All obesity is mute testimonial to over-eating.
Excess fat accumulation is an artifact of disordered eating behaviors with food energy intake exceeding energy expenditure. The extra food may be ingested slowly and gradually, although most people gain weight in spurts, as a consequence of binge-eating or periodic indulgences in extra foods, alcoholic beverages, desserts, and snacks. Rapid weight gain may be associated with hormonal changes, as in pregnancy or low thyroid states, or whenever life-style changes, injury, or illness reduce physical activity. Without a balanced reduction in food intake or change in food selection, reduced physical activity produces weight gain. Bursts of weight gain represent maladaptive responses to a variety of stressors.