Study Suggests Intermittent Fasting Is Simpler Than Calorie Counting for Weight Loss

What if losing weight didn’t require counting every calorie? A new study suggests intermittent fasting may make weight loss feel easier to stick with.

Researchers from the University of Adelaide found that intermittent fasting helped people lose weight just as effectively as traditional calorie restriction, while requiring less mental effort to control eating. The findings, published in Clinical Nutrition, suggest fasting could be a practical option for people who struggle with constant calorie counting.

The 18-month clinical trial involved more than 200 adults with obesity, who were randomly assigned to one of three groups: intermittent fasting, continuous calorie restriction, or standard care.

Participants in the intermittent fasting group consumed 30% of their daily calorie needs between 8 a.m. and 12 p.m. on three non-consecutive days each week, followed by a 20-hour fast. On the remaining days, they ate their usual diet. Those in the calorie-restriction group consumed about 70% of their normal daily calorie intake, while the standard care group received healthy eating advice without specific calorie limits.

After six months, both the intermittent fasting and calorie-restriction groups lost an average of about 7 kilograms, compared with only 2 kilograms in the standard care group.

However, researchers found an important difference in participants’ experiences. People following intermittent fasting reported they did not feel the need to constantly count calories, monitor food intake, or resist overeating. In contrast, those on continuous calorie restriction said maintaining weight loss required ongoing effort and self-control. Researchers estimated this increased mental effort accounted for about 15% of the weight loss seen with calorie restriction.

The researchers say intermittent fasting may work through different psychological and behavioral mechanisms, making it easier for some people to maintain long-term. They recommend further studies to identify who may benefit most from this approach to weight management.

REFERENCE: Xiao Tong Teong, Kai Liu, Andrew D. Vincent, Bo Liu, Gary A. Wittert, Amy T. Hutchison, Leonie K. Heilbronn. Exploring the impact of intermittent fasting plus time-restricted eating versus calorie restriction on eating behavior, mood, sleep, quality of life in adults with obesity. Clinical Nutrition, 2026; 62: 106686 DOI: 10.1016/j.clnu.2026.106686