This application is in response to PAR-12-048, "Prevention and Treatment of Obesity, Diabetes, and Chronic Kidney Disease in Military Populations". Active U.S. military personnel have mirrored the marked civilian increased prevalence in obesity. A survey conducted in 2005 reported that 61% of men and 39% of women serving in the active component of the U.S. military had a body mass index that classified them as overweight (Body Mass Index [BMI] >25 kg/m2) and 12% of active service members were obese (BMI>30 kg/m2), up from less than 5% in 1995. Given that the national epidemic of obesity continues, one would expect those prevalence rates to be even higher today. While the Announcement highlights the advantages of conducting research in military populations, there are also many logistical, practical, chain-of-command, philosophical, and other challenges that impede health promotion and other research in the military. Fortunately, our research team has a long history of conducting health promotion/disease prevention in the military and has a military liaison (Wayne Talcott, Ph.D., Col, USAF [retired]) who helps ensure the effective day to day running of our multiple projects. The key to successful research in the military is to address significant health promotion issues (e.g., smoking, alcohol abuse, obesity) that are (a) costly to the military;and (b) most importantly, impediments to military readiness (which is the ability to do one's job in either combat or non-combat situations). Given that obesity is an impediment to military readiness (a vital concern for the military), the need for obesity interventions in this high risk population and the dearth of research on obesity treatments in the U.S. Military, we propose the following specific aims: 1) To translate and tailo the Look Ahead weight loss intervention to the overweight/obese active duty U.S. Military population, while accommodating the lifestyle and environment that is unique to military members; (2) To randomize 520 participants to either the Look Ahead Intensive Lifestyle Intervention (ILI) versus a Diet and Physical Activity Education (Diet/PA Ed) condition. The Diet/PA Ed condition of this Look Ahead translation is not a placebo control group but an active information group that stresses nutrition, exercise and support (similar to the Diet Support and Education control group in the original Look AHEAD trial). (3) To evaluate the long term (one year) efficacy of the Look Ahead weight loss intervention in this population. The results of the intervention if successful will be easily disseminated to the entire U.S. Military as this project s designed to overcome the barriers and exploit the facilitators for weight loss that are unique to a military population. It will also better inform translation of the Look Ahead Rx in civilian populations as well.