A groundbreaking meta-analysis suggests that when you eat may be just as important as what or how much you eat for metabolic health. Researchers analysed 41 randomised controlled trials involving around 2,200 participants, aged 19 to 69, tracked for 4 to 48 weeks. The studies compared early-time restricted eating (last meal before 5pm), mid-time (5-7pm), and late-time (after 7pm).
Key Findings
Eating earlier in the evening—finishing dinner before 5pm or 7pm—was linked to significant improvements in body weight, BMI, body fat percentage, waist circumference, blood pressure, and metabolic markers such as fasting glucose, insulin, and triglycerides. Importantly, these benefits occurred even when total calorie intake did not change.
Why Timing Matters
The body manages sugar better earlier in the day. Insulin secretion peaks between 12pm and 6pm and is lowest during sleep. Thus, the same meal causes a higher blood sugar spike at night. Eating earlier aligns food intake with the body's natural hormonal rhythms.
This challenges the simple 'calories in, calories out' narrative. Practical implications: if you crave chocolate cake, have it earlier in the day rather than after 5pm. However, modern lifestyles with late work and social commitments may make early dinners difficult. The key is to shift the eating window earlier when possible.
As Professor Devi Sridhar notes, 'I'm not saying have chocolate for breakfast, but if you're going to eat chocolate tomorrow, maybe have it before 5pm when your body's better primed to deal with it.'
