Well, I think. This is an awkward situation for a man.

'OK,' says Gary, who I've just realised deserves his anonymity, so let's call him Barry. 'Those are your measurements done.'

He puts the tape down.

'Let's get on with it!'

Barry is my brand-new personal trainer. I don't imagine that's his only job - he probably trains other people, too - but today he is mine, and it's his mission and duty to recondition my tired and aching body. I have never been any good at exercise. I have always been very bad at it. But maybe this will change things.

Hopefully, I think, this will not take much more than a day.

My decision to employ Barry was not one I saw coming. But lately, something's been ... changing. I mean, in the past, I've heard fellow gentlemen talk about looking in the mirror, at their slight paunch or their slowly retreating hairline, and thinking, Well, this is it ... this is literally the best I will ever look, and then giving up on life and buying jeans with drawcord waists and a trowel. And I've talked to other men - men just two or three years older than me - who've stared at me in shock and disgusted disbelief and said, 'What do you mean, you don't have a "takeaway night"? What do you mean you just have them unplanned?'

But none of this seemed to relate to me in any way. Not until last week. Last week, when I passed a billboard shouting about a 'Revolution' in 'Personal Training!' Last week, when I stood in the rain and stared at it. Last week, when I stared at the Big Mac, damp in my hands, and wondered whether something had to give.

Last week, when I turned a year older.

'Well done, mate!' I hear, suddenly. It's Barry, who I think I'll start calling Gary again. 'Well done!'

Gary seems delighted at my progress. Already, I have done ten sit-ups, and later, I plan to do an eleventh. We move to the weights, and I seem to be very good at those, too, and Gary claps his hands together, and says 'Well done!' From nowhere, I am filled with a manly enthusiasm for the task ahead. Why didn't I do this years ago?

Unless ... no.

Gary does not seem the type to say 'well done' to everyone. In his job, you've got to shape up or ship out, and it doesn't pay to encourage the ones with no natural talent for these things. Gary told me well done on the rowing machine, too, so it seems I'm great at rowing, and now that I'm on the treadmill, he seems more than quietly impressed.

'Excellent work,' he tells me, as I replace literally the first dumbbells I have ever touched. 'Really well done.'