This book provides up-to-date evidence-based information on why and how to implement exercise intervention in the treatment of obesity. It starts with a description of the epidemiology of obesity, how to execute preparticipation screening in the obese, and the impact of caloric intake restriction vs exercise training in obese subjects. Next, a detailed description of exercise physiology in obesity is provided, followed by motivation techniques, the impact of training modalities on adipose tissue mass loss, and an exploration of factors related to the heterogeneity of adipose tissue mass loss in the obese when following exercise interventions.