In this article, we examine the social management of fatness via an analysis of 4 years of participant‐observation in military‐style fitness boot camps and interviews with camp participants, trainers and organisers/owners. We begin by focusing on popular imagery of the ‘boot camp’. The boot camp model takes various forms; yet, whether it involves civilian participants, as on reality television shows, or the imagined military ones of films, the boot camp model emphasises the re‐fashioning of the individual via the disciplining of bodies and selves. Such constructions of boot camps were employed by our respondents to lay claim to identities which highlight their hard work, strength of character, fundamental ‘goodness’ and self‐discipline, as those qualities are demonstrated through the body – even though participants’ actual bodies change little at camp. Such meanings stand in direct contradiction to broader social constructions of fatness and participants’ own negative perceptions of fat people. Moreover, even within the camps themselves, such identity claims are contested, both by camp trainers and by slimmer and ‘fitter’ attendees. These counterclaims are grounded in ideas about the characterological implications of the fat body, beliefs about the purpose of boot camp and notions of the body's capacity for change.