Long-Term Benefits of 16-Hour Fasting Achieved Regardless of Eating Window Timing

Recent findings from a randomized controlled trial presented at the European Congress on Obesity highlight that a 16-hour fasting window can promote sustained weight loss for at least one year, regardless of whether the eating window occurs earlier or later in the day. The study involved 99 adults with overweight or obesity from Granada, Spain, who were assigned to different groups based on their eating schedules: a habitual 12-hour or longer window, an early 8-hour window starting before 10:00, a late 8-hour window starting after 13:00, and a self-selected 8-hour window.

All participants received education on the Mediterranean diet to encourage healthier eating habits. After a 12-week intervention, those practicing time-restricted eating (TRE), which limits the daily eating period but not caloric intake, experienced significantly greater weight loss—ranging from approximately 3.1 to 4.2 kg—compared to the habitual eaters, who lost around 1.4 kg. TRE groups also showed notable reductions in waist and hip circumferences.

Remarkably, at the 12-month follow-up, participants who engaged in TRE maintained their weight loss and reduced body measurements more effectively than those who continued with habitual eating patterns. The early and late TRE groups preserved an average weight loss of just over 2%, while the habitual group experienced a slight regain, averaging 0.4 kg. Waist and hip circumferences remained lower in the TRE groups, indicating the long-term benefits of this fasting approach.

Participants generally found TRE acceptable, with adherence rates between 85% and 88%, and no serious adverse events were reported. Experts suggest that the simplicity and flexibility of time-restricted eating may offer a practical, sustainable strategy for weight management among individuals with overweight or obesity.

This study underscores that maintaining a consistent 16-hour fast can support long-term weight loss and health benefits, independent of specific eating window timing, paving the way for more personalized and manageable dietary strategies.