Preventing decreased energy expenditure following weight loss is an important component of long-term body weight stabilization. According to the carbohydrate-insulin model of obesity, the high ratio of blood insulin-to-glucagon concentration following consumption of a high-glycemic load meal directs metabolic fuels toward fat storage. As a result, energy expenditure may decrease in response to a low-glycemic load diet, which may favor weight regain. Using doubly labeled water methodology, the longest feeding study addressing this question found that total energy expenditure was higher on a low- versus high-carbohydrate diet throughout 20 weeks of weight-loss maintenance. However, the validity of the doubly labeled water methodology for diets varying in macronutrient composition has been called into question.

The aim of the current study, conducted by Cara Ebbeling and David Ludwig (New Balance Foundation Obesity Prevention Center, Boston Children’s Hospital) and colleagues, was to assess the estimated energy requirement to maintain a mean 10.5% weight loss on diets containing 60%, 40%, and 20% of total energy as carbohydrate, controlled for 20% protein. Having previously reported higher total energy expenditure on a low- versus high-carbohydrate diet, the researchers expected to observe a similar difference in energy requirement. Consistent results would lend support to using doubled labeled water methodology to measure total energy expenditure when comparing different macronutrient diets.

Study results, published in The Journal of Nutrition, found that energy requirement was higher on a low- versus high-carbohydrate diet during weight-loss maintenance in adults. These data are consistent with the carbohydrate-insulin model and also support the validity of the doubly labeled water method with diets varying in macronutrient composition. The magnitude of this effect – an increase of about 50 kilocalories/d for every 10% decrease in carbohydrate as a proportion of total energy – was commensurate with previously reported changes in total energy expenditure. These findings suggest that one may be able to eat more on a low-carbohydrate diet without gaining more weight. Although further research is warranted, this study provides important insights into the metabolic effects of dietary composition.

Reference Ebbeling CB, Bielak L, Lakin PR, Klein GL, Wong JMW, Luoto PK, Wong WW, Ludwig DS. Energy Requirement Is Higher During Weight-Loss Maintenance in Adults Consuming a Low- Compared with High-Carbohydrate Diet. The Journal of Nutrition, Volume 150, Issue 8, August 2020, Pages 2009–2015,

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