Lack of Sleep Causes Terrible Food Cravings

By now it seems fairly clear that a lack of sleep can cause you more harm than just dozing off at your desk. It can change your insulin resistance, brain function, and weight gain.


However, until recently, the exact reason why you would gain weight was unknown. Some simply said that you spent more hours awake, so you had more time to eat. A new study shows that it’s actually so much more than that. A lack of sleep encourages the brain to look for (and eat, of course) sweet and fatty goods.

Photo credit: bigstock

Photo credit: bigstock

When we are walking around with those bleary eyes, the part of the brain that is connected to seeking rewards and addictive behavior goes through a dramatic chemical change. This section of your brain is called the nucleus accumbens, and it controls our desire to eat for pleasure, rather than out of hunger.

This study, which was done by researchers at University of California at Berkeley, showed that spending a late night watching Twilight Zone marathons can cause you to seek out junk food, rather than healthy foods.

This study involved 23 young adults whose brains were scanned using an fMRI (functional magnetic resonance imaging). The subjects were scanned after a normal night of sleep and then again after a night with very little sleep. The two scans were compared and, following a sleepless night, the researchers discovered that the brains frontal lobe activity was reduced. Not only that, the researchers found that deep within the brain centers that were known to respond to rewards, there was a lot of activity. Subjects were also found that they were more likely to eat unhealthy foods after a night of very little sleep.


SEE ALSO: 12 Dangers of Sleep Deprivation Infographic


In another study, rats were forced to walk on a treadmill during hours that they were used to sleeping, similar to the way people who worked overtime or worked the night shift. Then the sleep deprived rats were compared to another group of animals that were denied food and another that also ran on a treadmill, but during normal waking hours.

Researchers compared the brain scans of all three groups. The rats deprived of sleep showed an increase in activity of the gene that makes an opioid peptide called PENK (proenkephalin). PENK is normally found in the brain and it can activate the exact same receptors that heroin or morphine can.

Rats that did normal treadmill activity had normal levels of the PENK gene, even if they were kept on a reduced diet. These enhanced amounts of the PENK opioid decreased quickly almost immediately after eating, telling the brain to stop eating after it has met its nutritional needs.


It was found, however, that the rats that were sleep deprived, their PENK gene was stuck in the ON position. Besides the PENK gene, the rats that did not sleep much showed high levels of prodynorphin, a chemical that is found in humans who are going through withdrawal from drugs.

If you hope to lose weight, it’s fairly obvious that you need to get enough sleep every single night. This can reduce cravings and help you to make, and want healthier food choices during the day.