We count calories and steps, and forget the factor that quietly undermines all of it: your hours of sleep.
What do the numbers say?
A meta-analysis of prospective cohort studies covering 285,452 adults found that short sleep — and long sleep too — significantly raises the risk of weight gain, with short sleep specifically raising obesity risk[1]. Other meta-analyses estimated the odds ratio for obesity with short sleep at 1.45 and 1.55 — a risk increase of roughly 45–55%[2],[3]. A recent systematic review (2024) linked short sleep specifically to higher risk of central obesity (abdominal fat)[4].
(odds ratio 1.55)
meta-analysis
central obesity specifically
Why? Not just "staying up and snacking"
Studies point to hyperactivation of the hypothalamic-pituitary-adrenal axis with insufficient sleep, raising cortisol and contributing to body fat accumulation[5] — meaning your body stores more even if you eat the same amount.
We stay up later than most
Our social culture is built around the night: gatherings after dinner, weekend rest houses, and workdays that start early. The result is fragmented short sleep six nights a week, then "catch-up" at the weekend — and the body does not run on a catch-up system.
What actually works?
- Fix your wake time, not your bedtime: your body clock is set by the morning, not the night.
- Majlis coffee needs a cut-off hour: caffeine stays active for hours — a late-evening cup is not innocent.
- Phone out of the bed: the simplest intervention and, in practice, the most effective.
- Don't compensate with a long nap: a 20–30 minute nap refreshes; two hours steal your night's sleep.