There is a group of hip-hop dancers in Melbourne who regularly perform along Swanston Street. Most of them are wiry Asians who can bend their limbs like plasticine. But my favourite dancer is an overweight Middle Eastern boy; he pounds that concrete, every bit as fit as his skinny mates. Moving deftly through space-time, he makes the others look boring – like belly dancers without the wobble. When there’s a pause in the music he does that self-conscious thing you see blokes with bellies do: give the front of their T-shirt a little tug outwards so it hangs in front of their gut like a curtain. Women have similar moves: pulling their skirt out, or their shirt down at the back. It’s enough to break your heart, all of us walking around trying to hide.

So when I heard about Nothing To Lose, a critically acclaimed dance production billed as a radical challenge to our perceptions of the fat body, I couldn’t wait to see it. What a terrific thing, I thought, to show that one can be fat and fit, fat and healthy, fat and unashamed.

I was widely attacked by the body-positivity movement for my 2013 Monthly essay ‘Fat City’. I was accused of being moralistic and fat-hating, despite my conclusion that society must tackle the epidemic without moralising, that we must take social responsibility for creating a world where it is hard not to be fat. I still work once a week alongside the bariatric surgeons in a publicly funded obesity clinic. Patients join the long waiting list because they want help, because they are suffering the dire consequences of living obesely for decades. Their joints are destroyed; their diabetes is wreaking havoc in their kidneys, nerves and blood vessels. Their hearts are stressed and their lungs cannot clear the carbon dioxide in their blood because the fat on their torso is so heavy. When they were 20 and fat, their bodies were still healthy.

Tess Holliday is a young body-acceptance blogger and size-26 model. She has the face and the online following of a movie star. She is considered a role model by tens of thousands of overweight (mainly) women who say she has helped them to stop hating themselves, to feel beautiful.

That women’s bodies are objectified, commodified and assaulted by a media that serves corporate interests is undeniable. Beauty is culturally constructed, narrowly defined and dangled like bait in countless shops. But let’s face it, hardly anyone is “beautiful”. Most of us are average, with a few funny bits. Body hatred starts with the belief that for a woman to have worth she must be beautiful. Challenging and attempting to broaden what is considered “beautiful” is not a radical, feminist act; it is a buy-in. We should tell our daughters they don’t need to be beautiful (however this is defined) to be successful, worthwhile or happy. They don’t need to expend energy on a delusion.

France, following Spain, Italy and Israel, recently banned underweight models because of concerns that they glorify and encourage the pursuit of an unhealthily low body weight. There were a few grumbles – about the possibility of being “naturally” extremely thin or remaining healthy at these weights – but most people supported the ban. I imagine there’d be a riot if Tess Holliday were banned from modelling until she reached a “healthy” BMI. It would be seen as a misogynist act of discrimination: proof of body-hate. Fat-positive blogger Georgina Horne changed her diet and started working out. Unsurprisingly, she lost weight. There was online debate and wide censure: she’d sold out. Some of her followers felt betrayed.

I put it to you that the corporeal extremes – being very fat or very thin – are not about beauty or ugliness; they are about turning one’s back on wellbeing and longevity. If you can’t walk without injuring your knees or ulcerating the skin between your thighs, then that is a problem, however you or the world judges the shape of them. Caring for oneself is an act, not a state of mind.

It is a difficult truth that raising awareness of the health implications of obesity can cause the obese to feel pain and intensify self-loathing. So might grotesque pictures on a cigarette packet. No one wants anyone to feel like shit, but being seriously overweight is not a disease-state one is powerless to change. Will getting fit and losing some fat involve a degree of deprivation and suffering? Probably. But not as much deprivation and suffering as one may encounter in later life if one remains morbidly obese. Fat-positive activists are seriously stacking the odds against their future wellbeing. Some moderately obese people can retain cardiovascular health – those who exercise, have resilient joints and, through genetic luck, do not get diabetes (just as not everyone who smokes gets a tobacco-related disease). Health-at-any-size is possible but not probable. The current problem with our public health approach to obesity is that we raise awareness without support and leave obesogenic structures intact. Other countries are doing better: funding exercise classes and helplines, taxing crap food, investing in movement-promoting infrastructure.

I am uninterested in both the aesthetics and the morality of obesity, except insofar as they are barriers to us finding a solution to the medical and population-health mayhem obesity is causing. If we make this about identity politics, beauty and acceptance, many will end up sick. Obesity is a political issue: take a look at the socio-economic maps of its prevalence. It is about our responsibility for supporting and funding public health. It is about consumerism, and unrestrained corporate greed.

The Nothing To Lose performers did not dance. There was regal posing, strutting in underwear and the infliction of pain. They were angry and defiant, sick of being ashamed, judged and bullied. Good on them. But the obese are not a minority group in need of advocacy. They are 30% of this country. And getting very fat – like smoking or drinking to excess – is self-destructive; it is an act of body-hate against oneself. The show was moving, but the title was a lie.