Carbohydrates
Episodes
In this clip, DrS. Ben Bikman and Rhonda Patrick reveal how nutrition enhances glycemic control, reduces glucose spikes, and supports long-term...
In this clip, Dr. Rhonda Patrick explores the effects of sleep deprivation on insulin signaling, diabetes risk, appetite regulation, and metabolic health.
In this clip, Drs. Peter Attia and Rhonda Patrick discuss VO2 max testing, peak fat oxidation, and the longevity benefits of elite cardiovascular fitness.
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In this clip, DrS. Ben Bikman and Rhonda Patrick reveal how nutrition enhances glycemic control, reduces glucose spikes, and supports long-term...
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In this clip, Dr. Rhonda Patrick explores the effects of sleep deprivation on insulin signaling, diabetes risk, appetite regulation, and metabolic health.
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In this clip, Drs. Peter Attia and Rhonda Patrick discuss VO2 max testing, peak fat oxidation, and the longevity benefits of elite cardiovascular fitness.
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A ketogenic diet is high in fat, moderate in protein, and low in carbohydrates. Research shows that it mimics fasting by inducing metabolic switching – the c...
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In this clip, Ronald Krauss discusses the negative combinative effect of consuming added sugars and saturated fat together.
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The classic ketogenic diet is high in fat and low in protein and carbohydrates. The ease of following a ketogenic diet varies from person to person, dependin...
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Poor sleep reduces the body's insulin sensitivity and changes a person's appetite, increasing the preference for high carbohydrate foods like pizza, pasta, a...
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Q&A Mashup #3: Fasting PremiumThis episode of the aliquot features a collection of clips covering a range of topics related to fasting - both intermittent and prolonged. Specific topics ...
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In this clip, Dr. Peter Attia explains the complex relationship that exists between cancer cells, the immune system, and IGF-1.
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Dr. Eric Verdin explains the importance of the insulin signaling pathway in aging and highlights both animal and human research in this area.
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Dr. Matthew Walker describes how sleep deprivation drives a preferential desire for high carbohydrate foods.
Topic Pages
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Sugar-sweetened beverages (SSBs)
Sugar-sweetened beverages are liquid carriers of mono- and disaccharide carbohydrates that are rapidly absorbed, causing acute glycemic and insulinemic spikes.
News & Publications
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For decades, nutrition debates have often centered on whether people should cut carbohydrates or cut fat. A new study examined how low-carbohydrate and low-fat diets were associated with heart disease risk when the quality and sources of the foods people ate were taken into account.
The researchers analyzed data from 198,473 men and women in three long-running health studies in the United States. Participants were free of diabetes, cardiovascular disease, and cancer at the start, and completed detailed diet questionnaires about every four years over periods spanning more than 30 years. Rather than simply comparing low-carbohydrate and low-fat diets, the researchers separated these eating patterns into healthier and less healthy versions based on the foods people ate. They then tracked new cases of coronary heart disease and, in smaller groups of participants, examined blood markers related to cholesterol, triglycerides, inflammation, and metabolism.
- Higher-quality lower-carbohydrate diets were linked to a 15% lower rate of coronary heart disease. The defining features of these diets were fewer refined grains, added sugars, and potatoes, along with a greater reliance on plant-derived sources of fat and protein.
- Higher-quality lower-fat diets were linked to a 13% lower rate of coronary heart disease. These diets emphasized whole grains, fruits, legumes, and other higher-quality carbohydrate foods, along with more plant protein and less animal fat.
- Lower-quality lower-carbohydrate diets were linked to a 14% higher rate of coronary heart disease. These diets contained more animal fat and animal protein and fewer whole grains, fruits, legumes, and nonstarchy vegetables.
- Lower-quality lower-fat diets were linked to a 12% higher rate of coronary heart disease. These diets emphasized refined carbohydrates and animal protein while containing less vegetable fat.
The biomarker findings pointed to common patterns despite the different carbohydrate and fat targets. People whose eating habits most closely matched the healthier versions of these diets tended to have lower triglycerides, higher HDL cholesterol, and lower levels of an inflammation marker. LDL cholesterol and non-HDL cholesterol did not clearly differ across the dietary patterns. One possible explanation for these findings is that the healthier low-carbohydrate and low-fat diets shared many of the same food characteristics despite their different labels. Both tended to emphasize higher-quality carbohydrate sources while containing lower amounts of refined carbohydrates, saturated fat, trans fat, and processed meat. That overlap may help explain why the two healthier approaches showed similarly lower rates of coronary heart disease.
