Debunking the High Cost of Healthy Diets: Consumer Behavior Predicts Dietary Energy Density in a Nationally Representative Sample of US Adults

Purpose: Dietary energy density (ED; kcal/g) is an established marker for diet quality and a risk factor for obesity. Previous studies have suggested that low-ED diets cost more than high-ED diets, adding an economic contribution to the obesity epidemic. This study evaluated the relationship between consumer behavior (money spent on food) and dietary energy density in a nationally representative sample of US adults. Design, Setting and Subjects: Data from 10,622 adult participants in the 2013-2016 NHANES were used for this study. The NHANES is a large cross-sectional survey conducted by the CDC and NCHS. Measures: Consumer behavior was evaluated by examining total dollars spent on food, as well as dollars spent at various categories of food stores & restaurants. Dietary ED was calculated using multiple methods. Analysis: Multivariate regression models were then used to evaluate the relationship between consumer behavior, defined as money spent in four categories (groceries, take-out, dining out, other food purchases) and dietary energy density. Results: Low-ED diets did not cost more than high-ED diets overall, though low-ED diets contained more servings of fruits (1.6 vs 0.4), vegetables (2.2 vs 0.9) and fiber (21 vs 13g), and fewer added sugars (15 vs. 18 tsp), solid fats (28 vs 39g), all p’s \u3c 0.01. Differences in spending patterns were identified. A positive linear trend between money spent on fast food/takeout and dietary energy density (p \u3c 0.001) was observed. Additionally, individuals in the lowest quartile of ED spent more at grocery stores per person than individuals in the highest quartile of ED ($182 vs. $150 p = 0.04). Conclusion: Spending pattern and consumer choices are associated with dietary ED in this cross-sectional analysis of a nationally representative population sample. Identifying eating behaviors associated with diets high in energy density may inform future investigations that intervene on dietary habit for promotion of healthy eating and prevention of weight gain