Rhiannon Harries: 'Addiction's never good for you – even if it is 'good' for you'

Every time I leave the gym, tired, horribly dishevelled, but essentially satisfied, I think it is going to happen. This is such a great feeling, I think to myself. Better than anything I get from a cigarette or glass of wine or extra hour in bed. I'm going to remember this post-work-out elation and crave it so powerfully that I will be compelled to come to the gym every day for the rest of my life.

Except I don't. However much I might want it, this exercise addiction won't kick in. Not so for Amy Winehouse, though: "She's in the gym three or four hours a day. I mean, boy, is she fit, really, really fit," blustered the singer's media-friendly dad Mitch to the papers last week. "So that's a really positive addiction."

It's impossible to make a comparison between taking class-A drugs and hitting the treadmill, so it would be unfair to expect her father to see this as anything but a change for the better. But since she's a singer, not a professional athlete, spending a quarter of her waking hours exercising is not normal – nor is describing any kind of addiction as positive.

Albeit unwittingly, Mitch raises a good point, though – addictions and obsessions per se do enjoy an oddly neutral status. It's their object which decides their position in the realms of either good or evil. Compulsive eating, for instance, inspires blanket revulsion. An addiction to drugs or booze wins a mixed bag of disapproval and sympathy with a vague patina of glamour or romance. Meanwhile, obsessively exercising, regulating one's diet or working generally get the green light as normal, even enviable.

The replacement of a dangerous addiction with a less harmful one is a standard trajectory. A friend who was anorexic as a teenager is now a wheat-free, dairy-free, sugar-free kind of girl who freaks out if she doesn't get a couple of hours of yoga in by 8am. The physical danger has been mitigated, but whatever the inner machinations that fuelled her anorexia were, they are still alive and kicking. Yet somehow she is taken by many to be the picture of good health, even though she's only packing 50 per cent of the old mens sana in corpore sano adage.

So next time you hear that a Hollywood star gets up at 4am to go to the gym or allows nothing but seeds and berries to pass their lips, stop fantasising about having similar self-discipline and wish for nothing more than good old-fashioned, middle-of-the-curve moderation.

I, for one, shall be bearing Ms Winehouse herself in mind next time I'm on the treadmill: better not push it too hard; could be a slippery slope...