People with excess weight who eat all their meals before 4 p.m. while cutting calories experience a larger drop in leptin—a hormone linked to fullness—than those who eat the same calories later in the day or over a longer window.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Whether early TRE consistently reduces leptin levels more than other eating patterns across diverse populations, independent of fat mass loss.
A systematic review and meta-analysis of 15 RCTs (n≥800 total) comparing early TRE (≤10 h window ending by 16:00) with ER or late TRE in adults with overweight/obesity, measuring fasting leptin as primary outcome, with adjustment for fat mass change.
Whether early TRE directly suppresses leptin secretion independent of fat mass reduction.
A double-blind, crossover RCT with 40 adults (BMI 28–34) undergoing two 8-week phases: early TRE (8:00–16:00) and late TRE (12:00–20:00), with identical 500 kcal/day deficit and weight loss matched via caloric adjustment, measuring leptin every 4 hours over 24 h at baseline and endpoint.
Whether habitual early eating predicts lower leptin levels over time in adults with obesity, independent of weight change.
A 3-year prospective cohort of 1,200 adults with obesity (BMI ≥30) tracking daily eating windows via app logs, measuring fasting leptin annually, adjusting for fat mass, sleep, and physical activity.
Whether individuals with greater leptin reduction after early TRE show altered adipocyte circadian clock gene expression compared to those with minimal change.
A case-control study comparing 25 participants with >30% leptin reduction and 25 with <10% reduction after 12 weeks of early TRE, measuring adipose tissue biopsies for PER2, BMAL1, and leptin receptor expression.
Whether adults who habitually eat earlier have lower leptin levels than those who eat later, matched for body fat percentage.
A cross-sectional study of 800 adults (BMI 25–35) using 7-day food logs and actigraphy to classify eating timing, measuring fasting leptin, adjusting for fat mass, age, sex, and sleep duration.