Intermittent fasting helped people keep weight off for a year
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- University of Granada researchers found that 99 adults with overweight or obesity who limited daily eating to an 8-hour window kept significantly more weight off one year later than participants who continued eating across 12 or more hours
- The study, published in Clinical Nutrition, tested early (9 a.m.–5 p.m.), late (1 p.m.–9 p.m.), and self-selected 16:8 eating windows and found all three time-restricted groups maintained lasting weight-loss benefits regardless of timing
- Early-day fasting was especially effective at preserving fat mass loss, even though overall weight maintenance was comparable across early and late windows
- Roughly one in three participants chose to keep practicing intermittent fasting on their own during the year of follow-up, which researchers cited as evidence the habit is sustainable outside clinical supervision
- An earlier Nature Medicine paper from the same project showed time-restricted eating participants lost 3–4 kilograms more than people receiving Mediterranean-diet nutritional guidance alone, regardless of eating-window timing
- Dr. Alba Camacho Cardeñosa of the University of Granada's iMUDS institute is first author of the new paper; Professor Jonatan Ruiz Ruiz leads the PROFITH CTS-977 research group that conducted the work alongside ibs.GRANADA and CIBER collaborators
Why it matters: The findings turn time-restricted eating from a short-term weight-loss tactic into a candidate for medium-term weight management: 99 study participants retained measurable benefits a full year after the 12-week program ended, and one-third kept fasting voluntarily. Clinicians now have evidence that the 8-hour window — and especially an early one — can be prescribed with reasonable confidence it will hold up outside a trial.
