Antioxidant-restricted diet reduces plasma nonesterified fatty acids in trained athletes.

Nonesterified FA (NEFA) are a major fuel source for humans at rest and during moderate exercise. The effect of dietary antioxidant restriction on plasma NEFA levels and exercise performance in trained athletes was examined. Seventeen athletes followed a 2-wk restricted-antioxidant (R-AO) diet, which resulted in a threefold reduction in antioxidant intake (ascorbic acid, 139 to 49 mg; beta-carotene, 5093 to 1142 microg) and a significant (P = 0.001) reduction in the plasma NEFA. The amount and types of fat consumed were not different between the R-AO and habitual diets. Exercise time to exhaustion was not affected by the R-AO diet, but rating of perceived exertion (RPE) was significantly (P = 0.03) elevated. The increase in RPE may have occurred as a result of the R-AO diet and subsequent reduction in plasma NEFA; however, further research is required to confirm this conclusion.