For people who struggle to maintain a diet, the problem may not be willpower — it may be the method. A new clinical trial from the University of Adelaide found that intermittent fasting produces weight loss similar to daily calorie restriction, but with far less of the mental burden that often causes diets to fail.
The 18-month study followed more than 200 adults with obesity, who were randomly assigned to one of three groups: intermittent fasting, continuous daily calorie restriction, or standard care. The fasting group ate only 30 percent of their daily energy needs between 8 a.m. and noon on three non-consecutive days each week, followed by a 20-hour fast, while eating normally on the remaining days.
Both the fasting group and the calorie-restriction group lost comparable amounts of weight over the course of the study, the researchers found. But the two approaches felt very different to the people living through them. Participants in the calorie-restriction group reported needing to consciously monitor their intake, resist overeating, and stay in a constant state of self-restriction. Those following the fasting protocol did not report the same ongoing psychological load.
The findings, published in the journal Clinical Nutrition, examined more than just the number on the scale — researchers also tracked eating behavior, mood, sleep, and overall quality of life across both approaches. Notably, intermittent fasting was not linked to worse mood or quality of life compared to daily restriction, addressing a common concern that periodic fasting might be harder to tolerate psychologically.
Researchers say the results matter because long-term success with any diet depends less on which plan produces faster results and more on which plan a person can actually sustain. As the study’s authors note, the hardest part of weight loss is often not losing the weight in the first place, but continuing the approach long enough for it to matter. For people who find daily calorie tracking exhausting or demoralizing, intermittent fasting may offer a comparably effective path that’s easier to live with over time.
