The recruited sample will include both males and females between the ages of 25-55 years with BMIs between 25-40. This age range reflects the modal ages for obese participants presenting for behavioral weight loss, and individuals with BMIs greater than 40 typically do not fit comfortably within the scanner bore. As with previous studies at the WCDRC, all participants will be weight stable (defined as within +/- 5 lbs. for the past two months).