Examination of the health-belief model to predict the dietary quality and body mass of adults

We examined the ability of the health-belief model to predict individuals' dietary quality and body mass among a nationwide sample of 1319 adults in the United States. Simultaneous estimation of the structural equation model found acceptable goodness-of-fit to the data. Explained variance in dietary quality and body mass, however, were moderate to weak. The model included three types of nutrition knowledge: basic facts, diet-health awareness and ability to accurately self-assess nutrient intake. None of these variables had a strong effect on dietary quality or body mass. We speculate that lifestyle characteristics, cultural habits, community infrastructure, and the politics of food production and retailing - variables found in other studies to affect dietary quality and body mass yet not available in our data - might outweigh the effects of nutrition knowledge and sociodemographic factors on estimating dietary quality and body mass. We suggest that future research and intervention programmes focus more on social, cultural and political context than on nutrition knowledge. Current collaborations among life and social scientists to design foods to improve human nutrition might also prove effective in reducing the prevalence of overweight and obesity.