Various strategies to reduce overweight and obesity exist such as dietary modifications, weight reduction medication and metabolic and bariatric surgery. Among the dietary modifications a new approach called time-restricted feeding (TRF) has surged. TRF implies a diet with an ad libitum energy intake within specific time frames during a 24-hour period inducing extended fasting intervals.
The study was registered in PROSPERO. An extensive literature review was performed in various databases: PubMed, ScienceDirect, Cochrane Library, SCOPUS, and Web of Science. We included all randomized controlled trials, controlled trials, cross-over studies and pre-post studies that specified feeding schedule, did not pertain to Ramadan fasting, and aimed to have an effect on weight.
Eleven studies met the inclusion criteria, with a 14-week mean follow-up period and feeding windows ranging from 8-13h, except for one study that had a 3h reduction. A total of 277 participants were identified of which 34 were resistance trained males and 28 recreationally active men. Mean weight at baseline was 81.75 kg. The calculated mean percentage weight loss of studies with significant outcome was -1.7%. Seven studies that reported fat-mass the mean significant percentage change was calculated to be –6.3%. Overall, quality of the evidence ranged from low to moderate.
TRF compared to a normal diet causes a reduction on weight and fat-mass with a greater effect on the latter. Nonetheless the effects observed need well-designed long-term studies with and without association of exercise to evaluate the consistency of effect of TRF on weight and fat-mass.