Food‐related behaviours are complicated actions governed by a mix of cultural conventions, social interactions, individual perceptions and psychological influences. The methods introduced here should support nutrition studies by providing tools to measure the reasons behind food choices and intake more effectively. This chapter covers the general principles in applying the specific methodologies and demonstrates what information different methods can give us about the factors influencing behaviour. Quantitative strategies for investigating food‐related behaviours include experimental and survey research. Survey research designs allow for the quantitative or numerical description of variables and enable the researcher to make claims about a population. Mixed‐methods research combines both qualitative and quantitative forms in its assumptions and approach. A mechanistic approach helps explain why some of the traditional forms of intervention such as providing information may not have been successful in changing food‐related behaviour.