The Impact of Nutritional Supplement Choices on Diet Behavior and Obesity Outcomes

Despite decades-old efforts to inform and educate consumers about healthier lifestyles through established dietary guidelines, diet-related diseases are on the rise. At the same time, consumers have developed more favorable attitudes towards nutritional supplements as a perceived alternative way to improve diet quality. Thus, there is a need to understand the role of nutritional supplements in U.S. consumers’ diets, given that supplements might serve as a possible policy tool to improve dietary behavior. We use data from the National Health and Nutrition Examination Survey (NHANES) to estimate the impact of nutritional supplements intake on respondent’s body weight outcomes, while controlling for diet quality based on individual Healthy Eating Index (HEI-2010) scores. Our analysis applies a set of innovative Propensity Score Matching (PSM) estimators that account for potential selection bias and endogeneity of the self-reported behavior and diet-health outcomes. The empirical analysis demonstrates a negative association between nutritional supplement intake and BMI. Our findings suggest that health-conscious individuals overinvest in health by taking nutritional supplements instead of improving diet quality through more appropriate food choices. Nutritional supplements have been discussed as a disease-preventative input that may enhance the 2 diets and health of at-risk populations. The analysis in this paper suggests that consuming supplements should not be thought of as a replacement for a healthy food-based diet. Our study provides an important contribution to the literature on a key food policy issue and contributes new insight with regard to the relationship between dietary choices and health behavior