The aim of this work is to contribute to the study of the effect of organic depression in lipid metabolism of livestock during seasonal tropical areas drought conditions. As a model, rats were used in the study. Sixteen Whister male rats were divided in 2 groups: C (control) fed ad libitum and R (restricted feeding) fed 34% energy maintenance needs, simulating livestock weight loss in frequent drought seasons. Animals were slaughtered at day 23 of the experimental period and samples were taken from plasma and gastrocnemius muscle. Undernutrition significally induced the increase of % free C14:0 content in the plasma and decreased the % C16:0 incorporated in triacylglycerols of muscle fat. In underfed rats, C18:0 suffered a relative increase in its free and in its sterified form in the adipocytes of the muscle. Food restriction decreased the % of C18:1 as free fatty acid in the muscle and in plasma. These results are consistent with the existence of a preferential degradation of long-chain fatty acids in underfed rats.