Prevalence and Demographics
ANDREW J. HILL
In the developed world, the malnutrition of poverty has given way to the malnutrition of affluence. Externally imposed food shortage has been superseded by self-imposed food restriction. For some sections of society, dieting and body dissatisfaction appear to have become normal, even normative. This chapter considers what is meant by dieting, summarizes the research on its prevalence, identifies who is most likely to engage in dieting, and looks to the future.
Research interest in the prevalence and reasons for dieting started in the mid-1960s. This interest has increased with a flurry of surveys published during the last decade. However, comparability across studies is problematic. Prevalence estimates vary widely according to what is asked. General questions (e.g., Are you trying to lose weight?) produce higher levels of endorsement than more specific ones (Are you currently dieting to lose weight?). Epidemiological surveys of large, representative samples tend to use a limited number of general questions, since the assessment of dieting is often a subsidiary part of the overall study. In contrast, studies with smaller samples may be designed for the purpose of detailing dieting but they tend to be directed at high-risk groups.
Dieting is not uniform in its implementation. For some dieters, it signifies a simple desire to lose weight. For others it refers to the periodic use of several weight-loss behaviors. For still others, dieting represents attempts to maintain their current weight and prevent weight gain. These differences in purpose are mirrored by differences in the composition, intensity, and duration of weight-loss diets. There are also serious questions about the validity of self-reports of dieting, since memory biases, social desirability, and the brittle nature of dieting make uncertain the degree to which simple affirmations reflect consistent changes in nutritional behavior.