This article addresses the extent to which increases in energy intake as opposed to decreases in energy expenditure are driving the obesity epidemic. It argues that while both intake and expenditure are plausible and probable contributors, the fact that all intake is behavioral, whereas less than half of expenditure is behavioral, makes intake a conceptually more appealing primary cause. A review of per capita food disappearance trends over time and of trends in individual intakes is presented to support the plausibility of this perspective. Increases in energy intake mirror increases in body weight quantitatively and are equally widely distributed across diverse groups within the larger population.