo.
Study participants lost weight with all three plans, but those who practiced intermittent fasting lost more (4 kg) than those who followed the Mediterranean (2.8 kg) or Paleo diets (1.8 kg). Those who followed the intermittent fasting and Mediterranean diet plans showed reductions in blood pressure (4.9 mm Hg and 5.9 mm Hg, respectively). Those who followed the Mediterranean diet experienced a 0.8 mmol/mol reduction in HbA1c.
These findings suggest that people can lose weight and improve health while following different dietary patterns as long as those patterns include healthful foods and are personally sustainable.
-
Abdominal obesity is associated with fatal heart attacks and strokes independent of other risk factors. www.escardio.org
Myocardial infarction (MI), commonly referred to as heart attack, occurs when one of the heart’s coronary arteries is blocked suddenly or has poor blood flow. One of the principal risk factors for MI in men and women is abdominal obesity. The relative risk of recurrent cardiovascular disease-related death after having MI is approximately 30 percent higher than the risk among people without MI. Findings from a recent study suggest that abdominal obesity increases the risk of a fatal recurrent MI or stroke.
According to the World Health Organization, the waist circumference range for increased cardiovascular risk is 94 to 102 centimeters for men and 80 to 88 centimeters for women. Values above this range place people at greatly increased risk. Waist circumference measurement is particularly relevant in people whose body mass index is normal or overweight.
The study was based on data gathered from more than 22,000 people living in Sweden who were between the ages of 35 and 77 years old and had experienced their first MI. The participants were followed for approximately four years for recurrent cardiovascular events, including nonfatal MI, coronary heart disease death, or stroke.
The findings indicated that during the follow-up period, 7.3 percent of the men and 7.9 percent of the women had a recurrent cardiovascular event. The majority of the study participants had a waist circumference that was higher than the WHO’s recommended thresholds. Having a larger waist circumference was associated with roughly 20 percent greater risk of recurrent cardiovascular-related event, regardless of age, body mass index, or other risk factors, especially in men. Interestingly, participants who were overweight were less likely to experience a recurrent cardiovascular disease-related event compared to those who were normal weight or obese.
These findings demonstrate that waist circumference may be a useful tool in the clinical setting for identifying patients at increased risk for recurrent MI and suggest that strategies to reduce abdominal fat (such as lifestyle modification) may reduce the risk of fatal heart attacks and strokes.
-
Eating a low-fat diet may reduce testosterone levels in men. www.eurekalert.org
As many as half of all men living in the United States have low testosterone levels, a condition characterized by libido loss and erectile dysfunction. Lifestyle modifications such as exercise and diet (to promote weight loss) are often recommended as a means to restore testosterone levels. Findings from a new study suggest that eating a lower-fat diet may contribute to low testosterone levels.
The study drew on data from 3,100 men between the ages of 18 and 80 years who were enrolled in NHANES studies between 1998 and 2012. The participants completed 2-day diet records and provided blood samples for testosterone analysis. The men’s diets were classified as low fat, low carbohydrate, Mediterranean, or non-restrictive.
Men who ate a low fat or Mediterranean diet had lower testosterone levels on average than men who ate a non-restrictive diet. These findings suggest that low-fat dietary recommendations for men who have low testosterone may have unintended consequences that should be weighed against any possible benefits associated with weight loss.
-
More abdominal fat drives loss of fluid intelligence whereas more muscle mass protects against loss. www.sciencedaily.com
Fluid intelligence – the ability to creatively solve problems without prior knowledge or learning – declines with age, often as early as the third decade of life. Evidence from a new study suggests that body composition influences declines in fluid intelligence, and these declines may be related to immune system activation.
Body composition describes an individual’s body fat and lean mass. Excess body fat promotes systemic inflammation (which can promote neuroinflammation) and drives immune-related inflammatory processes. Lean muscle mass, however, may be protective against inflammation.
The study involved more than 4,400 middle-aged and older men and women living in the United Kingdom. The participants' body composition, cognitive function, blood leukocytes (white blood cells), and variables such as age, education level, and socioeconomic status were measured every other year for a period of six years.
The authors of the study found that higher levels of body fat, especially abdominal fat, were associated with greater losses of fluid intelligence. The losses appeared to be related to sex-specific increases in blood leukocyte counts and inflammation, as evidenced by higher levels of C-reactive protein.
These findings point to the importance of maintaining a healthy body weight throughout life as a strategy to reduce or prevent cognitive decline.
-
Sustained weight loss in women over 50 reduces breast cancer risk www.eurekalert.org
Breast cancer is one of the leading causes of death among women living in the United States, claiming the lives of approximately 41,000 women each year. Being overweight or obese increases a woman’s risk of developing breast cancer. Findings from a new study indicate that women who lose weight after the age of 50 years and keep the weight off have reduced risk of developing breast cancer.
More than two-thirds of women living in the United States are overweight or obese. Excess body fat increases a person’s risk for developing type 2 diabetes, a known risk factor for cancer. Body fat also alters hormone levels, which may increase the risk of developing hormone-sensitive cancers, such as breast cancer. In addition, body fat secretes a wide array of pro-inflammatory substances that damage DNA and inhibit apoptosis.
The study involved more than 180,000 women who were 50 years of age and older from cohorts of 10 different prospective studies. The women were weighed three times over a period of 10 years. Those who lost weight and kept it off had a lower risk of breast cancer than women who did not lose weight.
