Tim Key: I wanted to sign up to the gym and become slim and handsome

I've just come back from the gym and I'm absolutely exhausted.

I haven't really done anything in terms of exercise for a couple of years now. I put my back out stamping on a towel in 2012 and it's taken me this long to recover. A couple of years before that I was a member of a gym, and recently I've been daydreaming about having a nice body. Then I had a conversation with a girl who does circuit training. Her face was so thin and muscly, and all because of her hard work. Twice a week she goes to the gym and absolutely exerts herself until she is sweaty and her arms bulge. Her story was an inspiration. I grabbed at the rolls of fat under my chin and, about a month later, I waddled down to my local gym.

I arrived, caught my breath and explained to the svelte lady behind the desk that I wanted to sign up and become slim and handsome. She smiled at my body and said that she'd get someone to talk it through with me. I didn't like it. I'd had visions of just paying her some money, her giving me a little membership card and me being on my way. But that wasn't the way they did things here. I had to wait at a table for someone to "assess my needs".

After a bit, a stacked man came out with a tight-fitting T-shirt and a pen. He introduced himself as Derreck and sat opposite me clicking his pen in and out, and occasionally asking me a question or smirking at my lack of conditioning.

"What are your goals?" he leered.

I muttered some optimistic things like "thin" and "strong" and "rock-hard abs".

He nodded and ejaculated a half-grunt/half-laugh, and held the list of tariffs up over his face to hide his smile. The guy worked in a gym, and boy did it show. He had clearly been sneakily using the equipment in his breaks and now every part of his body oozed brawn.

I don't own a car, but the more he asked questions, and the more he examined my torso and scrutinised my anaemic calves, the more it felt like an MOT. He was assessing me, like any good mechanic would. Tapping my biceps, pinching my flanks, crouching down and peering up at my hips. Occasionally he would suck in a judgmental breath and tut. The implication was that this particular car was in very poor shape. That it would take a lot to get it back on the road. That maybe it wasn't worth his while fixing it at all. We did a tour of the gym.

Everywhere you looked bodies pumped iron. Dead-eyed meatheads leaned over water fountains. A topless man draped himself over a gigantic ball.

We stopped by a girl. A man with a denim bandana was bawling at her. He was making her work her tits off. Even though she was trying really hard, he was insisting she gave him even more. Her cheeks were puce and her back glistened as her singlet stuck to it. "You can get a personal trainer," said Derreck, again with a layer of sarcasm that I didn't much care for. I looked down at his tariffs.

Once she'd thrown up and showered, this poor creature would be paying her tormenter £45. I was sweating profusely. I needed water. This place was horrible.

The tour finished and Derreck delivered me back to the lady behind the desk. I was wheezing from the two flights of stairs and the horrors I had witnessed. She had highlighted a tariff and again gestured to my body, this time not smiling. I felt a stitch kicking in from the tour but tried to style it out. There was an impasse.

I handed over my debit card and plunged my hand deep into my tummy. I typed in my pin and walked home, grabbing on to street furniture when I felt like I was about to black out.

And now I'm on my sofa. A member of a gym. It's the first day of the rest of my life.