Research

Energy balance

Sleep restriction (4-5 hours/night) increases 24-hour energy expenditure by ~5-7% in humans, but this metabolic cost is offset by a disproportionate increase in caloric intake (particularly from post-dinner snacks), resulting in a positive energy balance and weight gain.

If you are sleeping less than 7 hours, do not assume you are burning more calories and can eat more. Your body burns slightly more energy when awake, but your hormones (ghrelin/leptin) drive you to eat significantly more, especially late at night. This extra food intake outweighs the extra energy burned, leading to weight gain. Prioritize 7-9 hours of sleep to protect your metabolic health.

GoodSupportsHIGH confidence
When sleep is restricted in humans and food is provided ad libitum, participants have been shown to increase their food intake far beyond the amount of calories needed to meet the energy needs of extended wakefulness and thus enter a state of positive energy balance (16,42,43).
Andrew W. McHill et al. · Obesity Reviews · 2017

Why this rating

Based on multiple controlled human laboratory studies (e.g., Markwald et al., Spiegel et al.) with consistent findings, though duration is often short-term.

Source

Role of sleep and circadian disruption on energy expenditure and in metabolic predisposition to human obesity and metabolic disease

Andrew W. McHill et al. · Obesity Reviews · 2017

DOI 10.1111/obr.12503

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DOI resolved against Crossref · corpus check 2026-06-10

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