The present paper introduces interpretative phenomenological analysis (IPA) as a framework for analysing qualitative research data collected for public health nutrition and dietetic research studies. The theoretical roots of IPA have been set out briefly in order to help researchers decide whether the approach is relevant for them and their particular research questions. IPA can be used to analyse data from one-to-one interviews in order to develop 'thick descriptions' that may help illuminate human experience. IPA can also be used to develop theories and/or models, which could help inform policy. The main body of the paper describes the analytical techniques and procedures used to achieve both outcomes in a practical way, using examples from the author's own research. In the following paper Krueger's methods for analysing focus group data are set out for comparison. It is hoped that these papers will empower researchers with little experience of qualitative research to develop confidence with qualitative data analysis. In addition, it is hoped that the material will stimulate debate amongst more experienced qualitative researchers from a public health or dietetic background.