This work is a printed edition of the two-hour lecture on the pathophysiology of obesity that Dr. Donovan gives to his weight loss patients. This book covers topics such as why we gain weight, why we should lose excess fat and how to keep it off. The reader will understand that obesity is a chronic disease and can be treated by using food as a drug to cause better weight loss. Dr. Donovan discusses the laboratory tests he does for his obese patients and explains the science in a language easy to understand. A good resource for people who want to lose weight and for physicians who want to help them.