Cravings for carbohydrates (mostly high sugar choices)may be caused by low serotonin levels. Carbohydrates help ensure the body has sufficient tryptophan to allow the brain to produce desirable serotonin levels. Serotonin is a hormone essential for relaxation and sleep.
Kalsy, Leandra J. (2012-11-15). 10 Simple Steps To YoYo Dieting Freedom: How To Begin Freeing Yourself from Diets and Enjoying Food Again (Kindle Locations 136-138). Kindle Edition.