A new study published in the journal Science Translational Medicine, conducted by a team of physiologists at the University of Bath, in the United Kingdom, questions the popular belief that the subsistence allowance intermittent fasting, such as alternate day fasting or ‘5: 2’, are the most effective for losing weight as it is lost less than with traditional diets.
In recent years, diets in which you fast a few days a week have gained in popularity, reinforced by images of miraculous transformations of people’s weight and backed by celebrity endorsements.
But to date, data on the effectiveness of fasting compared to more traditional diets, which aim to reduce calorie intake over the course of a full week, has been limited. Now, the new study reinforces this evidence and indicates that fasting is “nothing special.”
Participants in his randomized control trial lost less weight when fasting compared to those on a traditional diet, even when their calorie intake was the same overall.
In the trial, organized by a team from the University’s Center for Nutrition, Exercise and Metabolism (CNEM), participants were assigned to one of three groups:
Group 1, who fasted every other day, with a fast day followed by a day in which they ate 50% more than usual. Group 2, who reduced calories in all daily meals by 25%. Group 3, who fasted every other day (in the same way as Group 1) but followed their fast day with a day in which they ate 100% more than usual.
Participants in all three groups consumed a typical diet of about 2,000-2,500 kcal a day on average at the start of the study. Over the course of the three-week follow-up period, the two energy-restricted groups reduced this intake to an average of 1500-2000 kcal. While Groups 1 and 2 reduced their calorie intake by the same amount in different ways, Group 3’s diet made them fast without reducing total calories.
The results revealed that the group that did not follow the diet (group 2) lost 1.9 kg in just three weeks, and DEXA body scans revealed that this weight loss was almost entirely due to a reduction of body fat content.
In contrast, the first fasting group (Group 1), which experienced the same reduction in calorie intake by fasting on alternate days and eating 50% more on non-fasting days, lost almost the same amount of body weight (1.6 kg), but only half of this weight loss was due to reduced body fat and the rest to muscle mass.
Group 3, who fasted but increased their energy intake by 100% on non-fasting days, did not need to tap into their body’s fat stores for energy, and therefore weight loss was negligible.
Professor James Betts, director of the Center for Nutrition, Exercise and Metabolism at the University of Bath, who led the research, explains: “Many people believe that fasting-based diets are especially effective for weight loss or that these diets have benefits particular for metabolic health even if you do not lose weight.
“There is nothing special about fasting compared to standard diets”
“But intermittent fasting it is not a magic formula and the results of our experiment suggest that fasting nothing special compared to more traditional standard diets that can be followed, ” he warns. Most significantly, if you follow a fasting diet, it is worth considering whether prolonged fasting periods are making it difficult to maintain muscle mass and levels of physical activity, which are known to be very important factors for health. long-term”.
These results focused on participants who defined themselves as “lean” (ie, with a body mass index of 20-25 kg / m2). 36 people participated in the study that ran from 2018-2020 and was funded by the University of Bath.
Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.