Trial: Intermittent Fasting Matches Calorie Restriction
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- Adelaide University researchers ran an 18-month clinical trial with more than 200 adults with obesity, finding that intermittent fasting and continuous calorie restriction both produced average weight loss of about 7 kilograms at six months, versus roughly 2 kilograms for a standard-care group.
- Intermittent fasting participants consumed 30% of their daily energy needs between 8am and 12pm on three non-consecutive days each week, then completed a 20-hour fast; the calorie-restriction group ate about 70% of normal intake daily.
- Professor Leonie Heilbronn noted that fasting participants did not feel they had to constantly monitor eating, while the heightened sense of control reported by calorie counters accounted for roughly 15% of their weight loss.
- Participants in both active diet groups reported improvements in depression and overall well-being, including on fasting days, according to the study published in the journal Clinical Nutrition.
- Heilbronn said the findings suggest intermittent fasting and calorie restriction may promote weight loss through different psychological and behavioral mechanisms, and called for future trials to identify which individuals would benefit most from fasting for more personalized weight management.
Why it matters: For the more than 200 adults with obesity in this trial, intermittent fasting achieved the same ~7 kilogram weight loss as calorie restriction without the exhausting daily mental load of monitoring food — offering a practical alternative for the many people who abandon traditional diets because the constant self-control feels unsustainable.
