Christie is the only man to have held the World, Olympic, Commonwealth and European 100m titles simultaneously. Since his retirement from athletics in 1999 he has focused on coaching.
You've kept yourself in great shape. What's your secret?
"Everything in moderation. I don't diet because I think when you deprive your body of something, that's when it wants it most."
Do you still exercise regularly?
"Yeah, I train fairly well still. I run and I do a lot of weight training. I coach and that can be pretty intense. I'm an exercise junkie. If I don't do anything I feel a bit down. I've got kids too and when you're running about after them you get a pretty good workout."
What do you eat on a typical day?
"I only eat when I'm hungry. I tend to snack on fruit. It's a bit of an addiction. I always have breakfast, either muesli or I do the old egg and bacon thing, but I always grill the bacon. I have lunch if I have time, but sometimes I've eaten so much fruit that I'm not hungry. For dinner, I have to have a proper meal. I love white meat or fish, cauliflower cheese and broccoli. I don't eat red meat."
Do you drink alcohol?
"I don’t touch it at all. I don't like the taste and when I was growing up, my parents never drank. I've never got into it."
Why do you think we are getting fatter as a nation?
"We're lazy. We sit in and watch rubbish TV about other people's lives rather than going out and being active."
Obesity in young people is a big problem. How can we fight it?
"Families don't do enough together. Get up and do things as a family. Go for a walk or go to the park. We have some of the best parks in the world so people should get out there and roll around a bit! Make up some games or play the games you used to play as a kid."
Are there any 'naughty' foods you indulge in?
"I like crisps now and again. I don't really like chocolate, apart from white chocolate."
What about middle-age spread? Is it inevitable or can we fight it?
"Well, I still try to fight it. I say, be vain! Go down the gym and take care over how you look. Middle-age spread is something you can avoid. Slow metabolism is just an excuse. Having kids makes you think about getting in shape. I want to be around to see my kids get married, and their kids too."
Do you have advice for people who are new to exercise and scared of using the gym?
"Try going for brisk walks and swimming or cycling. They're just as good for getting you fit and are cheaper than the gym. And there are exercises you can do at home, such as push-ups and sit-ups. Play with your kids or grandchildren. Jumping around like that keeps you going. Exercise with your partner and train towards something."
What if people don't have gardens or parks nearby?
"Even if you've only got a little space, you can put in a trampette. They're fun and really get the heart rate up."
What's your mantra for a healthy lifestyle?
"Do a little bit of exercise every single day. It can be anything. Start today. Don't put it off until tomorrow."
