Few studies have been performed to use the detailed healthy eating index (HEI) to estimate consumer demand for diet quality. In this article, we apply household production theory to systematically estimate consumer demand for diet quality using the HEI developed by the U.S. Department of Agriculture. The results show that consumers have insufficient consumption of food containing dark green and orange vegetables, legumes and whole grains. Age and education have a significant impact on consumer demand for diet quality, but income does not. The own-price elasticities of demand for diet quality are inelastic. Simulation of tax scenarios indicates that a tax on sugar-sweetened beverage may be more efficient than a tax on fats, oils and salad dressing in improving consumer diet quality. This information is critical for policies and programs that are designed to improve healthy food choices, thereby reducing the social cost of public health.