Effects of timing and eating duration of time restricted eating on metabolic outcomes: systematic review and network meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and network meta-analysis of randomized controlled trials
PubMed 41586347 · doi:10.1136/bmjmed-2024-001071
What was done
Systematic review and network meta-analysis of 41 randomized controlled trials comprising 2,287 participants evaluating time-restricted eating (interventions lasting >1 month) compared to usual diets or other time-restricted eating subtypes for metabolic health outcomes. Subtypes were categorized by timing of the last meal (early: <1700; mid: 1700–1900; late: >1900; or self-selected) and duration of the daily eating window (<8 hours, 8 hours, >8 hours). Risk of bias was assessed with the RoB 2 tool and evidence certainty with CINeMA.
What was found
Overall time-restricted eating improved body weight, BMI, fat mass, waist circumference, systolic blood pressure, fasting blood glucose, fasting insulin, and triglycerides compared with usual diets (specific effect sizes not reported in the abstract). Early time-restricted eating showed higher P score rankings for anthropometric measurements (range 0.62–0.86, excluding fat-free mass) and glycemic parameters (range 0.66–0.99). Compared directly to late time-restricted eating, early time-restricted eating significantly reduced body weight (mean difference -1.15 kg, 95% CI -1.86 to -0.45) and fasting insulin (-3.32 μIU/mL, 95% CI -5.36 to -1.28; high certainty). Rankings for eating window duration were inconsistent. Most trials (90%) had low risk of bias, and 60.2% of network comparisons showed moderate-to-high certainty.
Why it matters
These findings suggest that the timing of the eating window matters more than its exact duration, with earlier eating windows providing superior glycemic and weight benefits compared to later windows.
Limits
Numeric effect sizes and confidence intervals for overall time-restricted eating versus usual diet were not reported in the abstract. Approximately 39.8% of the network evidence had low or very low certainty, and eating duration showed inconsistent effects.
Cited by
- supports Human studies on time-restricted eating comparing a breakfast-plus-lunch feeding window to a lunch-plus-supper window show superior metabolic outcomes when meals are eaten earlier in the day.