When energy is in excess, the human body processes nutrients according to an oxidative hierarchy. Excessive carbohydrate and protein intakes are disposed of by increased oxidation. In contrast, excess fat intake does not promote its own oxidation in the short- and mid-term. This leads, in the long-term, to an increase in fat stores. Although increased adiposity represents the common response to increased fat intake, there are interindividual differences in lipid oxidation (probably genetically determined) that may protect from or predispose to obesity. J Am Diet Assoc. 1997; 97(suppl):S42-S46.