Sleeping less often means eating more. In surveys and experimental studies, the Zzz-less tend to come off as hungrier and less able to suppress their drive for a nacho cheesier life than people who hit their nightly snoozing quota. The link between sleep deprivation and weight gain isn't limited to any single group — reports of staying up and sizing up have emerged across age, geographic coordinates and gender. But, while data suggests that women often struggle with weight gain more than men, it's possible that men are more prone to packing on pounds when they don't hit the sack. Researchers from the University of Arizona and Harvard Medical School presented their not-yet-published findings last month at the 2016 American Association of Sleep Medicine (AASM) SLEEP conference.
It's thought that a few changes in brain activity underlie the mighty appetites and feeble willpower observed during periods of sleep loss. For one thing, the pre-frontal cortex, the brain's logical-thought center, is supposed to regulate levels of neurotransmitters involved in processing hunger. During sleep deprivation, however, the pre-frontal cortex slacks off, leaving brain chemicals prone to running wild. Still, we don't understand a lot of what throws certain sleep-deprived brains off kilter but not others.
Previously, researchers have observed an uptick in levels of the neurotransmitter GABA following shuteye-free nights. So, the current researchers sought to explore the relationship between not sleeping, feeling hungry and GABA. They recruited 45 adults to stay awake for 29 hours and periodically rate their levels of hunger. Researchers measured participants' levels of GABA, both before and during the study, and kept tabs on their calorie intake. Compared to female participants, men consumed more calories and reported higher levels of hunger. Researchers were able to link hunger with baseline levels of GABA — but only for men. In other words, men whose brains coursed with GABA from the get-go felt more famished when they didn't sleep. Women's GABA levels didn't predict complaints about empty bellies.
The preliminary results support the idea that sleep deprivation hits men where it hurts — their waistlines — and goes on to suggest that susceptibility to weight gain may partially hinge on differences in GABA levels. The findings don't in any way explain individual differences in weight gain in underslept women.