In this project, we propose to recruit lean and obese subjects with different ethnic background (African Americans and Caucasians) to study the alterations of lipid and carbohydrate metabolism and determine whether these disturbances are linked to genetic, inflammatory, oxidative stress, and/or nutritional factors. Because systemic inflammation and insulin resistance are frequent features of obesity, we postulate that an unbalanced diet with high saturated- and low omega 3-fatty acids is linked to obesity-related inflammation and insulin resistance. We propose to investigate fatty acid metabolism and determine the links between fatty acid composition and oxidative stress in tissues of lean and obese subjects. We propose the following aims: