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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.