In American culture, it's bad to be fat. Rarely is this more apparent than at the start of the new year, when diet culture, fat phobia and capitalism converge. Exploiting body shame and people's desire for renewal, weight loss companies ramp up ads, gyms reduce rates and diet companies promise to help people realize the elusive goal of weight loss that lasts.Sociologists and medical professionals who treat patients using a model of health at every size say this yearly cycle underscores society's obsession with thinness and fuels dangerous misperceptions about the relationship between weight and health."I tell patients right off...