Written by Alan Barker, Freelance Writer, British Science Festival 

Being obese is unhealthy, yes? Well, not quite. And it certainly isn’t an ‘epidemic’. Dr Oli Williams of the University of Leicester believes that we need to rethink our approach to weight. In the Margaret Mead Award Lecture for social sciences at this year’s British Science Festival, he challenged some of our most fundamental assumptions about obesity. Alan Barker set aside his jam doughnut and sat in.

Oli Williams doesn’t just study the world. He wants to change it. And he wants to start by changing the way we look at it. In this year’s Margaret Mead Award Lecture at the British Science Festival, he presented his thesis up front and bold.

Our approach to obesity, he says, is unfair, ineffective and needs to change.

Being overweight has become a major health issue in the last few decades. The incidence of obesity has risen; but the rise depends, in part, on how we define and measure it. The BMI index, Oli told us in typically epigrammatic fashion, is what makes obesity possible. Medical professionals like its simplicity, but the presentation of the index by health authorities creates the impression that obesity is a disease. In fact, BMI is an extremely inaccurate predictor of health. Oli doesn’t deny that obesity is associated with increased risks of type 2 diabetes, heart disease and cancer; but the biggest threat to public health posed by obesity, he claims, is our approach to it.

A healthy obese person is a contradiction in terms, yes? Well, not really. Oli set out three so-called obesity paradoxes. The first we might call the rugby paradox: because the BMI index doesn’t distinguish fat from muscle, a burly super fit rugby player is likely to be classed as clinically obese. Secondly, obese people tend to recover better from heart surgery than others, perhaps because the extra fat offers the body greater protection. And then there are the 'Fat-but-Fits': people sitting in the obese category of the BMI chart who exercise frequently and show many signs of good health. In fact, Oli, told us, physical activity is a much better predictor of health than BMI. Our obsession with weight loss is misplaced.

So should public policy focus on exercise rather than weight? Oli wrong-foots us again. By telling us to exercise more – and indeed to eat more healthily – government campaigns make weight a matter of personal responsibility. We become seduced by a dangerous argument. Obesity equals ill-health, and health is a personal responsibility. Therefore, anyone overweight is irresponsible and a drain on the NHS (to the tune of £6.1bn a year, we’re told). Fat becomes a metaphor for moral turpitude.

In fact, all the signs show that health is intimately linked with wealth. Every health indicator shows what sociologists call a social gradient: access to good food and the means to exercise are socially and economically determined. But Oli is realistic enough to acknowledge that redistributing wealth – which would be the best way, socially, to address the problem of obesity – is unlikely to happen any time soon.

Instead, people are offered weight-loss groups. And Oli has studied these groups very closely. Participants are encouraged to focus obsessively on losing weight, a process that is unpredictable, challenging and emotionally draining. The rhetorical equation – obesity equals irresponsibility – loads the whole process with stigma, which becomes physically embodied in the participants themselves. One of the most sadly ironic symptoms is an increased level of cortisol – one of the chief functions of which is to store fat in the body.

Oli’s solution to this raft of problems is to offer support, not stigma. That’s the message of The Weight of Expectation, a comic book he’s created with Jade Sarson, telling the story of how obesity stigma becomes felt in the flesh. It’s a project developed by Act with Love, an art collective set up by Oli and his brother, who’s a graphic designer, to promote social justice and – in their words – “to address the shortcomings of their respective occupations.

Find out more about the British Science Festival here.