Carbohydrate craving, mood changes, and obesity.

Carbohydrate craving can cause weight gain in affected people and is present in women with premenstrual syndrome (PMS) and persons with seasonal affective disorder (SAD). The neurotransmitter serotonin regulates carbohydrate intake; its precursor, tryptophan, enhances serotonin release. Animal studies have shown that serotonergic drugs decrease carbohydrate consumption. Three studies of the eating patterns of over 150 obese subjects have shown that carbohydrate craving occurred at specific times, that is, at 4 p.m. and 9 p.m. A serotonergic drug (D-fenfluramine) has been shown to decrease carbohydrate consumption by 40%. Further dietary and pharmacological studies of PMS and SAD are needed to determine serotonin's involvement with symptoms of depressed mood, increased fatigue, and carbohydrate craving.