Conventionally, fruits and vegetables have been the major source of micronutrients. However, with the rising availability of nutritional supplements, U.S. consumers no longer need to rely on food alone for their nutritional needs. Time-pressured consumers with limited cooking skills and nutrition knowledge may find it easier to take vitamin supplements. The objective of this paper is to determine the impact of lifestyle, diet behavior including vitamin supplement consumption, and food culture on diet quality outcomes as measured by the Healthy Eating Index-2005 (HEI) and total energy intake. We use the 2003-04 U.S. National Health and Nutrition Examination Survey (NHANES) to examine the relationship between HEI and caloric intake. Further, our specific focus is to determine the role of vitamin supplements in the U.S. diet by developing a profile of supplement consumers. In addition, we consider the caloric implications of diets that substitute vitamin supplements for fruits and vegetables. Selected variables include demographic and socioeconomic factors, as well as a large number of dietary, health indicators, and lifestyle-related information. Findings from our econometric model show that consumers of vitamin supplements display higher HEI scores and consume diets with more calories. Specifically, our empirical results find that dietary supplements are consumed by female, married, college-educated senior respondents. Individuals who might believe they need to eat better also consume vitamin supplements. These are respondents who have been told by a health professional that they have high blood pressure and elevated cholesterol levels. Thus, vitamin supplement consumption seems to be another marker for healthy eating. It also raises concerns since healthy eaters do not need the supplements, and may consume some vitamins and minerals above the upper level.