doctor jason nagata is a pediatrician specializing in eating disorders at the university of california, san francisco. he's also editor of the book "eating disorders in boys and men." doctor nagata, do eating disorders look different in boys than in girls? >> yes, absolutely. the masculine body ideal is big and muscular, and this can lead to muscle building behavior like excessive exercise, restriction of carbs and fat, while overconsuming protein, and use of muscle building supplements and drugs like anabolic steroids. when taken to the extreme, this can lead to muscle dysmorphia, also known as reverse anorexia or biggerexia. and this is why somebody pathologically becomes obsessed with the idea that their body is too puny or scrawny. and they need to become more muscular. john: what does over exercise, too much protein, not enough carbohydrates, what does that do to the body? >> in simple terms, we need to maintain, you know, an energy balance. so whatever energy we're exerting through physical activity or exercise, we need to take in and out for nutrition. i think it's pretty well r