Ruiz’s team also observed that weight loss occurred regardless of when participants scheduled their eating window, suggesting that the approach offers considerable flexibility and can be adapted to fit individual lifestyles and routines.

“TRE offers a simplified and time-efficient alternative to traditional dieting. It eliminates the need for calorie counting and food tracking , which are common barriers to long-term adherence,” said lead investigator Jonatan R. Ruiz , PhD, professor in the department of Sport Sciences at the University of Granada.

While early research on TRE remains limited, new findings presented at the 32nd European Congress on Obesity in Malaga, Spain, on May 11–14, suggest it could be a useful strategy for improving long-term cardiometabolic health.

The goal is to reduce snacking and overall calorie intake by avoiding food outside the designated window.

Time-restricted eating (TRE) , a form of intermittent fasting , has gained popularity in recent years to aid weight loss. The idea is simple: instead of limiting what you eat, limit when you eat. Individuals who practice TRE typically choose a daily eating window of 8 to 12 hours.

New research suggests that a three-month protocol of time-restricted eating may help people with overweight and obesity lose weight and maintain that loss for at least one year.

The research builds on a previous randomized controlled trial of TRE conducted by the same team, with results published in Nature Medicine earlier this year. That study found that narrowing the eating window from 12 to 8 hours per day led to weight loss and improvements in cardiometabolic health.

The latest findings introduce a significant long-term follow-up period, offering insight into whether those health benefits are sustained over time. However, the research has not yet been submitted for peer-reviewed publication.

The study was a randomized controlled trial that followed 99 adults with overweight or obesity for 12 months in Granada, Spain. The cohort was evenly split between males and females, with an average age of 49.

Participants were randomly assigned to one of four groups for three months:

Habitual eating: Continued regular eating patterns, with a window 12 or more hours

Continued regular eating patterns, with a window 12 or more hours Early TRE: An 8-hour eating window starting before 10:00 a.m.

An 8-hour eating window starting before 10:00 a.m. Late TRE: An 8-hour eating window starting after 1:00 p.m.

An 8-hour eating window starting after 1:00 p.m. Self-selected TRE: Participants chose their own 8-hour eating window

All groups, including the habitual eating group, took part in a Mediterranean Diet education program.

After the 12-week intervention, all TRE groups lost significantly more weight than the habitual group — between 3.5% and 4.5% of body weight (about 8 pounds), compared to just 1.5% (3 pounds) in the habitual group.

Anthropometric measurements showed greater improvements in waist and hip circumference among the TRE groups. The early TRE group had the most substantial reductions, more than 1.5 inches at both sites. The late and self-selected groups saw similar, though more modest, changes. Meanwhile, the habitual group lost less than half an inch in either measurement.

The most notable results came during the 12-month follow-up, which assessed the durability of those outcomes. Once again, all three TRE groups outperformed the habitual group.

While the habitual group regained about one pound, participants in the TRE groups maintained modest weight loss. Both the early and late TRE groups sustained roughly 2% weight loss, and the self-selected group retained a 0.7% reduction.

Waist and hip outcomes varied by group. The late TRE group showed the greatest improvements, with more than two inches lost at the waist and 1.3 inches at the hips. In contrast, the habitual group gained roughly an inch around the waist. The early and self-selected TRE groups maintained reductions as well, but those changes were not statistically significant.

“Most prior studies on TRE have focused on short-term outcomes, often ranging from 4 to 12 weeks,” said Ruiz. “Our research provides one of the few datasets that includes long-term follow-up after the intervention, and it demonstrates that the initial weight loss benefits are largely maintained over time.”

Adherence rates — the proportion of individuals who were able to stick with the TRE protocol — were also noteworthy, ranging from 85% to 88%. Long-term adherence to any diet is often challenging, so these findings are promising for the potential of TRE.