UCL in the News: Food for thought. What Britain's top brains eat

Are greens good for the grey matter, or will egg and chips do just as well? Top boffins reveal their eating habits Steve Jones is Professor of Genetics at University College, London.

His writing on evolution won him the prestigious Royal Society Michael Faraday prize, and his work as a biologist led to his becoming a vegetarian.

We live in a unique time in history from the point of view of diet because for the first time the poor are fat and the rich are thin. It's quite arguable that my generation is going to be the longest-living in history because the next generation is suffering from the plague of obesity, which is going to shorten life expectancy by a lot. There are thousands of scientists working on obesity and there's a thing called the Human Obesity Gene Map. The last time I looked at it there were 560 candidate genes for obesity which means everybody has got some of them. What causes obesity? Overeating. I was talking to Sydney Brenner, who won the Nobel Prize in 2002, and he said, 'Steve, we discovered the gene for obesity years ago: it's the one that makes you open your mouth'.

I'm always asked, 'Do you eat snails?' I started collecting them as a biology undergraduate in the Sixties and, the last time I looked, I had killed about 400,000, so when I'm asked the question I know the answer in about 15 different languages. In fact, I haven't eaten snails since about 1985. For one thing, I find them really quite beautiful and elegant, but I just don't like the taste and I know what they eat, which can be pretty disgusting.

I'm also a vegetarian now and have been pretty much since I went to teach at the University of Botswana in the mid-Seventies. On my first day in the country I ended up with a group of students at the largest slaughterhouse in the southern hemisphere. Botswana is a very big cattle-rearing country and we went to this very well-run place - these poor cows going 'Moo' and getting shot and then opening them up to look for gut parasites. I am a biologist, I've cut up plenty of animals, so it doesn't really worry me - I was splitting them open, pulling out tapeworms. But I kept hearing these heavy thumps and, I turned around, it was the students fainting: donk, donk, donk. I suddenly thought, 'You know something, I don't think I'm going to eat meat again', and I never have.

I eat lunch every day at the student cafeteria at UCL, and have done for almost 30 years. I always have the same thing, a boring vegetarian salad. When I'm working I want lunch to be as simple as possible. The mathematical philosopher Wittgenstein came up with a phrase I often think of: 'I don't mind what I eat, so long as it's always the same thing.' What people fail to understand about science, particularly biology, is that it is tremendously repetitive. If you are studying DNA variation, it involves coming in every morning, putting on the same goddamn lab coat, doing the same complicated, linear series of things, often 40 or 50 steps, and if any one goes wrong, that's it, the day's wasted. You do this for hundreds if not thousands of days, one after another. So when it comes to lunch, you don't want to think too hard.

I come from a very ordinary lower-middle-class Welsh family, and growing up, I never thought too much about what I ate. When I was an undergraduate in Edinburgh, I began the Scottish Suicide Diet. I would get up at noon and have a pork pie and four cups of coffee, then I would have fish and chips for lunch and a Mars bar at 3am. After 10 years of that I thought, 'Maybe this isn't wise'.

The reason I enjoy cooking now is that when I was doing my PhD, I used to go off on field trips where you were in the middle of nowhere and were forced to cook. Lots of field biologists are like that.

I do most of the cooking at home, but I'm not averse to going out and spending a fair amount of money on a meal. A couple of years ago I went with my wife and her cousin to - what's that one in Chelsea? I think it's Gordon Ramsay. I have never got nearer to getting up and punching a waiter in my life. The food was very good - it was a bit mucked around for my tastes - but if there's one thing that drives me mad it's having a meal as if you are in intensive care. In other words, little metaphorical bleeps going on all around you, people with grey faces waiting for the next crisis. If that's what you want why not get hooked up to a drip in hospital to go through the full experience?

Tim Lewis, 'The Observer'