ARS | Publication request: Effects of dietary composition of energy expenditure during weight-loss maintenance

Submitted to: Journal of the American Medical Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 8, 2012
Publication Date: June 27, 2012
Citation: Ebbeling, C.B., Swain, J.F., Feldman, H.A., Wong, W.W., Hachey, D.L., Garcia-Lago, E., Ludwig, D.S. 2012. Effects of dietary composition of energy expenditure during weight-loss maintenance. Journal of the American Medical Association. 307(24):2627-2634.

Interpretive Summary: Most people have difficulty keeping weight off because weight loss through diets has been shown to reduce the calories the body burns during activities or resting. We conducted a study designed to find out if the amount of calories the body burned was related to the diet nutrient content. In the study, 21 participants lost 10 to 15% of their body weight during a three-month dietary weight-loss program. One month later, these participants were placed on one of three diets for a month: a low-fat diet; a low-carbohydrate diet similar to an Atkins diet; and a low-glycemic-index diet similar to a Mediterranean diet. The participants were then switched to the other two diets. The low-glycemic-index diet increased the amount of calories the body burned and lowered the risk for heart disease and diabetes. The low-carbohydrate diet led to the most calories burned but also led to increases in stress and risks for heart disease and diabetes. The low-fat diet led to the least amount of calories burned and increased the risk of heart disease. Therefore, the low-glycemic-index diet appeared to be the most appropriate diet for people who desire to lose weight and keep the weight off without increasing their risks for stress, heart disease, or diabetes.

Technical Abstract: Reduced energy expenditure following weight loss is thought to contribute to weight gain. However, the effect of dietary composition on energy expenditure during weight-loss maintenance has not been studied. To examine the effects of 3 diets differing widely in macronutrient composition and glycemic load on energy expenditure following weight loss, a controlled 3-way crossover design involving 21 overweight and obese young adults was conducted at Children's Hospital Boston and Brigham and Women's Hospital, Boston, Massachusetts, between June 16, 2006, and June 21, 2010, with recruitment by newspaper advertisements and postings. After achieving 10 to 15% weight loss while consuming a run-in diet, participants consumed an isocaloric low-fat diet (60% of energy from carbohydrate, 20% from fat, 20% from protein; high glycemic load), low-glycemic index diet (40% from carbohydrate, 40% from fat, and 20% from protein; moderate glycemic load), and very low-carbohydrate diet (10% from carbohydrate, 60% from fat, and 30% from protein; low glycemic load) in random order, each for 4 weeks. Primary outcome was resting energy expenditure (REE), with secondary outcomes of total energy expenditure (TEE), hormone levels, and metabolic syndrome components. Compared with the pre-weight-loss baseline, the decrease in REE was greatest with the low-fat diet (mean [95% CI], -205 [-265 to -144] kcal/d), intermediate with the low-glycemic index diet (-166 [-227 to -106] kcal/d), and least with the very low-carbohydrate diet (-138 [-198 to -77] kcal/d; overall P = .03; P for trend by glycemic load = .009). The decrease in TEE showed a similar pattern (mean [95% CI], -423 [-606 to -239] kcal/d; -297 [-479 to -115] kcal/d; and -97 [-281 to 86] kcal/d, respectively; overall P = .003; P for trend by glycemic load < .001). Hormone levels and metabolic syndrome components also varied during weight maintenance by diet (leptin, P < .001; 24-hour urinary cortisol, P = .005; indexes of peripheral [P = .02] and hepatic [P = .03] insulin sensitivity; high-density lipoprotein [HDL] cholesterol, P < .001; non-HDL cholesterol, P < .001; triglycerides, P < .001; plasminogen activator inhibitor 1, P for trend = .04; and C-reactive protein, P for trend = .05), but no consistent favorable pattern emerged. Among overweight and obese young adults compared with pre-weight-loss energy expenditure, isocaloric feeding following 10 to 15% weight loss resulted in decreases in REE and TEE that were greatest with the low-fat diet, intermediate with the low-glycemic index diet, and least with the very low-carbohydrate diet.