The influence of consumption practice‐based communities on consumption patterns is a growing trend in marketing research. Vegetarianism, a diet that usually represents a break away from eating patterns strongly anchored in society, generates psychological and relational tensions for those who adopt it. As such, vegetarians develop specific links with the adoptive vegetarian community, which may strongly influence the adoption and maintenance of this practice. The purpose of this research is to better understand how vegetarians' relationships with their social environment and community impact their consumption behaviours. An exploratory study was carried out based on 23 individual interviews with young adult vegetarians in France. The results shed light on the self‐categorization process and show how relationships with the community influence the adoption and maintenance of vegetarian behaviour. In addition, depending on the perceived opposition between society and the vegetarian community and the degree of identification with this community, different patterns of relationships with and expectations of the community are identified and presented in the CBO model (Community Belonging and perceived Opposition between community and society). Understanding the social influences involved in practice‐based adoptive communities will help marketers take decisions relating to support, supply and communication with regard to these practices. Beyond describing the practices and motivations underpinning vegetarianism and veganism, previously documented in the literature, this research provides new insights into the impact of communities and social influences on the adoption and defence of a specific diet.