When I passed the 11 plus in 1972, my mum sent me to tea with Charles. Charles was the other boy in my class who would be going to the grammar school that autumn. So my mum and his mum thought we should be mates. It didn’t really work out that way, although I did buy my first single from Charles. American Pie, 45p.

The thing is, Charles and I were very different. In lots of ways — and one in particular. I was thin. Charles was fat. I remember he was fat because in those days it was so unusual. There were more than 100 boys in our school year. Only two others were fat. I can remember their names too.

I’m still thin. I’ve never been anything other. I’ve managed to stay as thin as I am in middle age because I run. I normally have a BMI of under 20. Right now it’s hovering above that because I’m injured and out of sorts. Far from being overweight, at my fittest, I’m usually close to the opposite.

What does that amount to? Luck and intention — a combination that works. But it doesn’t make me a saint. And it certainly doesn’t give me the right to call out others who weren’t blessed with that luck or whose intentions have fallen on stony ground.

Some of my nearest and dearest are overweight. They all know better than I do that they need to do something about it. It doesn’t make them bad people. And it definitely doesn’t mean they should be publicly pilloried. No one’s harder on them than they are themselves.

Paul Gray, the Director-General of Health and Social Care and the Chief Executive of the NHS in Scotland is seriously overweight. He’s said so on Twitter in response to being called out and told to set an example by the Chair of the National Obesity Forum, Tam Fry. And it’s now a story in The Herald by Stephen Naysmith.

Full disclosure. I’ve met Stephen a few times and always found him to be a thoughtful and compassionate journalist. I’ve not met Paul but we’ve exchanged the odd message on Twitter. Perhaps I should have done, but I’d never heard of Tam until this story broke.

Obesity is a serious public health problem worldwide. And amongst the most serious facing us in Scotland, with 65% of the adult population overweight and 29% obese at the last count. Being fat is costing us billions. And it’s killing us. So this is no time to be squeamish about naming it.

But name calling people to make an example of them because somehow they have a responsibility to be more responsible than the rest of us? No. Sorry, that just won’t do. It’s entirely the kind of moral rectitude than sends people scurrying to the hills and beyond. It doesn’t work — for them or us.

Don’t get me wrong. I’m all for plain talking. I think we do need to talk about fat. Words like obese and phrases like body mass index can get in the way. So by all means, let’s talk about it. But let’s not make it personal.

When I was at school with Charles, my mum would say that I shouldn’t talk about him being fat. ‘It’s his glands’ she’d say in a whisper. My granny called it ‘big-boned.’ My mum was right — and wrong. She was wrong about the glands thing. It was just a euphemism.

But she was right too. It wasn’t my place to comment on it and it would have been cruel to taunt Charles. That was off limits. I didn’t really take too much persuading. I was so thin I was called a weed. It wasn’t nice. Jibing isn’t. Especially when you’re a kid.

Charles was almost certainly fat because he ate too much and didn’t get enough exercise. That’s the case for most people who are overweight. Put more in than you burn off and you get bigger. The multi-million pound slimming industry somehow manages to obscure that essential truth.

It sounds so simple — and in one sense it is — yet human behaviour is anything but. We’re complicated. All of us. Pretending that it’s easier for people just because of the job they do is nonsense. And it’s what they do that counts.

This isn’t intended as a defence of Paul. I’ve no brief for that and he’s more than able to speak for himself — as indeed he already has. It’s not intended as a personal attack on Tam or Stephen either. They are doing their jobs in the way they choose. I just don’t agree with them.

For me, this is about what’s decent, kind — and relevant. It takes all sorts to make a world and none of us is perfect. But you can’t hide being fat. Covering obesity is in the public interest. But there’s nothing to be gained from exposing people in the process.

With 29% of Scottish children at risk of being overweight and 14% at risk of being obese, fat is no longer the rarity it was in the playground when I was a kid. But bullying is as rife as ever. So if we’re talking about setting an example, we’d do well to stick to the issues and leave individuals alone.

Obesity is one of the curses of our time. It’s also significantly linked to inequality. And despite all the advances in science we’ve brought it on ourselves. That’s shameful and it needs drastic action on the part of institutions — public and private.

We need to stop dribbling the ball at the edge of the pitch and score a few goals. Personally, I’d start with the food industry. This is no time for worrying about whether the state should be nanny.

It needs serious endeavour on the part of individuals too — diet and exercise matter. But whoever we are and whatever we do — that’s our business. And it should stay that way.