Introduction: The metabolism of fatty acids in plasma is modulated by their availability in plasma. Individuals with increased weight have increased plasma fatty acids and physical exercise seems to favor the metabolic responses of fatty acid mobilization. Objective: To test the hypothesis that the physical exercise of acute way changes the fatty acids of medium chain of the serum of individuals with increase of the corporal weight. Method: Including 66 women, randomly divided into two groups, control and experiment, overweight, sedentary, and between 18 and 30 years of age. After a 12-hour fast, basal blood collection will be performed. The experiment group, 12 hours after the first collection, will be submitted to a physical exercise session with energy expenditure of 250Kcal. The volunteers in the control and experiment group will make a second blood collection 24 hours after the first one. The fatty acids will be dosed: pelargonic, azelaic, elaidic and oleic by gas chromatography. Intra and intergroup comparisons will be made using the t test for independent and dependent samples, p <0.05.