 Obesity is an important risk factor for osteoporosis and fractures. With the growing prevalence of obesity in the U.S., understanding the pathophysiology of bone loss in this population is of importance to public health. Growth hormone GH is a critical mediator of bone homeostasis and is markedly reduced in obesity. Our preliminary data suggest an important role for the GHinsulin-like growth factor 1 IGF-1 system in the pathogenesis of bone loss in obesity. The development of novel imaging techniques provides an opportunity to investigate the effects of GH on skeletal structure and strength, which will provide insights into the pathogenesis of obesity related bone loss. Understanding the pathophysiology of bone loss in obesity may help identify new treatment targets for this important complication. The investigator hypothesizes that low-dose GH administration for 18 months will improve skeletal health. 