Dieting can quickly tip over into an eating disorder - anorexia or bulimia. Young women in particular are affected. But with social media, the number of people affected has increased dramatically once again. SIZE ZERO - the female clothing size zero (32 or XXS) - has become synonymous with diet and fitness programs with an online platform for sharing before-and-after selfies. The physician Dagmar Pauli, renowned expert for the eating disorders of young people, gets to the bottom of these connections for the first time, names causes and responsible persons and shows ways out of the eating disorder trap. "Size Zero" addresses those affected and those at risk: young people who have self-doubt and long for affirmation. Their brains have been plastered with images of super-thin stars and models from an early age. Young people who live in a world of "good and bad".