Study under review: Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial.
In long-term trials (longer than 12 months) researchers conducting many studies have consistently seen weight loss on all kinds of diets—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 of their initially lost weight. A version of the carbohydrate-insulin model of obesity (CIMO) 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. 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.
Other Articles in Issue #50 (December 2018)
Interview: Kevin Klatt, Ph.D. & Katherine Pett, MS, RDN, LDN
We chat with Kevin and Katherine about their experience podcasting and cover some possible pitfalls of n-of-one nutritional experiments.
Can omega-3 supplementation during pregnancy affect growth and development in children?
This secondary analysis of a large and long trial found some promising results.
Ashwagandha: can it improve strength and body composition in resistance-trained men?
This study aimed to find out if the herb ashwagandha pairs well with resistance training in men.
Mini: Which types of supplements lead the pack for serious adverse events in the U.S.?
Many supplements have some side effects, but there are a small handful that can cause more trouble than others. We summarize the findings of recent research taking a look at the worst offenders.
Too much of a good thing: folic acid and vitamin B12 supplementation and cancer risk in the elderly
When researchers looked at how B12 and folic acid affect osteoporosis in the elderly, they didn't find a strong positive effect. They did, however, notice an uptick in cancer rate. This study took a deeper look at the matter.
Spirulina: A weight loss aid?
Spirulina and exercise are both thought to help shed some pounds. How do they work in combination?
Does caffeine actually help you lose weight?
Maybe, but the effects are modest and the results are confounded due to combining it with other supplements. Read on for the details from this recent meta-analysis