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.

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.

If you don’t get enough sleep for 8 days, your hunger hormones don’t change much—so if you end up eating more, it’s probably not because these hormones are telling you to.

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.

Eating early in the day lowers two key hormones (leptin and GLP-1) in the morning, which may reflect the body’s natural rhythm adjusting to food timing.

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.