An 18-month clinical trial involving more than 200 adults with obesity found that intermittent fasting led to about the same average weight loss as continuous calorie restriction after six months, while participants on the fasting plan reported less need to constantly monitor or restrict their eating.
More than 200 adults with obesity took part in an 18-month clinical trial run by researchers at the University of Adelaide. Participants were randomly assigned to one of three groups: intermittent fasting, continuous calorie restriction, or standard care.
Those in the intermittent fasting group consumed about 30% of their daily energy needs between 8 a.m. and 12 p.m. on three non-consecutive days each week, then completed a 20-hour fast. On the remaining days, they ate their usual diet. The continuous calorie-restriction group consumed about 70% of their normal calorie intake each day, while the standard-care group continued their regular diets and received healthy eating guidelines.
After six months, the intermittent-fasting and continuous-calorie-restriction groups had each lost an average of about seven kilograms, compared with about two kilograms in the standard-care group.
"While many diets can result in weight loss, they may be difficult to stick to and this makes keeping that weight off long-term more challenging," said Professor Leonie Heilbronn of Adelaide University’s School of Medicine and the South Australian Health and Medical Research Institute. She added that the findings suggest intermittent fasting "could offer an alternative pathway for people who find conventional dieting challenging."
Researchers reported that participants following intermittent fasting did not feel they had to constantly monitor their eating, avoid overeating, or count calories to achieve similar weight loss—an experience that differed from those assigned to continuous calorie restriction.
The findings were published in the journal Clinical Nutrition. The researchers said psychological and behavioral factors can influence whether people adhere to diets, and called for future trials designed to identify which individuals may benefit most from each approach.
