This report comprises three interrelated studies undertaken to investigate the age at onset of the disturbances in body image reported by some obese persons. A group of 20 preadolescent girls, although subjected to derogation of their obesity by peers and parents, did not manifest the kind of body image disturbance reported by adults. Three of a group of ten obese children who reduced to normal weight during adolescence and maintained their weight loss reported the persistence of mild body image disturbance 20 years later. These findings, in conjunction with previous reports of onset of the disturbance during adolescence, suggest that adolescence is a critical period for the development of this disorder.Additional findings of two of these investigations contribute to our understanding of the natural history of obesity. Two kinds of weight histories are surprisingly uncommon: 1) of 189 obese adults, only two had been both obese as children and nonobese as adolescents; 2) only 17 percent of a group of obese children were normal-weight adults. In this group the odds against an obese child being a normal-weight adults. In this group the odds one; for those who did not reduce during adolescence they were more than 28 to one.Abstract Teaser