Depakote (Abbott Laboratories, Abbott Park, IL) is an anti-convulsant medication used to treat epilepsy [1] and mania associated with bipolar disorder [2, 3]. Depakote also is used as a prophylaxis for migraine headache [4]. One side effect of Depakote that negatively influences its appeal to health care professionals and consumers is weight gain. It is unknown if changes in energy intake, energy expenditure, or a combination of both are responsible for this side effect. The purpose of the proposed study is to: 1) test if Depakote increases body weight by increasing food intake or decreasing energy expenditure, possibly through changes in posture allocation, and 2) identify methods to prevent and treat weight gain in people taking Depakote. This randomized placebo-controlled trial will measure both sides of the energy balance equation (energy intake and expenditure), and posture allocation (the time spent in active and sedentary behaviors, and the energy cost of these behaviors). Measurement of both total daily energy expenditure (TEE) and posture allocation provides a powerful tool to determine if Depakote decreases energy expenditure by increasing the time spent in sedentary behavior. These data, along with the food intake data, provide a test of the mechanisms responsible for weight gain associated with Depakote, and these data can identify methods to prevent or treat this weight gain.