Anyone who’s woken up at 3 a.m. with their stomach growling has probably wondered, what gives? Is it even normal to be this hungry at this hour? Hunger levels, which are regulated in part by our circadian rhythms, generally rise throughout the day, are highest in the evening, and decline throughout the night and into the morning. So if you’re getting up in the dead of night with major hunger pangs, experts say it’s worth investigating.
“Sleep drive can be quite strong, so if the brain/body is waking in the middle of a sleep period because of hunger, that would indeed suggest that something was ‘off,’” Erin Hanlon, a behavioral neuroscientist at the University of Chicago, told HuffPost.
Sleep and circadian scientist Kristen L. Knutson, an associate professor at Northwestern University, agreed that it’s “unusual” to wake up hungry mid-slumber “because our internal biological clocks do not expect us to be eating at this time.”
Waking up for a midnight snack every once in a while probably isn’t anything to be concerned about. But if nocturnal noshing has become a more regular pattern — and an annoying one at that — then you may be looking for answers.
We talked to experts to understand why this might be happening and what you can do about it.
Reasons you could be waking up hungry.

You’re not eating enough during the day.
If you’re not consuming enough calories during the day, then you may find yourself waking up with a rumbling stomach in the middle of the night. Suppose you’re dieting or restricting in any way, like skipping meals or over-exercising. In that case, you may not be eating enough calories,” said registered dietitian Alissa Rumsey, the author of “Unapologetic Eating.” Keep in mind that any increase or change in your usual physical activity — like, say, training for a race or starting a new workout routine — could be playing a role, too. Depending on how intense this exercise regimen is, you may need to eat a little more to refuel properly.