Why do we feel hungry during periods throughout the day, yet we can go a full night of sleeping without being woken up by hunger pangs?
According to a new study in the Journal of Neuroscience, it's because nerves in our gut that signal "fullness" to the brain really do work like clockwork.
In experiments with mice, researchers from the University of Adelaide found that these nerves are least sensitive during periods of wakefulness. This means that during times when we're expending more energy (which is when we're awake), we are able to consume more food before we feel full.
"However, with a change in the day-night cycle to a period associated with sleeping, the nerves in the stomach become more sensitive to stretch, signaling fullness to the brain quicker and thus limiting food intake," study researcher Dr. Stephen Kentish, of the Nerve-Gut Research Laboratory at the university, said in a statement.
"This variation repeats every 24 hours in a circadian manner, with the nerves acting as a clock to coordinate food intake with energy requirements," he added.
While the discovery was only found in mice, researchers said they theorize that similar nerve responses also exist in humans.