I used to be fat. (You still are, say the wags.) But I mean really fat. Shopping-at-specialist-internet-clothes-stores fat. Heckled-in-the-street fat. It wasn’t fun, but it took years before I had the willpower, the courage or some combination of the two to do anything about it.

By the time I was 24, in 2008, the feeling that I had to lose weight had been growing for some time. It is impossible to identify one event that prompted me to take action. Was it preparing to change jobs for the first time? Was it the last photo taken of me and my grandpa, which I couldn’t bear to look at? It was everything and nothing. All I knew was that my life didn’t feel worth living if I didn’t make a change.

Of course, not all fat people are unhappy or want to change, and the science around weight is very much contested. But, for me, it suddenly felt very urgent.

What I did wasn’t complicated or revolutionary. It involved years of helpful amateur “advice”, diet shows on TV and useful tips from gym-bunny friends. The idea was to eat less and exercise more – with a clear emphasis on the former.

I was incredibly disciplined about what I ate, buying healthy options and cooking in advance, and I went to the gym at least twice a week. It is not easy walking into a mirror-strewn room full of pumped-up people when you weigh more than 160kg (25 stone). But it was liberating to realise that those six-packed Adonises were far more interested in their own reflections than me huffing and puffing behind them. No matter how close you get to “the ideal body”, insecurity lurks.

Toby Moses (right), before his weight loss, with a friend.

All of this will be familiar to anyone who has thought about losing weight. But that is not the change that mattered the most. It was my willingness to embrace a social life that had hitherto felt onerous, but which empowered me. I knew that being home alone was when my worst habits became irresistible. So, I decided to make sure it happened as rarely as possible. I booked out every night when I wasn’t going to the gym with some social event or other. Being around people was meant to provide an insurance policy against my failure of willpower. But it was helpful in other ways that I had never imagined.

It wasn’t easy, though. All my adult life, leaving the house had been fraught with anxiety. If you have never been fat, the idea that people in passing cars might shout at you in the street simply for being chubby may seem unlikely. It isn’t. It happened to me a lot. And the excruciating embarrassment when it occurred in front of a friend was hard to bear. The forced: “Did you hear that?”, “What did he say?” brought the elephant in the room crashing into view.

Then there was the worry about where we would go. Would I fit into the seat? Would it involve a tiring walk? What if a stranger decided to take the piss? I was by no means a hermit, but I would often stay in when I couldn’t face the outside world.

But rather than terrorising me, going out became part of the solution. Nobody knew. The thought of sharing what I was doing was too scary. That soon became impossible. As the pounds fell off, people started to notice. But that was suddenly OK, because my confidence had increased, the comments occurred less often, and walking became a pleasure – it was exercise.

Relying on a social life to get through forced me to lean on friends in a way that I never had. Talking about myself gradually became easier. I was able to let people in, I was less spiky and my relationships improved. It wasn’t easy, but I don’t remember the difficulties of disciplined eating and social anxiety so much: it is the happy memories I made that have stuck.

Eighteen months later, half the weight I was before, it wasn’t just physical weight that had been lifted from my shoulders. Going out for the night was no longer scary. I didn’t need to plan any excursion to the nth degree to feel OK. Not all my worries disappeared, but a big chunk of them did – and it was a blessed relief.

“Adopt a strict diet and exercise more” is the usual advice for anyone who wants to lose weight. That can feel impossible – it did to me for a long time. But sometimes it is changing the smaller things that can help you get where you want to go. Positive change need not involve sacrifice or pain – sometimes it just means a trip to the pub with some mates.