January is a miserable enough month without being preached to about the powers of wheatgrass juice and the like. But there are a few simple changes you can make to your diet that will make a big difference to your skin. The simplest of these is to drink more water. I used to get really annoyed whenever I read an interview with Iman or whoever banging on about how much water they drank. But then I decided to try it. Now I glug the stuff pretty much all day, and on the rare days I don't I know about it sharpish, thanks to the tight, dry feeling of my face. It's so simple it sounds daft, but if your skin is dry, drinking water will help almost instantly.

On a nutritional front, I used to do everything you shouldn't - my diet consisted of red meat, red meat and more red meat, with the occasional potato thrown in. However, after a particularly nasty bout of gastroenteritis this summer, I turned vegetarian (well, the hypocritical, fish-eating sort). And, aside from feeling less sluggish and bloated, the unexpected bonus has been how my skin has reacted. Far from being pallid and undernourished, which was how I pictured vegetarians, regardless of whether or not they looked that way, I'm positively glowing - at least, as much as you can glow in midwinter.

It's not just me who's noticed the change, either. People have commented on how well I'm looking in that pleasing "Have you done something different with your hair?" sort of way. My skin is also much less oily, my nose less shiny and the area around my mouth and eyes less dry.

Just to make sure I wasn't imagining things, I rang Ian Marber, also known as the Food Doctor, and asked him if I was kidding myself. Turns out I'm not - well, not about that, anyway. At the risk of being sued by the entire meat industry, let's just say that cutting out meat can help to reduce your consumption of saturated fats, and too many saturated fats can lead to oily skin. So there you have it: not only are veggies smug, they have reason to be.