A food or eating addiction is any behavioral addiction that is primarily characterized by the compulsive consumption of palatable (e.g., high fat and high sugar) food items which markedly activate the reward system in humans and other animals despite adverse consequences.

Psychological dependence has also been observed with the occurrence of withdrawal symptoms when consumption of these foods stops by replacement with foods low in sugar and fat. Because this addictive behavior is not biological, one cannot develop a trait that codes for an eating disorder, so professionals address this by providing behavior therapy and by asking a series of questions called the YFAS (Yale Food Addiction Scale) questionnaire, a diagnostic criteria of substance dependence.

Sugary and high-fat food have both been shown to increase the expression of ΔFosB, an addiction biomarker, in the D1-type medium spiny neurons of the nucleus accumbens; however, there is very little research on the synaptic plasticity from compulsive food consumption, a phenomenon which is known to be caused by ΔFosB overexpression.