Effect of Isocaloric, Time-Restricted Eating on Body Weight in Adults With Obesity : A Randomized Controlled Trial.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 38639542 · doi:10.7326/M23-3132
What was done
In a 12-week randomized isocaloric feeding study at a clinical research unit, 41 adults with obesity and prediabetes or diet-controlled diabetes were assigned (1:1) to either time-restricted eating (10-hour window, 80% of calories before 1 p.m.) or a usual eating pattern (≤16-hour window, ≥50% of calories after 5 p.m.). Diets were isocaloric and matched for nutrient content based on baseline requirements. The primary outcome was 12-week body weight change; secondary outcomes included fasting glucose, HOMA-IR, oral glucose tolerance test glucose area under the curve, and glycated albumin.
What was found
All 41 participants completed the study. Baseline weight was 95.6 kg (95% CI, 89.6 to 101.6 kg) in the time-restricted group and 103.7 kg (95% CI, 95.3 to 112.0 kg) in the usual eating group. At 12 weeks, weight decreased by 2.3 kg (95% CI, 1.0 to 3.5 kg) with time-restricted eating and by 2.6 kg (95% CI, 1.5 to 3.7 kg) with the usual eating pattern (mean difference, 0.3 kg [95% CI, -1.2 to 1.9 kg]). Glycemic measures showed no significant differences between groups.
Why it matters
This trial demonstrates that the weight-loss benefits associated with time-restricted eating are likely mediated by spontaneous caloric restriction rather than the timing of food intake itself.
Limits
The study had a small sample size (n = 41), was conducted at a single site, and had baseline weight differences between groups. The sample was predominantly female (93%) and Black (93%), which may limit generalizability.
Cited by
- supports When calories are equated, the weight loss benefits of time-restricted eating are no longer observed.