Dennis Mangan is a microbiologist who teaches men how to clean up their diet and get strong with science-based health and fitness. For decades he followed a vegetarian diet, watched his cholesterol intake, and engaged in long distance running for physical fitness. Yet, he got sick and suffered from chronic fatigue. Now, he engages in strength training, eats food that is as minimally processed as possible and returned to eating meat. At the age of 63, Dennis looks and feels better than ever.