Effects of 4- and 6-h Time-Restricted Feeding on Weight and Cardiometabolic Health: A Randomized Controlled Trial in Adults with Obesity.
Level 2 - randomized trial
Individual randomized controlled trial in humans
PubMed 32673591 · doi:10.1016/j.cmet.2020.06.018
What was done
Adults with obesity were randomized to one of three parallel groups for 8 weeks: 4-hour time-restricted feeding (eating between 3:00 p.m. and 7:00 p.m.), 6-hour time-restricted feeding (eating between 1:00 p.m. and 7:00 p.m.), or a control group with no meal timing restrictions. Outcomes assessed included body weight, energy intake, insulin resistance, and oxidative stress.
What was found
After 8 weeks, both the 4-hour and 6-hour time-restricted feeding groups achieved comparable reductions in body weight (~3%) and spontaneous energy intake (~550 kcal/day, without calorie counting) compared to controls. Both intervention groups also demonstrated reductions in insulin resistance and oxidative stress relative to controls. Specific numerical values, standard deviations, and p-values for cardiometabolic endpoints were not reported in the abstract.
Why it matters
This trial directly compares 4-hour versus 6-hour daily eating windows, showing both regimens achieve similar modest weight loss and spontaneous caloric restriction without active calorie counting.
Limits
The abstract does not report sample size (n), baseline participant characteristics, dropout rates, or exact numerical values and confidence intervals for insulin resistance and oxidative stress. The 8-week duration is too short to establish long-term weight maintenance or metabolic sustainability.
Cited by
- context A 6-hour time-restricted feeding study conducted by Krista Varady's group showed blood pressure reductions comparable in effect size to antihypertensive medications when calories were equated.