Not all calories are the same when it comes to maintaining weight after a diet. Calories from fats, proteins and carbohydrates affect the metabolism in the same way, nutritionists say.
Researchers at Boston Children's Hospital are testing the theory by observing 21 adults who follow a strict weight loss program. Volunteers consume pre-prepared meals containing 60% of their usual calorie intake.
As a result, participants lost 10 to 15% of their weight in 12 weeks .
Researchers are testing three types of diets to analyze their effects on metabolism and which one is most effective in maintaining the results achieved by the regime.
After losing weight, the metabolism slows down and therefore it is difficult to maintain the weight, experts explain.
All participants follow the three diet regimens. Each of them lasts four weeks.
What do the results show? Consumption of energy decreases the most when following a low- fat diet , and the least - with a low- carbohydrate diet, similar to the Atkins diet, experts explain.
A low glycemic index diet slows down the metabolism, in a slightly higher percentage of a protein-rich diet. Scientists have found that this diet also shows few signs of increased stress hormones.
If we want to lose weight and not regain the previous pounds, we must be careful with the amount of food consumed, to avoid products with high glycemic index, refined sugars, processed foods. They can slow down our metabolism and lead to weight gain , experts say.
Critics point to a shortcoming of the current study, as many restrictive, low-calorie diets are included. According to them, more research is needed to prove the results, especially in real conditions.
The study was published in the Journal of the American Medical Association .