The study examined not only how much weight people lost, but also how different dieting approaches affected eating habits, mood, sleep, and overall quality of life.

Researchers found that intermittent fasting and continuous calorie restriction produced similar weight loss. However, participants following the fasting plan did not feel they had to constantly monitor their eating, avoid overeating, or count calories to achieve those results.

Different Mental Approach to Weight Loss

That experience differed from people following a calorie restricted diet. Those participants reported that losing weight required ongoing effort to consciously limit how much they ate and resist overeating. Researchers estimated that this increased sense of control accounted for about 15% of their weight loss.

“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 from Adelaide University’s School of Medicine and the South Australian Health and Medical Research Institute.

“The results of our study indicate intermittent fasting could offer an alternative pathway for people who find conventional dieting challenging.”

How the Study Compared Three Diet Plans

More than 200 adults with obesity took part in the 18 month clinical trial. Participants were randomly assigned to one of three groups: intermittent fasting, continuous calorie restriction, or standard care.

Those in the intermittent fasting group consumed 30% of their daily energy needs between 8am and 12pm on three non consecutive days each week. After that eating window, they completed a 20 hour fast. On all other days, they ate their usual diet.

Participants assigned to continuous calorie restriction consumed about 70% of their normal calorie intake each day. The standard care group continued their regular diets but received healthy eating guidelines.

Similar Weight Loss, Different Experience

After six months, participants in both the intermittent fasting and calorie restricted groups had lost an average of about seven kilograms. By comparison, those receiving standard care lost only about two kilograms.

People in both dieting groups also reported improvements in depression and overall well being, including on fasting days.

The findings, published in the journal Clinical Nutrition, suggest that intermittent fasting and calorie restriction may promote weight loss through different psychological and behavioral mechanisms.

“Psychological and behavioral effects have a major influence on people’s abilities to adhere to diets. Intermittent fasting may help people achieve weight loss through ways that are less dependent on consciously restricting intake,” said Professor Heilbronn.

Why Researchers Want to Study Intermittent Fasting Further

Although intermittent fasting has grown rapidly in popularity, researchers say much remains unknown about its long term psychological and behavioral effects compared with more traditional dieting strategies.

“Future trials should be designed to identify individuals who struggle to improve eating behaviors, as they may do better with intermittent fasting diets, enabling more personalized weight management,” said Professor Heilbronn.