I have just been to a lecture – whose title I’ve stolen for this blog – given by Inez de Beaufort, Professor of Healthcare Ethics at the Erasmus Medical Centre in Rotterdam. Subtitled ‘Ethics, obesity and public health’, and organised by the Nuffield Council on Bioethics. Professor Inez was after teasing out some of the ethical issues raised by the great tide of obesity that is engulfing us. Is our weight solely our own business, a matter of personal choice, an expression of lifestyle or is it something the state needs to take an interest in? If we are overweight, is it a matter of poor choices, of over-indulgence, of moral failure – what Aristotle identified as the problem of akrasia or lack of self-command: why should anyone willingly go towards the bad? – or is it the result of factors outside our immediate control: our genes, our social class, our ‘obesogenic environment’? And if the state is to show its hand, what should it do? Should it treat us as economic rationalists and tax us out of our fondness for fish and chips? Or should it see us as genetically – or socially – driven to take second helpings and do something more paternalistic, somehow forcing us out of our cars and onto our feet and our bicycles?

Much contemporary medical ethics has to do with the doctor-patient relationship. It is individualistic in character, focussing on the needs and interests of individual patients. Its mantras are consent and autonomy, confidentiality and informed decision-making. It is aligned with the political liberalism of which it is also an expression. Throughout much of it can be heard John Stuart Mill’s ringing defence of individual freedom, his one simple principle, ‘that the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is for the protection of others.’ While such a principle often holds good in individual consultations, it begins to creek and groan a little when the matter in question is the health of communities. Obesity is of course a matter for individuals – do I or do I not have a doner kebab after the pub, do I or do I not go on a cabbage soup diet – but it is also a matter for populations: a staggering thirty-four per cent of adult Americans are said to be obese. Public health issues like obesity also raise a well known problem for Mill’s principle. If the prevention of harm to others is the only reason the state can interfere with personal choices, what counts as a sufficient harm? Is the burden of obesity – it’s health and social cost – sufficient to warrant intervention, and if so, to what extent?

The politics of liberalism also relies upon a certain understanding of what a human being is: an autonomous limited subject capable of rationally pursuing her own interests on the basis of freely chosen life-plans. Obesity again presents a challenge to such a view. Given the health impact of obesity alone, how can it be in anyone’s interests to be obese – akrasia again – which of us chooses to be fat? Obesity points instead to a more divided view of the human subject: which of us has not at times put immediate gratification – oh go on then just one more glass – before our longer term and therefore perhaps less keenly felt best interests?

Although the talk remained firmly among liberals, one question asked at the end had me thinking. It was about stigma. For liberals stigma is a bad thing. If the way we are is the result of freely chosen life plans, and, because we are all equals, no one life plan is better than another, it surely follows that stigma, and its associated emotions, shame and distaste, have no place in the liberal universe. But there is a difficulty here. Stigma is the result of moral evaluation – of calling a thing bad. The surest way to remove stigma is to re-evaluate something, to turn it from being bad to being good. But if obesity ceases to be a bad thing, how do you motivate people to avoid it? Weight is a matter of great personal sensitivity, and as civilized souls we shrink from giving offence. But if obesity presents the public health challenge we are led to believe, we are in for an uphill struggle if we fight shy of judgment.

Julian Sheather is ethics manager, BMA. The views he expresses in his blog posts are entirely his own.