While Americans claim to be eating better and improving their understanding of diet and health, they are getting heavier and increasing their risk of suffering from diet related illnesses. The cause of this inconsistency is unclear. Using theoretical models of preference reversal and econometric empirical analysis, this study finds that the number of calories eaten per meal increases and the quality of the diet decreases as people wait more than six hours to eat their next meal, work more than fifty hours a week, and consume a larger amount of food away from home. These situational factors are important even for consumers who have considerable knowledge about diet and health. Regardless of one's favored dietary prescription, this study shows how well an individual's intentions to eat healthfully changes with time pressures, hunger, and food source. As people change their dietary goals based on prevailing nutritional lore, such situational factors will continue to interfere with one's long-term health objectives. This is especially relevant in an era where obesity is a leading health issue for individuals and for the costs of health care. Any advice and action that can improve diet quality and reduce caloric intake on a convenient basis is valuable for individuals and the overall economy.