When the level of serotonin in your brain falls, your body senses starvation, and to protect itself, starts craving carbs. Serotonin levels plummet after you go to long without eating, and that prompts your bodily machine to fill itself with foods. Some people have tried to keep their serotonin level up by supplementation with 5-HTP, the breakdown product of tryptophan that converts to and stimulates serotonin. In a six week study, a group of dieters using 5-HTP lost an average of twelve pounds, while a control group lost an average of four. Although one side effect of the supplement is nausea, about 90 percent of women taking 300 miligrams of 5-HTP reported satiety while on the diet.
