This workshop will focus on how the principles of lifestyle medicine can be used to prevent the development of obesity at key life stages throughout the lifespan. These stages include childhood, early adulthood, middle adulthood, and older adulthood. Case studies will be used to demonstrate the different etiologies and reasons for weight gain in these age groups and the implications of this weight gain on long-term health. These case studies will use military and veteran healthcare patients since the Department of Defense and Veterans Affairs healthcare organizations often provide a continuum of care across patients' lifespans. The six pillars of lifestyle medicine will be explored as interventions to prevent weight gain across the lifespan. Practical skills for the prevention of the development of obesity in individuals and populations will be taught using a multidisciplinary approach.