Among women who lost 4 to 10 pounds, 10 to 20 pounds, or 20 or more pounds, risk decreased by 13 percent, 16 percent, and 26 percent, respectively. Among women who lost 20 or more pounds but gained a portion of the weight back, risk was reduced by 23 percent.
These findings point to the importance of public health interventions that promote weight loss among women as a means to reduce cancer risk.
-
Mice fed a high-fat, low-carbohydrate diet were better able to combat the flu virus and had better survival rates than mice fed a normal diet. www.sciencedaily.com
More than 20,000 people die every year in the United States from influenza-related complications. Findings from a new study demonstrate that a ketogenic diet confers protection against the influenza virus and improves survival rates in mice.
A ketogenic diet is a high fat, moderate protein, low carbohydrate eating pattern that causes the body to oxidize fat to produce ketones for energy. The ketogenic diet has been used in the clinical setting to reduce seizures in children and is being investigated for the treatment of traumatic brain injury, Alzheimer’s disease, weight loss, and cancer.
The authors of the study fed a ketogenic diet or regular chow to mice for seven days and then infected them with influenza virus. The mice that ate the ketogenic diet lost less weight, maintained better blood oxygen levels, and had improved survival rates compared to the mice that ate the regular chow. In addition, the mice on the ketogenic diet had higher levels of specialized T-cells in their lungs that enhanced airway cell mucus production to improve lung barrier function.
Interestingly, the beneficial effects of a high fat diet were only observed with the ketogenic diet. Feeding the mice a high-fat, high-carbohydrate diet or providing exogenous ketones in the diet had no beneficial effects against influenza virus.
-
Time-restricted eating may be linked to greater motivation to engage in voluntary exercise. www.sciencedaily.com
Limiting food intake and engaging in exercise are highly effective strategies for weight loss. People who are obese are often sedentary, however, due to physical limitations and a lack of motivation to exercise. Compelling findings from a new study in mice suggest that ghrelin, a hormone linked to appetite, may increase motivation to engage in exercise.
Ghrelin, which is produced primarily in the stomach, stimulates appetite, increases food intake, and promotes fat storage in mice and humans. It is often referred to as the “hunger hormone” and is linked to reward-driven behavior. Previous studies have shown that ghrelin administration increases activity in mice in anticipation of food.
The current study involved mice that were fed on a time-restricted eating schedule (twice daily) versus mice that were allowed to eat freely throughout the day. Both groups of mice ate roughly the same amount of food each day. The mice that were fed on the time-restricted schedule were more motivated to engage in voluntary exercise and ran on an exercise wheel for longer periods. The increase in the animals' activity corresponded to increases in ghrelin levels. Conversely, inhibiting ghrelin attenuated the animals' motivation to exercise.
Hunger-related behaviors such as increased activity are essential to animals in the wild or human hunter-gatherers because they must forage and seek out or hunt for food. Tapping into these ancient hormonally-driven behaviors may help resolve modern-day concerns of obesity and lack of exercise. However, a small study in humans demonstrated that time-restricted eating decreased morning levels of ghrelin (and subsequently appetite), so more studies on the effects of time-restricted eating and ghrelin in humans are needed.
-
A small randomized controlled clinical trial finds time-restricted eating within a 6-hour window (fasting for 18 hours) without reducing calories or losing weight improves insulin sensitivity, beta cell function, blood pressure, oxidative stress and reduces evening appetite.
All eating was supervised and approached metabolic ward rigor. The improvements in metabolism were independent of weight loss and the reduction in blood pressure was so significant that it was comparable to the standard of care blood pressure medication (ACE inhibitors).
The time-restricted eating they started early with the first meal at 8 am and dinner before 3 pm. The importance of time of day for this type of intermittent fasting is still an interesting open question, especially since there’s a lot of advocacy for late eating among 16:8 advocates, however, insulin sensitivity usually declines later in the day (and is exacerbated by the production of melatonin, which has an effect of shutting off insulin secretion). Interestingly, Dr. Satchin Panda has been gathering data via his mobile app (my circadian clock) that suggests an eating window later in the day may be comparable to an early eating window.
To learn more about time-restricted eating and intermittent fasting check out the two separate podcasts I did with Dr. Satchin Panda. The episodes have summaries, timelines, and transcripts!
Round 2 episode: https://www.foundmyfitness.com/episodes/satchin-round-2
Round 1 episode: https://www.foundmyfitness.com/episodes/satchin-panda
-
A new study shows the "obesity paradox,” the idea that obese people live longer than those of normal weight, may be explained by muscle mass. journals.plos.org
A new study shows the “obesity paradox,” the idea that obese people live longer than those of normal weight, may be explained by muscle mass.
After accounting for muscle mass, high BMI no longer associates with greater survival. Some have hypothesized that excess fat stores are beneficial for counteracting episodes of catabolic stress. However, the risk of death increased with low muscle mass and greater body fat.
This study also found that skeletal muscle mass was an independent risk factor for mortality in the general population, and this was more pronounced among younger adults…which is interesting because most studies on muscle mass and mortality focus on a geriatric population.
Skeletal muscle mass could directly influence survival and could protect against loss of functional status due to aging or the onset of chronic disease. However, since this is an observational nature study, a causal relationship cannot be determined. There is always the possibility that there may be other confounding health-related factors that were not accounted for.