A new study presented at the European Congress on Obesity (ECO) in Malaga, Spain, suggests that three months of time-restricted eating (TRE) could be a promising strategy for sustaining long-term weight loss in adults with overweight or obesity.
The research found that limiting the daily eating window to eight hours, regardless of whether it's earlier or later in the day, can result in significant weight loss that lasts for at least a year. These benefits are attributed to the 16-hour fasting period rather than the specific timing of meals.
Time-restricted eating is an increasingly popular intermittent fasting approach that focuses on when people eat, not what they eat. Unlike low-calorie diets—which are known to aid weight loss and improve cardiometabolic health but often suffer from low long-term adherence—TRE may offer a more sustainable option.
In a previous trial published in *Nature Medicine*, the same research team discovered that reducing the eating window from 12 hours or more to eight hours per day decreases body weight and improves cardiometabolic health. However, the impact of eating window timing on long-term weight maintenance was still unknown.
To explore this, researchers conducted a 12-month follow-up study involving 99 adults with overweight or obesity from Granada, Spain. The participants, half of whom were women, had an average age of 49 years and an average body mass index (BMI) of 32 kg/m².
Participants were randomly assigned to one of four groups for 12 weeks:
- Habitual eating window of 12 hours or more.
- Early TRE: 8-hour eating window starting before 10:00 a.m.
- Late TRE: 8-hour eating window starting after 1:00 p.m.
- Self-selected TRE: participants chose their own 8-hour eating window.
All groups took part in a Mediterranean diet education program to encourage healthier eating habits.
Measurements of body weight, waist circumference, and hip circumference were taken at the start, after the 12-week intervention, and 12 months later. After the intervention, the habitual eating group experienced an average weight loss of 1.4 kg (1.5%). In contrast, all TRE groups achieved significantly greater weight loss:
- Early TRE group: average weight loss of 4.2 kg (4.5%).
- Late TRE group: average weight loss of 3.1 kg (3.5%).
- Self-selected TRE group: average weight loss of 3.8 kg (3.9%).
Reductions in waist and hip circumferences were also more pronounced in the TRE groups. The early TRE group saw average reductions of 4.1 cm in waist circumference and 4.6 cm in hip circumference. The late TRE group had a significant reduction in waist circumference (4.1 cm) and a reduction in hip circumference (3.2 cm). The self-selected TRE group showed reductions of 3.7 cm in waist circumference and 3.6 cm in hip circumference.
Twelve months after the intervention ended, the habitual eating group had an average weight gain of 0.4 kg (0.5%). Both the early TRE and late TRE groups maintained significantly greater weight loss compared to the habitual eating group:
- Early TRE group: maintained average weight loss of 2.2 kg (2.1%).
- Late TRE group: maintained average weight loss of 2.0 kg (2.0%).
Waist and hip measurements remained lower in the late TRE group compared to the habitual eating group. The late TRE group had average reductions of 5.6 cm in waist circumference and 3.4 cm in hip circumference.
Dr. Jonatan R. Ruiz, the study coordinator from the University of Granada, commented, "This kind of intermittent fasting appears feasible for adults with overweight or obesity who wish to have a relatively simple way of losing and maintaining weight loss that is less tedious and more time-efficient compared with daily calorie counting, but it warrants further investigations in larger and longer-term studies."
TRE was well accepted by participants, with adherence rates between 85% and 88%. No serious adverse events were reported during the 12-week intervention, and only five participants experienced mild adverse events, choosing to discontinue the intervention.
The study indicates that a simple three-month TRE lifestyle intervention may be an effective long-term approach for sustaining weight loss, regardless of the timing of the eating window.
The article was written with the assistance of a news analysis system.