In a recent study, published in British Medical Journal, it is revealed that low-carb diet help people burn more calories and keep their weight off. Most people who lose weight from dieting regains it within one or two years, as the body adapts by burning fewer calories and slowing metabolism. The study led by Boston Children’s Hospital in conjunction with Framingham State University, finds that eating food with low carbohydrate content promotes burning of more number of calories.
Researchers conducted a study called the “Framingham State Food Study”, on which, diet of the participants was strictly controlled by providing them with fully prepared food-service meals for 20 weeks. In addition, they monitored the participants’ weight and measured metabolic hormones, insulin secretion, and total energy expenditure (number of calories burned). Co-principle investigator David Ludwig, MD, Ph.D said that it is the longest and largest feeding study to experiment the ‘Carbohydrate-Insulin Model’ which offers a new way to think about obesity and its treatment.
According to the model, the processed carbohydrates that constituted the most in a diet during low-fat era have raised the level of insulin, influencing fat cells to store more amount of calories. As the number of calories present in the rest of the body decreased, metabolism slowed down while increasing hunger which led to weight gain.
Following careful screening of 1,685 potential participants, 234 overweight adults were initially provided with a weight-loss diet for about 10 weeks. Of these, 164 participants who lost about 10-14% of their body weight were moved to the study’s maintenance phase. These participants were then assigned to follow low-, moderate, and high-carbohydrate diets for another 20 weeks, on which carbs comprised of 20, 40, and 60% of total calories respectively.
All the three groups were provided with high-quality carbs, using whole instead of processed grains and minimizing sugar. Additionally, the total calorie intake of all the groups were balanced to maintain weight loss. Main objective of this phase was to compare energy expenditure, which was calculated by a gold-standard method, utilizing doubly labelled water. Over the 20-week period, it was observed that total energy expenditure was notably higher in low-carbohydrate diet as compared to high-carbohydrate diet. Further, participants following low-carb diet burned nearly 250 kilocalories more than those on the high-carb diet on daily basis.
If this difference persists with no weight loss during 20 weeks of the study, in three years, the effect would promote weight loss about 20 pounds with no change in calorie intake, according to the researchers. Calorie expenditure difference in low-carb diet – versus high-carb diet were observed to be even greater in people with highest secretion of insulin at baseline, shedding about 400 kilocalories in a day.
While the study findings challenge the long-known belief that all calories are same to the body, it did measure satiety and hunger. However, other studies have suggested that low-carbohydrate diets reduces hunger, leading to weight loss in long term.