A low carbohydrate diet could help people maintain weight loss by increasing the number of calories burned, according to US research published in The BMJ. The researchers say this effect may improve the success of obesity treatment, especially for people with high insulin secretion. Energy expenditure declines with weight loss as the body adapts by slowing metabolism and burning fewer calories, often leading to lost weight being regained. But little is known about how dietary composition influences this adaptive response in the long term. One hypothesis, the carbohydrate–insulin model, proposes that recent increases in the consumption of processed, high glycaemic load foods trigger hormonal changes that increase hunger, leading to weight gain. Researchers at the Boston Children’s Hospital compared the effects of diets with different carbohydrate-to-fat ratios on energy expenditure. The trial involved 234 overweight adults aged 18–65 years with a body mass index of 25 or higher who initially took part in a weight loss diet for about 10 weeks. After shedding 12% on the run-in diet, participants were randomly assigned to one of three test diets for 20 weeks: high (60%), moderate (40%) or low (20%) carbohydrate diets. Each participant was provided with fully prepared meals of similar protein and fat content. After adjusting for potentially influential factors, they found that total energy expenditure over the 20 weeks was significantly greater for participants on the low carbohydrate diet than for those on the high carbohydrate diet: 209–278 kilocalories more per day, or an increase of 50–70 kilocalories a day for each 10% reduction in the contribution of carbohydrates to total energy intake. For people with the highest insulin secretion at the start of the study, the difference in total energy expenditure between low and high carbohydrate diets was even greater: up to 478 kilocalories a day, consistent with the carbohydrate–insulin model. If this effect persisted, “it would translate into an estimated 10 kg weight loss after 3 years, assuming no change in calorie intake,” the authors noted.
*the above article is from The Medical Journal of Australia.
Full journal article: the British Medical Journal.
