Microarray gene expression profiling of skeletal muscle tissues collected from obese and morbidly obese patients. Skeletal muscle biopsies were obtained during abdominal surgery performed on obese, morbidly obese and lean women (n=8 per group), after a 12-hour, overnight fast. Morbidly obese patients had a body mass index (BMI) exceeding 40 kg/m2 and lean subjects had a BMI < 25 kg/m2. All subjects were nondiabetic and were not taking any medications known to affect carbohydrate or lipid metabolism.