The findings are observational, so they cannot show that the eating patterns caused the differences in heart disease risk. Still, the study suggests that rather than focusing on a single macronutrient or dietary extremes, it is more useful to build a diet around minimally processed foods rich in vitamins, minerals, fiber, and other beneficial compounds. In this clip, I break down what I eat in a day.
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Not everyone handles carbohydrate intake the same way. In fact, the spike in blood sugar that follows a meal—called the postprandial glycemic response—can vary widely between individuals, even when they eat the same food. A recent study found that individual responses to carbohydrate-rich meals, such as rice or potatoes, depended strongly on a person's underlying metabolic health, with people who were more insulin resistant showing much greater blood sugar spikes.
Researchers measured blood glucose levels continuously in 55 participants (using continuous glucose monitors) as they ate seven standardized carbohydrate meals, including bread, rice, potatoes, and grapes. They also tested whether "preloading" a carbohydrate-rich meal with fat, protein, or fiber could blunt blood sugar spikes. Participants underwent intensive metabolic testing and provided blood and stool samples so the researchers could analyze insulin resistance, beta cell function, blood lipids, proteins, and gut microbes.
The study revealed striking differences between individuals in their responses to different carbohydrate meals. Rice triggered the highest average blood sugar spike, but the size of that spike varied by person. For example, people who responded most strongly to potatoes were 25% more likely to be insulin resistant and have weaker beta cell function, while those who spiked after grapes were more insulin sensitive. Those who spiked in response to rice were more likely to be Asian; those who spiked in response to bread tended to have higher blood pressure. Preloading with fat, fiber, or protein worked better for people with good insulin sensitivity.
Molecular analyses revealed that insulin-resistant participants had higher levels of triglycerides linked to poor metabolic health, while those with elevated blood pressure showed distinct patterns in circulating metabolites. The gut microbiome also differed between high and low responders, with microbial pathways involved in carbohydrate metabolism more active in those with larger blood sugar spikes.
These findings suggest that a one-size-fits-all approach to managing blood sugar may fall short. Understanding a person's unique metabolic profile—as well as their microbiome—may be essential for preventing or managing conditions like type 2 diabetes and cardiovascular disease. Learn more about the gut microbiome's role in regulating blood glucose and cholesterol in this clip featuring Dr. Michael Snyder, the lead investigator on this study.
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Animal-based low-carbohydrate diets increase the risk of high uric acid levels by 41%, especially in people with overweight, while plant-based low-carb diets show no similar risk. nutritionj.biomedcentral.com
Uric acid, a natural waste product found in the blood, can accumulate and cause gout and other serious health issues when levels become too high. Although low-carbohydrate diets are often popular for weight loss and metabolic health, their usual focus on protein and fat—especially from animal sources—may lead to hyperuricemia, a condition characterized by increased uric acid levels. A recent study found that people who followed low-carbohydrate diets high in animal products were 41% more likely to have hyperuricemia than those on plant-based low-carbohydrate diets.
Researchers evaluated the overall, animal-based, and plant-based low-carbohydrate eating patterns of nearly 40,000 adults. Then, they examined how these patterns related to hyperuricemia, defined as uric acid levels above 7.0 milligrams per deciliter for men and 6.0 for women.
Participants with higher overall low-carbohydrate diet scores were 41% more likely to have hyperuricemia than those with lower scores. This risk was primarily associated with diets high in animal-based protein and fat, which were linked to a 28% greater risk, while plant-based low-carbohydrate diets showed no increased risk. Among participants with overweight, the association was even stronger: Those with the highest scores for animal-based low-carbohydrate diets were 39% more likely to have hyperuricemia.
These findings suggest that animal-based low-carbohydrate diets raise the risk of high uric acid levels, particularly in people with overweight. Low-carbohydrate diets centered on plant foods, however, may offer a way to lower carbohydrate intake without increasing the risk of hyperuricemia. Learn how to follow a plant- and fiber-rich, low-carbohydrate (ketogenic) diet in this clip featuring Dr. Dominic D'Agostino.
