Changing how you eat and adapting to healthy lifestyle behaviors can be good. However, extreme dieting is an unhealthy way to lose weight and although many individuals who go on strict diets indeed develop an eating disorder, eating disorders have deep underlying causes associated with them that are more than just about food. Many individuals with eating disorders have issues with self-control and body image and use their obsession with food to cope with their underlying issues. Strict diets, in general, are deemed unhealthy because they have unrealistic expectations and goals.