Reducing the current level of meat consumption would reap significant environmental benefits. However, a consumer transition towards more plant-rich eating is lagging, and the social sciences have had limited success in understanding behavioural change in this area. Here, we advocate a research agenda focussing on the role social networks could play in encouraging consumers to eat less meat. We present main research directions in social network theory and highlight the distinction between simple and complex behavioural domains of which food and eating practices are an example of the latter. To illustrate one way in which social network insights can contribute to meat reduction research, we then present results from a questionnaire-based study of Danish consumers. We examine the association between an individual's personal network and reduced meat consumption. In line with assumptions, we show that, for a complex domain such as food and eating practices, exposure from multiple network sources is central to behavioural adoption. However, multiple network exposure is predominantly important for the initial decision to eat less meat. A narrower network of personal contacts become more central during the implementation stage. We end by outlining future research directions for social network research regarding meat reduction.