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Individualized responses to macronutrients influence metabolic health, with consequences for people with type 2 diabetes. www.sciencedaily.com
Carbohydrates are the principal driver of insulin secretion, facilitating the uptake and metabolism of this macronutrient. However, a recent study found that fats and proteins also stimulate insulin secretion, potentially affecting people with type 2 diabetes.
Researchers collected pancreatic islet cells responsible for insulin secretion from 140 donors after their deaths. About half of the donors had type 2 diabetes. They exposed the cells to carbohydrates, fats, and proteins and assessed insulin secretion.
They found that most donors' islet cells exhibited a robust insulin response to carbohydrates, a moderate response to protein, and a low response to fat. However, some donors' cells elicited responses to protein (9%) and fat (8%) greater than their response to carbohydrates. Cells from donors with type 2 diabetes exhibited diminished responses to carbohydrates and fats, but their protein response was preserved.
These findings suggest that insulin responses to macronutrients differ among individuals, with some preferentially responding to proteins and fats over carbohydrates. They also suggest that higher protein diets could benefit people with type 2 diabetes. Some evidence suggests that current guidelines for protein intake are too low, with implications for people more responsive to protein. Learn more about protein requirements in this clip featuring Dr. Stuart Philips.
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Prostate cancer is a leading cause of cancer death among men in the United States. While some prostate cancers respond well to local treatment, many cases require systemic treatments, such as chemotherapy or hormone therapies, which can have many side effects. Because having overweight or obesity increases the risk of death from prostate cancer](https://acsjournals.onlinelibrary.wiley.com/doi/full/10.1002/cncr.22443), newer and alternative therapies that slow cancer growth and help patients lose weight are needed. Findings of a new report show that a low carb diet generates ketones and other metabolic compounds associated with slower prostate cancer growth.
Low carbohydrate and ketogenic diets are popular with adults looking to lose weight, but they also have therapeutic power for a growing list of diseases such as epilepsy, [diabetes](https://www.magonlinelibrary.com/doi/full/10.12968/pnur.2020.31.4.176), Parkinson’s disease, and some cancers. In addition to the metabolic benefits of weight loss, many anticancer compounds are produced during ketosis such as beta-hydroxybutyrate, a short-chain fatty acid with documented antioxidant and anti-inflammatory effects. Additional research is needed to characterize the wide range of molecules generated on a low carb diet and explore their relationship to prostate cancer growth.
The investigators recruited participants who had recurrent prostate cancer and a BMI in the overweight or obese range (greater than 24). They assigned participants to consume a low carbohydrate diet (less than 20 grams of carbohydrates per day) for six months or continue their habitual diet. Participants provided a blood sample to measure metabolic and cancer biomarkers at multiple time points.
The investigators found increased concentrations of multiple ketone bodies in the blood and increased expression of genes for ketone production, indicating participants succeeded in maintaining ketosis. A low carbohydrate diet altered serum concentrations of multiple amino acids, such as glycine, alanine, and asymmetric dimethylarginine, and increased the expression of genes involved in the synthesis of malate, citrate, and branched-chain amino acids. The researchers found a relationship between increased concentrations of ketosis-related compounds and prostate specific antigen (PSA) double time (a marker of prostate cancer growth rate), indicating that cancer growth was reduced as ketosis intensified.
These results show that metabolites produced in response to a ketogenic diet may contribute to the beneficial effects of a low carb diet for patients with prostate cancer.
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Spices dampen pro-inflammatory response to a high-saturated fat, high-carbohydrate meal. www.sciencedaily.com
Eating a meal that is high in saturated fat and refined carbohydrates increases blood glucose and blood lipid levels. In turn, the body launches an inflammatory response. Chronic inflammation is associated with an increased risk of developing cardiovascular disease. Findings from a new study suggest that adding a spice mixture to a high fat/high sugar meal can dampen the body’s inflammatory response, potentially reducing the associated risk of cardiovascular disease.
Spices are derived from the seeds, roots, bark, or flowers of plants. Research indicates that spices contain bioactive compounds that exert antioxidant, antimicrobial, and anti-inflammatory effects.
