The Study
Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index
This study found that people who sleep less tend to have different hunger hormones and are often heavier, but it doesn’t prove that sleeping less makes you fat — it just shows they go together, like how people who wear sneakers often run, but sneakers don’t make you run.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
When you don’t sleep enough, your body makes less of a hormone that tells you you’re full and more of one that tells you to eat.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 547 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — these changes are big enough to make people feel hungrier and gain weight over time.
- 25 hours of sleep vs.
- 38 hours: leptin down 15.5%, ghrelin up 14.9%, BMI up 3.6%.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
PLoS Medicine
Year
2004
Authors
Shahrad Taheri, Ling Lin, Diane Austin, Terry Young, Emmanuel Mignot
Related Content
Claims (6)
If you sleep less than 7.7 hours a night, the less you sleep, the higher your body mass index (BMI) tends to be — for example, people who sleep 5 hours have a 3.6% higher BMI than those who sleep 8 hours, even when you account for their age, gender, or breathing issues during sleep.
If you don’t get enough sleep just one night, your body makes more of the hunger hormone and less of the fullness hormone, which might make you feel hungrier the next day.
People who sleep only 5 hours a night tend to have lower levels of a hormone that tells your brain you're full, compared to those who sleep 8 hours — even if they're the same weight or age — which might make them feel hungrier.
If you only sleep 5 hours instead of 8, your body might produce more of a hormone that makes you feel hungrier — even if you’re the same weight, age, or sex as someone who sleeps longer.
When adults between 30 and 60 don’t get enough sleep over a long time, their body makes less of a hormone that tells them they’re full; but if they miss a night of sleep, their body makes more of a hormone that makes them feel hungry—so different kinds of sleep loss affect hunger in different ways.
For adults between 30 and 60, not getting enough sleep doesn’t seem to mess with blood sugar or insulin levels once you account for body weight—instead, it’s probably the hunger hormones that connect poor sleep to gaining weight.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.