NPY is a neurotransmitter than your brain releases when it’s hungry. This signal triggers cravings for carbohydrates, and is highest in the morning.  NPY is a natural response that is released in response to a time of food deprivation. For intuitive eaters, and people who aren’t restricting themselves, their NPY levels go down once they eat. But if you deprive yourself of food for a long duration, which is commonly seen in disordered eating and dieting, this can cause chronically elevated NPY. This causes you to still get intense cravings for food even after you’ve eaten.  If you’ve tried to restrict you calories in the past and got bad cravings for carbohydrates that may have led to binging, chronically high NPY may have contributed to this.