Abstract: A passive nutrition tracking service automatically tracks food consumption over time for a user and for populations from a variety of food consumption sources, including food purchase input such as grocery loyalty shopping card data, restaurant dining data, estimates of food consumption within a household, estimates of free food intake and estimates of food pantry use. The tracking service also passively tracks and uses total energy expenditure information for the user, which describes the physical activity level, muscle and fat gain, and optionally waste output of the user. The tracking service analyzes the food consumption and user energy expenditure information and generates a food dietary history for the user, which includes calories and nutrient consumption estimated based on the analysis. The tracking service also generates a variety of personalized healthy lifestyle recommendations based on the analysis and presents the dietary history and personalized healthy lifestyle recommendations to the user.