BACKGROUND AND OBJECTIVES: Financial limitations in low-income populations, those at highest risk for poor health outcomes, may preclude adherence to recommended dietary guidelines. We examine the financial burden of shopping for foods to meet national dietary recommendations in a supermarket compared to eating primarily in a fast-food restaurant. METHODS: Using a single-parent, low-income model, we obtained whole food costs (healthy) from local supermarkets and from fast-food outlets (convenient). Using cost per calorie as a metric for comparison, we used estimated single-parent, low-income living expenses to determine the relative costs of meeting national dietary guidelines. RESULTS: Average food costs for healthy and convenience diets accounted for 18% and 37% of income, respectively. Dairy products and vegetables accounted for the largest cost percentages of diet costs (36% and 28%, respectively). The cost per calorie of a convenience diet was 24% higher than the healthy diet. Both models resulted in net financial loss over the course of a year for a single-parent, low-income family. CONCLUSIONS: Food costs represent a significant proportion of annual income. Diets based heavily on foods from convenient sources are less healthy and more expensive than a well-planned menu from budget foods available from large supermarket chains.