Not getting enough z’s can make you irritable, unproductive, and extremely cranky. Very often, an order of a family-sized pizza with soda and fries just for yourself or an unvanquishable craving for a 5-scoop sundae at noon accompanies these poor sleep symptoms.
Science tells us that it’s not just boredom or not knowing what else to do with your unproductive self that is driving you toward these unhealthy foods. There is more to it.
Lack Of Sleep Makes You Crave Junk Foods
Sleeping less, mostly than 6 hours a night, has been linked to weight gain for some time now. Consumption of energy-dense foods has been blamed for this. One theory is that late-night snacking can deprive your body of the time it needs to digest food, causing it resort to a quick fix and store most of the food as fat.
Here are two other theories that are doing their rounds among the white coats:
1. Lack Of Sleep Causes You To Indulge In Pleasure Eating
Certain parts of the brain are more evolved and participate in complex decision-making while other parts still function on basic primal instincts.
A 2013 study showed that when you don’t get enough shut-eye, the brain regions that help you make complicated, well-informed decisions become dulled – which is why you feel brain-fogged and are unable to think straight after a late night.1
On the other hand, lack of sleep activates the more primal regions of the brain like those that control motivation and desire, the reward centers. Because of this, the cravings for food are increased with preference given to those most capable of triggering weight gain – high-calorie foods (read: junk foods). These foods are, in effect, seen as rewards by your brain.
Another theory is that your sleep-deprived brain craves high-calorie foods to make up for the energy spent staying up long hours. While this theory seems legitimate, it was also noticed that individuals tend to consume calories much higher than those spent staying up.
The extent of your cravings will depend on how sleep deprived you are. The poorer your sleep, the more you crave junk foods.
Building on previous findings and delving deeper, a 2016 study showed the molecular mechanisms at play when you crave junk foods as a result of not sleeping well.2 These mechanisms were much like the appetite-reward systems at work when you smoke marijuana: the endocannabinoid (eCB) system involved in regulating appetite and energy levels.
2. Lack Of Sleep Increases Your Brain’s Sensitivity To Food Smells
At the Cognitive Neuroscience Society’s annual meeting in San Francisco in March 2017, researchers claimed that the lack of sleep also makes you more sensitive to food smells.3
In their study, brain activity was monitored in two settings: (1) after participants slept for only 4 hours and were in a sleep-deprived state and (2) after they slept a complete 8 hours and were well rested.
The participants were more sensitive to food odors such as those from potato chips and cinnamon rolls in a sleep-deprived state than when they were fully rested. In the sleep-deprived state, two areas of the brain involved in olfaction (the sense of smell) were seen to be more active than in the well-rested state. These were the posterior orbitofrontal cortex and the piriform cortex. Such brain activity was not seen in response to non-food odors.
This study suggests that while you may be able to exert self control when you see a slice of cake after a good night’s sleep, you may not be ale to do so when you are running on low battery after getting inadequate sleep. The very smell of a calorie-laden food can cause you to let your guard down.
You can trick your brain into believing you are well rested and maintain your A-game throughout the day despite poor sleep. However, this will not work for chronic lack of sleep.
It is so important to know that you are more vulnerable to weight gain if you don’t sleep well – thanks to your brain’s smell sensors and reward centers taking over. That way you can make a conscious effort to calm your cravings.
|↑1||Greer, Stephanie M., Andrea N. Goldstein, and Matthew P. Walker. “The impact of sleep deprivation on food desire in the human brain.” Nature communications 4 (2013): 2259.|
|↑2||Molecular ties between lack of sleep and weight gain. National Institutes of Health.|
|↑3||Central olfactory mechanisms underlying sleep-dependent changes in food processing. The Journal of Cognitive Neuroscience.|