For the last few years, the nutritional quality of food has again become a concern to public health policies. Policy makers would like to find the best ways to act on the food choices of the population. This document shows how economists analyse nutritional taxation and information policies. Taking obesity as an example, it is shown that the main source of ineffectiveness of non-targeted policies (taxation or general information campaigns) is the presence of individual heterogeneity, unobservable or observable. Information policies targeted at high-risk populations, or taxes or subsidies to products provided by institutional catering could be more effective.