The crossover, randomized, controlled trial involved 12 middle-aged men who were overweight or obese and had at least one risk factor for cardiovascular disease. Each of the men consumed three versions of a high-saturated fat, refined carbohydrate meal, providing approximately 1,000 calories per meal, separated by a three-day washout period. One meal contained no additional spices, one contained a 2-gram spice blend (representing low spice intake), and one contained a 6-gram spice blend (representing high spice intake, roughly one teaspoon to one tablespoon). The spice blend contained a mixture of spices and herbs commonly consumed in the American diet, including basil, bay leaf, black pepper, cinnamon, coriander, cumin, ginger, oregano, parsley, red pepper, rosemary, thyme, and turmeric. The participants provided blood samples before and multiple times after consuming the meals.
The blood samples revealed that consumption of the meal containing the 6-gram spice blend reduced levels of pro-inflammatory proteins IL-1 beta, IL-8, and TNF-alpha. At six hours after consuming the 6-gram spice meal, levels of IL-1 beta were more than 1,300 percent lower than after consuming the meal without spices or with 2 grams of spices. IL-1 beta is a proinflammatory cytokine produced by macrophages and is an important mediator of the body’s inflammatory response.
These findings suggest that consumption of spices can mediate the proinflammatory effects of a high-saturated fat, refined carbohydrate meal. Nutritional interventions that emphasize the consumption of spices might reduce inflammation and decrease the risk of cardiovascular disease associated with unhealthy diets.
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Brain aging emerges in the late 40's but dietary ketosis increases overall brain activity and stabilizes functional networks. news.stonybrook.edu
Insulin resistance and poor blood glucose control – defining characteristics of type 2 diabetes – drive changes associated with brain aging and cognitive decline. A growing body of evidence suggests that dementia is the manifestation of insulin resistance and altered metabolism in the brain. A recent study suggests that dietary patterns that promote ketosis improve brain metabolism and function.
Ketosis is a metabolic state that results in the body’s production and use of ketones (byproducts of fatty acid metabolism). It occurs under conditions of fasting, starvation, and low carbohydrate intake. Ketones induce physiological and metabolic responses to promote brain health.
The study had multiple components. First, the authors of the study investigated the time course of human brain aging. Using functional MRI (fMRI) data from more than 900 people between the ages of 18 and 88 years, they determined that neural network stability is a biomarker of brain aging, and the loss of network stability manifests as early as the fifth decade of life (average age, 47 years). They found that the greatest changes in the brain occur around the age of 60 years.
Then they performed fMRI scans on 12 young adults (average age, 28 years) to assess how different energy sources – glucose versus ketones – alter brain function. Each participant underwent three scans under different dietary conditions: a normal diet without fasting, a normal diet with overnight fasting, or a ketogenic diet for one week. They performed fMRI scans on 30 young adults (average age 29 years) 30 minutes after they took an oral bolus of either glucose or ketones or after following their normal diet with overnight fasting. The authors of the study measured the participants' blood glucose and ketone levels before and after each of the scans.
The fMRI scans revealed that ketones increased overall brain activity and stabilized functional networks, but glucose had the opposite effect, regardless of whether the ketones were produced endogenously or supplied from exogenous sources. These findings suggest that dietary interventions that increase ketone production may be useful in mitigating the harmful effects of glucose on the brain.
Certain dietary patterns promote ketosis. For example, the Ketoflex 12/3 diet, a form of time-restrictive eating that limits the period during which a person eats to a 12-hour window at least three hours before bedtime, promotes the production of ketones. Watch this clip in which Dr. Dale Bredesen describes this novel dietary protocol and how it improves cognitive function.
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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.
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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.
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Alterations in gut microbial fermentation modulate the efficacy of exercise for diabetes prevention and management. www.cell.com
Public health officials and healthcare providers commonly recommend exercise as a strategy to prevent or manage the symptoms of type 2 diabetes, but the cardiometabolic response to exercise is variable. Whereas exercise improves insulin sensitivity and promotes cardiovascular health in most adults (responders), exercise exerts a paradoxical effect in which metabolic health is compromised in as many as 69 percent of adults (non-responders). Findings from a recent study suggest the variable effects of exercise in people with prediabetes may be due to alterations in gut microbial fermentation.
