Eating habits are influenced by emotional factors. Persuasion to change wrong habits should therefore act on the central and the peripheral route at the same time, by combining rational and emotional strategies appropriately. In this paper, we describe an ongoing research which is aimed at simulating persuasion dialogs in this domain. We describe how we collected and analyzed a corpus of messages and how we compared the persuasion strength of rational vs emotional, negatively vs positively framed discourses. We conclude the paper with a discussion of the knowledge representation methods that are suited to represent these strategies.