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For weight maintenance, is low-carb king?

According to the carbohydrate-insulin model of obesity, refined carbs make more insulin which leads to more fat down the road. This study aimed to test this model.

Study under review: Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial.

Introduction

In long-term trials (longer than 12 months) researchers conducting many studies[1] have consistently seen weight loss[2] on all kinds of diets[3]—from extremely low-carb to extremely low-fat. But maintaining weight loss is a struggle, with nearly all participants in these trials regaining some or all[4] of their initially lost weight. A version of the carbohydrate-insulin model of obesity (CIMO)[5] posits that this inability to keep weight off may be due to the pro-insulinogenic effects of refined and high glycemic carbohydrate in the diet.

This version of the CIMO hypothesis goes as follows: carbohydrate in the diet (particularly high glycemic and refined) elevates insulin secretion, which suppresses the release of stored body fat and drives fat that may be circulating in the bloodstream into storage. A decrease of circulating fat decreases the energy available for the body to use. This drop in energy availability can lead to a decline in energy expenditure and increase food intake[6]. Thus, it is hypothesized that the development of obesity or weight regain is a consequence of carbohydrate-induced insulin production driving fat into storage, preventing it from being used for energy. This is in contrast to the energy balance model, which states that equally swapping carbohydrate for fat in the diet will not notably affect body fat levels nor energy expenditure.

Dr. David Ludwig, a supporter of the CIMO hypothesis, has just published a long-term, randomized trial designed to answer the question: Will varying the carbohydrate-to-fat ratio in the diet have an effect on energy expenditure during weight loss maintenance? If the CIMO hypothesis holds true, then a low-carb diet should increase energy expenditure relative to a low-fat diet.

Researchers conducting long-term diet studies have seen many participants fail to maintain their weight loss. The carbohydrate-insulin model of obesity hypothesizes that refined and high-glycemic carbs are a major contributor to this issue. The randomized trial under review examines the effects of various carbohydrate-to-fat ratios in the diet on energy expenditure during a period of weight maintenance.

Who and what was studied?

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