intermittent fasting isn’t an effective weight-loss technique, according to the longest and most thorough study published on the topic.
the study, published wednesday in the
new england journal of medicine,
followed 139 patients considered obese over a period of one year. they were put on a calorie-restricted diet of 1200 to 1500 calories a day for women and 1500 to 1800 calories a day for men. the one significant difference was that one group was instructed to only eat between 8 a.m. and 4 p.m., while the other group could eat the same number of calories at any point during the day.
changes in weight ‘weren’t significant’
researchers found that after a full year of eating that way, “changes in weight were not significantly different in the two groups.” the group that just restricted calories lost a mean of 6.3 kg (14 pounds) while the time-restriction group lost 8 kg (18 pounds). there were also no major differences in waist circumferences, bmi, body fat, body lean mass, blood pressure, or other health markers like blood glucose levels or insulin sensitivity between the two groups.
“among patients with
obesity, a regimen of time-restricted eating was not more beneficial with regard to reduction in body weight, body fat, or metabolic risk factors than daily calorie restriction,” the researchers concluded.
fasting has a long history as a part of religious or political practices, but it became popular as a health and weight loss strategy within the last decade. there are a wide variety of kinds of fasts, from eating only between certain hours to taking several days off normal eating patterns. u.k. doctor michael mosley helped popularize the idea in the early 2010s with
the 5:2 diet
, which involves a cycle of eating normally for five days and then restricting calories to just 500 to 600 for two days.
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