Well, who knew that not drinking could actually be quite simple? I was worried that I'd find sobriety a trial, that I'd be sniffing at bottles of mouthwash come day seven, swigging down mouthfuls of perfume come day 11, and eyeing up that old bucket of meths that we keep in the outside cupboard, adulterated with stray strands of paint, come day 13. But no. I've been booze-free for three weeks and it's fine. I am relieved.

And the ease with which I have given up drinking has prompted an entirely unrealistic self-confidence. In fact, I have been feeling so smug that I have started casting around for other indulgences to ditch. That's the problem with discipline - it's addictive. You give up one toxin, and start to imagine that you might become one of those people who everyone simultaneously hates and envies, a control freak of epic proportions, who eschews alcohol, sugar, sweeteners, chocolate, meat, fish, dairy, non-organic vegetables, non-organic anything, cooked food, caffeine, anything with E numbers, any additives at all, and spends at least three and a half hours at the gym each day, performing a type of yoga that gives them both glowing skin and an ability to engage in 10-hour sex marathons. Did I mention the meditation? There's always some of that thrown in, and occasionally some light chanting too. And while such people can obviously be obnoxious, and are definitely not to be trusted, who wouldn't actually love to be just like them in every single way?

Over the years I've given up quite a few unhealthy habits, with varying
degrees of success. At university I gave up chocolate for a while, and although I eventually fled back to the BP garage to stock up on Curly Wurlies, the period of abstinence did prove useful. I have never since indulged myself with quite the same two-bars-a-day fervour with which I started my university career (although I've certainly sucked down my fair share of chocolate ice cream in the intervening years).

My attempt to give up Diet Coke was even less convincing. I have a habit that runs to as many as four cans a day, and two summers ago I decided it was time to cut it out. I figured the best chance to do this would be on my summer holiday, cooped up in a converted bread oven in the Loire. And, indeed, during that week in France, the attempt was very successful. But as soon as I was back at work, I started using Sprite Zero as a substitute. What was the point? The only benefit of replacing the one diet soda with the other was that I was cutting back on my caffeine intake - but it was the caffeine buzz that I loved. After a year, I returned to Diet Coke with gusto.

Then there were my meat-and-fish-free years. These started at secondary school when I agreed to join one of my best friends in being a vegetarian. The school had only just started offering meat-free meals, and pupils who wanted them had to sit in special areas. This meant that my friend and I shared a table with five older boys, one of whom christened me Killer Cockroach (in lieu of Kira Cochrane), and spent lunchtimes pulling the wings off daddy-longlegs, then throwing their bodies into my hair.

I stayed vegetarian for more than a decade, which should have been healthy - after all, replacing meat with veg can apparently have a huge number of physical benefits. But in the short term, my particular approach to the diet did not make me feel well. All I ate was pasta, potatoes, and sometimes the two mixed together as gnocchi. Oh, and toast. After 11 years I had terrible stomach pains. I could stand it no longer. I ate half a chicken.

The problem is that, while I am quite good at giving things up, I tend to fill the gap with substances that are just as bad for me. As of yet, I haven't taken up anything horrendous to replace alcohol, but I have been finding it difficult to keep my food intake down. This suggests that I will never be a hardbody capable of doing 5,000 sit-ups each day at 5am, before breakfasting on cardboard. I'm just going to have to learn to live with that.