Understanding dieting in young people: examining the characteristics, intentions and eating disorder risk of a cohort of young people aged 16-25 years

Abstract

Dieting is a 160 billion-dollar industry, which has grown rapidly over the past 50 years. Over 2.3 million Australians are believed to be on a diet at any one point in time, with rates of dieting, likely higher among older adolescents and young adults (i.e., young people), for whom, weight loss dieting is a normative behaviour. Dieting is often done without the support of a professional (i.e., self-directed and unsupervised), leading to negative psychosocial outcomes (e.g., heightened eating disorder risk, disordered eating, weight gain), especially among young people. This thesis sought to better understand the dieting experiences, characteristics and eating disorder risk of young people going on a self-directed, unsupervised diet in the community. To begin, a thorough literature review outlining the different types of diets, dieting behaviours and goals of dieting, as well as the history of dieting, the inherent difficulty of dieting and associated psychosocial outcomes, was conducted (Chapter 2). To address identified research gaps from this review, we design an observational, naturalistic, longitudinal study of the process of dieting in young people (Chapter 3). In Chapter 4, we screen over 700 young people planning to start a diet in the community for initial eating disorder risk and find that nearly 40% of those signing up to our study on dieting are at already at-risk of an eating disorder, according to a well-validated measure. In Chapter 5, we report in detail on the prospective diet plans and sociodemographic and psychological characteristics of a cohort of nearly 500 young people. Finally, in Chapter 6, we report on how eating disorder risk may unfold in a cohort of young people starting a self-directed, unsupervised diet in the community. The findings of this thesis are discussed in terms of their implications for public policy, prevention and early intervention efforts, and future research.