Microbial fermentation is the process by which gut bacteria break down and utilize carbohydrates in the gut. The metabolites produced during microbial fermentation include short-chain fatty acids and branched-chain amino acids, which are absorbed and used by the host. Short-chain fatty acids improve symptoms of diabetes, but branched-chain amino acids have the converse effect
The study involved both humans and mice. The human study included 39 overweight or obese men with prediabetes who were between the ages of 20 and 60 years. Participants were randomized to engage in either sedentary activities or supervised exercise training for 12 weeks. They maintained their usual diet throughout the study period. At the end of the 12-week period, fecal microbial samples from two of the participants (responders and non-responders) were transplanted into obese mice.
The results demonstrated that the responders' microbiota displayed increased production of short-chain fatty acids, whereas those of the non-responders displayed increased production of brain-chain amino acids. Fecal microbial transplantation from responders mimicked the effects of exercise on alleviation of insulin resistance in the mice, but fecal transplants from the non-responders did not. These findings may augment and facilitate clinical management of symptoms of diabetes.
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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.
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High glycemic index diets may trigger insomnia www.sciencedaily.com
Roughly one in four women living in the United States suffers from insomnia. Lack of sleep is associated with an increased risk for car accidents and poor mental and physical health. A new study suggests that intake of high glycemic index foods may increase the risk of developing insomnia among postmenopausal women.
Glycemic index is a value (between 0 and 100) assigned to a defined amount of a carbohydrate-containing food based on how much the food increases a person’s blood glucose level within two hours of eating, compared to eating an equivalent amount of pure glucose. Glucose has a glycemic index value of 100. Examples of high glycemic index foods include white bread, rice, potatoes, sweets, and many packaged breakfast cereals.
The cross-sectional study was based on data collected from the Women’s Health Initiative Observational Study and included more than 50,000 postmenopausal women living in the United States who were between the ages of 50 and 79 years. In addition to providing information about their dietary intake, each of the women rated the quality of their sleep and the frequency with which they experienced certain sleep problems, including insomnia.
The results indicated that women who ate high glycemic index diets were more likely to develop insomnia. These findings suggest that dietary modification to reduce the intake of high glycemic foods may reduce the risk of developing insomnia in postmenopausal women.
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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.
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Study demonstrates that exercising before eating breakfast burns more fat, improves insulin sensitivity, & increases glucose uptake into muscle. www.sciencedaily.com
Exercise promotes the uptake of glucose into muscle cells and increases insulin sensitivity. Other physical adaptations occur during exercise, as well, including increased muscle mass, decreased fat mass, and improved mitochondrial function. Previous research has demonstrated that training in the fasted state promotes greater glucose tolerance and insulin sensitivity and induces higher fatty acid oxidation compared to training in the fed state. A recent study bolsters these findings, demonstrating that exercising before eating breakfast may enhance some of the beneficial effects of exercise.
The six-week, single-blind, randomized, controlled trial involved 30 overweight or obese men who engaged in moderate-intensity cycling either before or after eating a high-carbohydrate, mixed-macronutrient breakfast. The men exercised for three, 30-minute sessions the first week and progressed to three, 50-minute sessions over the remaining weeks.
The men who exercised before eating had nearly 2-fold higher whole-body lipid utilization rates as well as decreased carbohydrate utilization compared to the men who exercised after eating. The effects were sustained throughout the entire six-week study period. These findings suggest that exercising before eating breakfast burns more fat, improves insulin sensitivity, and increases glucose uptake into muscle tissue compared to exercising after eating breakfast. Exercising after eating may blunt these effects, however.
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Insulin Sensitivity and Glucose Tolerance Are Altered by Maintenance on a Ketogenic Diet (2010) academic.oup.com
Low-carbohydrate, ketogenic diets (KD) are frequently implemented in efforts to reduce or maintain body weight, although the metabolic effects of long-term exposure to this type of diet remain controversial. This study assessed the responsivity to peripheral and central insulin, glucose tolerance, and meal-induced effects of consuming a KD in the rat. After 8 wk of consuming chow or KD, caloric intake after peripheral or central insulin and insulin and glucose levels after a glucose challenge were assessed. In a separate group of rats, glucose and insulin responses to either a low- or high-carbohydrate test meal were measured. Finally, rats maintained on KD were switched back to a chow diet, and insulin sensitivity and glucose tolerance were evaluated to determine whether the effects of KD were reversible. Maintenance on KD resulted in decreased sensitivity to peripheral insulin and impaired glucose tolerance. Furthermore, consumption of a high-carbohydrate meal in rats that habitually consumed KD induced significantly greater insulin and glucose levels for an extended period of time, as compared with chow-fed controls. Responsivity to central insulin was heightened in KD rats and associated with increased expression levels of insulin receptor mRNA. Finally, returning to a chow diet rapidly reversed the effects of KD on insulin sensitivity and glucose tolerance. These data suggest that maintenance on KD negatively affects glucose homeostasis, an effect that is rapidly reversed upon cessation of the diet.
