Overeating occurs when an individual consumes more calories in relation to the energy that is expended via physical activity or expelled via excretion, leading to weight gain and often obesity. Overeating is the defining characteristic of binge eating disorder.

This term may also be used to refer to specific episodes of over-consumption. For example, many people overeat during festivals or while on holiday.

Overeating can be a symptom of binge eating disorder or bulimia nervosa.

Compulsive overeaters depend on food to comfort themselves when they are stressed, suffering bouts of depression, and have feelings of helplessness.

In a broader sense, hyperalimentation includes excessive food administration through other means than eating, e.g. through parenteral nutrition.