A study published in the Journal of the American Medical Association explored the effects of time-restricted eating (TRE), meal frequency, and calorie distribution on anthropometric and metabolic measures, gathering results from multiple randomized controlled trials (RCTs). It includes data from 17 RCTs on TRE, 5 on meal frequency, and 4 on calorie distribution, with a total of 2,227 participants across these studies. The overall findings suggest that TRE has moderate effects on weight loss, body mass index (BMI), lean mass, and waist circumference, with further associations found between TRE and metabolic markers like HbA1c, fasting glucose, LDL cholesterol, and energy intake.
Participants with higher baseline BMI tended to experience greater weight loss compared to those with a lower BMI, indicating that the benefits of TRE may be more pronounced in individuals who are overweight or obese. When the TRE regimen had feeding windows of 8 hours or less, participants lost more weight than those who ate within longer windows, suggesting a potential dose-response effect for shorter eating windows.
In terms of metabolic measures, TRE showed modest reductions in HbA1c and fasting glucose, indicating some potential benefits for individuals at risk of type 2 diabetes. However, these reductions were of low clinical significance and were accompanied by substantial heterogeneity. On top of this, TRE was associated with small reductions in LDL cholesterol, which could be beneficial for cardiovascular health.
The analysis of meal frequency included five RCTs and found that lower meal frequency was associated with a modest reduction in weight (mean difference, –1.84 kg) and BMI (mean difference, –0.65). Interestingly, no clear association was found between meal frequency and lean mass or waist circumference, suggesting that while fewer meals may impact overall weight, it does not significantly alter body composition.
The study suggests that while TRE appears to offer some benefits in terms of weight loss, BMI reduction, and metabolic health markers, these effects are generally modest, with significant variability across different participants and study designs.