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People who consumed 3-4 servings of fruits, vegetables, legumes, and a higher fat consumption (35% of energy) was associated with lower mortality. www.sciencedaily.com
A diet consisting more than 60% of energy from carbohydrates (including refined) was related to higher mortality, although not with the risk of cardiovascular disease. The research on dietary fats found that they are not associated with major cardiovascular disease, but higher fat consumption was associated with lower mortality; this was seen for all major types of fats (saturated fats, polyunsaturated fats, and monounsaturated fats), with saturated fats being associated with lower stroke risk. The data are from the Prospective Urban Rural Epidemiology (PURE) study which followed more than 135,000 people from 18 low-income, middle-income, and high-income countries. The study asked people about their diet and followed them for an average of seven and half years. The data was adjusted for age, sex, energy intake, current smoking status, urban or rural location, physical activity, baseline diabetes, education, and other dietary variables (white meat, red meat, bread, and cereal intake). However, this is a prospective study which means causation cannot be established.
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Genetically lowering plasma insulin levels by 25% extended median lifespan by 11% in female mice fed a low-calorie/high-carb/low-fat diet and by 3% in female mice fed a high-calorie/high-fat/low-carb diet.
This study looked at the effects of genetically lowering insulin levels in older mice. Unfortunately, the male mice did not have lower plasma levels of insulin despite genetically lowering insulin-genes and so the effect on lifespan could not be determined in male mice.
The female mice were fed two diets: (diet A: moderate-energy diet of 4.68 kcal/g, with 20% of calories from protein, 25% from fat, and 55% from carbohydrate; diet B: high-energy diet of 5.56 kcal/g, with 16% of calories from protein, 58% from fat, and 26% from carbohydrate).
Interestingly, the lowering of circulating insulin through gene manipulation had a more profound effect on median lifespan in female mice fed the low-calorie/high-carb/low-fat diet (11% extension) versus the high-calorie/low-carb/high-fat diet (3% extension). It is important to note that diets A and B were not matched for the type of fat content, protein levels, or micronutrient composition, so there are numerous potential factors that could have impacted diet-dependent outcomes.
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Disruption of the gut microbiome and gut barrier may be the primary cause of age-related inflammation which accelerates the aging process. www.sciencedaily.com
This study showed that older mice have imbalances in the bacterial composition in the gut which then leads to the breakdown of the gut barrier and the release of bacterial products that trigger inflammation and impair immune function.
We know that inflammation has recently been identified as the key driver of aging in 4 different age groups including elderly, centenarians, semi-supercentenarians, and supercentenarians. We also know that lack of fermentable fiber starves the gut microbiome and causes the bacteria to eat the gut barrier which is made of carbohydrates and this results in the breakdown of the barrier and inflammation.
For more information on why fermentable fiber is so important for the gut microbiome and what good sources are…listen to my podcast with gut experts, Drs. Justin and Erica Sonnenburg. YouTube: https://youtu.be/gOZcbNw7sng
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People with the highest fiber intake had ~80% greater chance of living long & healthy life out of all other dietary factors looked at. www.sciencedaily.com
other factors including total carbohydrate intake, glycemic index, glycemic load, and sugar intake. Successful aging was defined as including an absence of disability, depressive symptoms, cognitive impairment, respiratory symptoms, and chronic diseases including cancer, coronary artery disease, and stroke.
The gut is a major source of inflammation and also the major regulator of the immune system. Fermentable fiber feeds the beneficial bacteria in the gut which then prevents them from being forced to cannibalize the gut barrier (which causes inflammation) and it allows them to produce signaling molecules (short chain fatty acids) which make the immune system better. Also, many foods that contain fiber such as vegetables and fruits also have many important micronutrients and other plant compounds that play a role in successful aging. For more on the importance of fiber in successful aging watch my interview with the authors of The Good Gut, Drs. Justin and Erica Sonnenburg: https://youtu.be/gOZcbNw7sng