Total energy intake acts as a primary determinant of disease risk and serves as a critical confounder in nutritional epidemiology because nutrient intakes are positively correlated with total energy consumption.

Total energy intake deserves special consideration in nutritional epidemiology for three reasons: firstly, the level of energy intake may be a primary determinant of disease; secondly, individual differences in total energy intake produce variation in intake of specific nutrients unrelated to dietary composition because the consumption of most nutrients is positively correlated with total energy intake; and, thirdly, when energy intake is associated with risk of disease but is not a direct cause, associations with specific nutrients may be distorted (confounded) by total energy intake.