If you have ever found yourself craving high-fat, high-calorie foods when you’re sleepy, it’s not your imagination: Sleep deprivation really does make you feel hungrier for junk food.
Doctors have long recommended adequate sleep as an important part of weight control. Studies have found that not getting enough sleep actually disrupts the hunger hormones ghrelin and leptin, causing overeating. More specifically, sleep deprivation increases ghrelin — an appetite stimulant — and decreases leptin, which helps control your appetite.
In other words, inadequate sleep means that you naturally feel hungrier, and and have less ability to control how much you eat.
That being said, these hormonal disruptions don’t entirely explain why we tend to reach for high-fat, high-carbohydrate junk foods when we’re sleep deprived. After all, being hungry doesn’t necessarily mean binging on cookies and cakes. Some foods can even help you achieve quality sleep. As it turns out, sleep deprivation related hunger is about a lot more than hormones.
Is A Lack of Sleep Equal to Smoking Marijuana?
If there’s one thing that almost everyone associates with smoking marijuana, it’s the munchies. For many people, marijuana spurs a desire to eat — and eat a lot. This is largely due to tetrahydrocannabinol (THC) in marijuana, which affects the endocannabinoid receptors in the brain responsible for appetite.
A team of European researchers discovered that some of these receptors are located in the brain’s olfactory bulb, which influences smell and taste, and concluded that marijuana makes you hungry because it heightens the smell and taste of food.
You might be wondering, though, what this has to do with sleep deprivation. As it turns out, the same endocannabinoid receptors that make you hungry when you use marijuana are also affected by sleep deprivation.
Researchers at Northwestern University’s Feinberg School of Medicine discovered elevated levels of the same receptors that are influenced by marijuana in 25 healthy adult subjects after they were limited to four hours of sleep. After this shortened rest period, subjects were allowed to eat whatever they wanted, and mostly chose foods higher in calories, fat, and carbohydrates.
What made the results even more interesting to the researchers were the subjects’ brain images, which revealed a higher level of activity in the piriform cortex after sleep deprivation. This is the part of the brain that helps process smells, leading the researchers to conclude that a lack of sleep causes people to process smells more strongly.
The brain scans also revealed that the connection between the piriform cortex and the insula, the part of the brain that controls appetite, was also influenced by the increased levels of endocannabinoids.
Brain images showed that there was less communication between the part of the brain that was processing the smell of food and the part that helps make food decisions. Researchers suspect that this reduced communication leads to eating higher fat foods, because your brain doesn’t have its normal influence on decision-making.
Ultimately, this research suggests that your brain’s response to sleep deprivation is similar to its response to using marijuana, at least in terms of food choices. It also means that when you find yourself drawn to the Cinnabon counter when you’re in the airport catching an early flight, or craving a greasy pizza while watching late night television, you probably can’t help it.
The Carbohydrate Connection
While these new discoveries about the connection between sleep deprivation, the endocannabinoid system, and food cravings show some promise for explaining the urge to pig out when we’re tired, there’s another factor that can’t be overlooked: Serotonin.
Serotonin is a neurotransmitter that’s commonly referred to as a “happy hormone.” In addition to helping produce feelings of happiness and well-being, serotonin helps regulate the sleep-wake cycle. Scientists suspect that while serotonin is mostly responsible for supporting wakefulness, producing too much of the chemical can actually cause sleepiness.
And because serotonin production is influenced by food, especially high carbohydrate foods, not getting enough sleep can make you eat more in order to stay awake.
Back in the 1990s, researchers at MIT discovered that the amount of serotonin the brain produces is directly related to food intake. More specifically, carbohydrate consumption increases serotonin production.
Because serotonin creates feelings of well-being, while also spurring the onset of sleep, many people turn to foods high in carbs and fats (like chips and pastries) simply because they make them feel good. These foods essentially become a drug, despite contributing to obesity, diabetes, and other health issues.
Serotonin isn’t only important for staying awake, though. The neurotransmitter is a precursor to melatonin, which also help regulate your sleep-wake cycle — more specifically, it helps you fall asleep.
So not only does your body crave carbohydrates so it can create enough serotonin to keep you awake, when you’re sleep-deprived, craving high fat foods is your body’s way of helping creating the serotonin necessary to fall asleep.
Maintaining a healthy diet is often recommended as a way to support healthy sleep patterns, but getting enough sleep is also important to maintaining a healthy diet. Because being tired can often be confused for hunger, instead of snacking on junk food late at night, head to bed instead. An intense desire for sugary, high-fat foods may simply be your body’s way of telling you that you need rest.