Neuroscience News & Research
A new study suggests that the popular dietary technique intermittent fasting (IF) is less effective that traditional daily dieting at reducing body fat. What is intermittent fasting? IF has become a well-known dietary plan in the Western world. The calorie restriction technique has been boosted by celebrity practitioners ranging from the Tonight Show host Jimmy Kimmel to Twitter CEO Jack Dorsey. IF is an umbrella term for various planned eating schedules: some routines dictate not eating between certain hours of the day, while the 5:2 diet, popularized over the last decade, mandates a heavily restricted diet for two days of the week. Despite IF’s popularity, its health benefits remain unclear. Advocates suggest that IF should stimulate evolutionarily conserved mechanisms that could help burn fat. Studies conducted in mice have shown clear metabolic benefits from restricted food availability in certain periods. Small studies in humans have repeatedly shown that improvements to insulin sensitivity, a metabolic marker that can protect against diabetes, can be realized with just a few weeks of IF. Nevertheless, a review article from the National Institute on Aging points out that large scale studies of fasting remain scarce and that calorie restriction diets should be clinically monitored. In a new study, researchers led by the University of Bath’s Professor James Betts examined the effects of a type of IF called alternate day fasting, where calorie intake is reduced every other day. They wanted to discover whether alternate day IF would have health benefits in humans, and, importantly, whether those benefits would go above and beyond any improvements seen through normal daily calorie restriction. To do so, they designed a first-of-its-kind trial.
The authors recruited study participants who were all lean and of healthy weight – most IF studies look at people who are overweight. For three weeks, 36 volunteers were separated into three equal groups:
