Background: Gradual elevation of body weight leads numerous individuals to dieting and weight loss behaviours. Nevertheless, the prevalence of obesity continues to rise in industrialised countries. The examination of the motivational determinants of dietary modification ("dieting") in order to identify clusters of individuals in the first 6 months of their effort to control body weight was the aim of the current study. The theories of self-determination and self-esteem formation guided our analysis. Methods: A longitudinal study was conducted with three data collection points (N1=256; N2=135; N3=75). Data were responses on the Treatment Self Regulation Questionnaire, Social Physique Anxiety Scale, Physical Self-Description Questionnaire, Kaiser Physical Activity Survey Questionnaire, and items assessing expectations of achievement and self-confidence. Results: Cluster analyses provided stable and validated cluster profiles for all data sets. In the 1st and 2nd data sets, results revealed three groups of dieters labelled as "media victims", "try to feel nice" and "older and experienced". For the 3rd data set, results supported a 4-group solution ("less adaptive profile", "second successful dieters", "successful dieters", and "unsuccessful dieters"). The need for autonomous versus controlling dieting reasons based on Self-Determination Theory, along with the need for an alternative paradigm in weight management, are proposed. Conclusions: Psychological theories of self-determination and self-esteem provide important ways of understanding and identifying adaptive and less adaptive weight control strategies. (Contains 2 tables and 7 figures.)