Research

Hormonal

Short sleep duration (less than 6 hours per night) is associated with a significantly increased risk of developing obesity and weight gain in men over a 1-year period, whereas no such association was found in women.

If you are a man, getting less than 6 hours of sleep significantly increases your risk of becoming obese, even over just one year. This happens because short sleep lowers leptin (satiety hormone) and raises ghrelin (hunger hormone), driving you to eat more. Aim for 7-8 hours of sleep to protect your metabolic health. For women, the link to obesity is less clear in this study, but hormonal regulation still suggests sleep is important.

GoodQualifiesHIGH confidence
Short sleep duration was associated with weight gain and the development of obesity over 1 year in men, but not in women.
Mayumi Watanabe et al. · SLEEP · 2010

Why this rating

Large-scale prospective study (n=35,247) with 1-year follow-up, though limited by self-reported sleep data and lack of direct caloric intake measurement.

Source

Association of Short Sleep Duration with Weight Gain and Obesity at 1-Year Follow-Up: A Large-Scale Prospective Study

Mayumi Watanabe et al. · SLEEP · 2010

DOI 10.1093/sleep/33.2.161

cohort · n=34852Cited 259×
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DOI resolved against Crossref · corpus check 2026-06-10

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