Sutton 2018: Time-Restricted Eating Improves Insulin Sensitivity

Background

Dr. Elizabeth Sutton and colleagues from Pennington Biomedical Research Center published this RCT in Cell Metabolism (PMID: 29754952), testing early time-restricted feeding (eTRF) in men with prediabetes.

Study Design

Design: Randomized crossover trial Population: 8 men with prediabetes, BMI 30-39 Interventions:

• •eTRF: 6-hour eating window (8am-2pm), 18-hour fast
• •Control: 12-hour eating window (8am-8pm) Duration: 5 weeks each arm with 7-week washout Key feature: Isocaloric—same food, same calories, just timing differed

Key Findings

Metabolic improvements with eTRF (no weight change):

Parameter	eTRF Effect
Insulin sensitivity	+36% improvement
β-cell function	+10% improvement
Blood pressure	−10-11 mmHg
Oxidative stress	Significantly reduced
Evening appetite	Reduced

Critical finding: Benefits occurred WITHOUT weight loss—timing alone improved metabolism.

Mechanistic Insights

Time-restricted eating aligns food intake with circadian rhythms:

1. •Insulin sensitivity highest in morning
2. •Eating late disrupts peripheral clocks
3. •Extended fasting improves metabolic flexibility
4. •Allows completion of hepatic autophagy

Clinical Implications

Meal timing matters independent of calories. Early eating window (finishing by afternoon) more beneficial than late. May be practical intervention for prediabetes.

Metabolic Health Perspective

This study demonstrates that WHEN you eat matters, not just what or how much. For metabolic optimization, an early time-restricted eating pattern can improve insulin sensitivity without requiring weight loss.