An abundance of data unequivocally shows that exercise can be an effective tool in the fight against obesity and its associated co-morbidities. Indeed, physical activity can be more effective than widely-used pharmaceutical interventions. Whilst metformin reduces the incidence of diabetes by 31% (as compared with a placebo) in both men and women across different racial and ethnic groups, lifestyle intervention (including exercise) reduces the incidence by 58%. In this context, it is notable that a group of prominent medics and exercise scientists recently sent a well-publicised letter to the General Medical Council and Medical Schools Council calling for the introduction of evidence-based lifestyle education into all medical curricula. The letter warns that there is a lack of understanding of the impact that exercise and nutrition can have on physical health amongst doctors. In the absence of an educational overhaul, the signatories warn that the government is likely to fail to reach its goal of preventing tens of thousands of premature deaths from heart disease and cancer by 2020.
Whilst we agree with the need to address this apparent lack of understanding, we argue that the ethical justification of doing so is not limited to this broadly beneficence-based justification. There is also a justification grounded in the duty of non-maleficence, that is, the duty to avoid unreasonably harming patients. This duty requires that doctors refrain from (i) preventing patients from undergoing beneficial treatment without good reason, (ii) exposing patients to unreasonable risks and (iii) reducing the therapeutic effect of an effective medical intervention. This requires an understanding of the physical impact of exercise.