Since we began this health and fitness drive, we have changed many of our habits, but not – naturally enough – our family, friends and colleagues.

We thought about it, but decided it was a little extreme and, probably, not worth the hassle.

However, something didn’t quite add up. We’ve been hanging around with thin people who shouldn’t be thin – all things being equally weighed.

These are thin people whose eating habits, and pride in a lack of an exercise routine, should result in them being far wider than they are.

We’re learned recently that people in this category are called “skinny-fat” – proof, surely, that a term now exists for absolutely everything.

If you’re blessed with a body that can eat a horse while maintaining the figure of a boa constrictor, then, well, good for you.

If you can go through life easily maintaining a lean figure without knowing that a cross-trainer is not an ill-tempered gym instructor, then – and we’re saying this through gritted teeth – good for you.

We probably should be happy for them. And, sometimes, we are. But then we think about all the effort that the “fat-skinny” put themselves through – and all the nice things they deny themselves – to get to a shape that many of the population can acquire with little or no effort. It is simply unfair.

I’m still twice the weight of my wife (who has never seen the inside of a gym). If I eat a bag of chips, I put on a few pounds. If she eats a bag of chips, I put on a few pounds.

Not all skinny people are skinny-fat of course, and it’s difficult to know how people stay slim. It seems as inappropriate to ask someone how they stay so skinny as it is to ask someone how they’re so damn fat.

There are, it seems, very healthy skinny people, and very unhealthy skinny people. When I started this fitness and health drive I was in no doubt I was leading an unhealthy life, mainly because my food choices were based solely on taste and convenience, and I treated exercise as an infectious disease (just to be safe, it was considered best not to hang around with those who suffered from it).

But it was also beneficial that no one thought it necessary to tell me to eat more chips and burgers. And nobody queried why I would consider exercise to be necessary.

If a slim person exercises, they are questioned as to why they do.

Thin people are told they need to eat more, and are pressed to eat unhealthy foods because . . . well . . . for God’s sake put some fat on those bones.

Some are already fat, just not on the outside.

While the BMI is probably very low, skinny-fat people may have the metabolic features of a pre-diabetic obese person – low muscle mass, high blood sugar and blood pressure.

At least, if you’re overweight, you are aware of the dangers. But as a society we have regularly and incorrectly associated being skinny with being healthy.

This column has been guilty of it as well.

The target has always been to be healthier and fitter. However, naturally, losing weight has been one of the prime visual targets – no bad thing.

But we’ve put too much weight on weight.

We should be satisfied that we’re a little healthier as a result of our better eating and exercise habits.

Though, sometimes, we’d rather have a metabolism that’s able to hide all evidence of cheese burgers.

Damian’s Stats

Age: 40

Height: 6ft

Weight: 14st 2lb (minus 2st 5lb)

BMI: 26.8 (-3.6)

Fat: 25.5% (-4.1)

Figures in brackets indicate change since March 10th, when Damian started to change his diet and exercise habits, and write this column.