An overactive gland can make you stay awake when you shouldn’t be by making you anxious and increasing your pulse. The condition overstimulates the nervous system, making it hard to fall asleep. Lack of sleep can lead to weight gain. Sleep deprivation affects the brain in a way that makes you want to eat more and not process food efficiently. Science says getting less sleep than needed makes the body produce higher peaks of endocannabinoid, a lipid in the bloodstream that’s responsible for making eating feel more enjoyable; hence, you always want to eat. Also, if you’re on little sleep, fat cells’ ability to react properly to insulin (the hormone that regulates energy storage) decreases by 30 percent.