I am a 50 year old man and I am the same size today as I was when I was 15. People say to me ‘You’re so lucky, you never put on any weight’ as if I possess magic genes that prevent me from putting on weight.

I’m no different to anyone else. If I eat more than I need I put on weight, the same as anyone else. If I don’t take any exercise my weight will increase, just the same as it does for anyone else. So my trick, whcih isn’t really a trick at all, is to only consume as much as I need.

A key aspect of the way that I maintain my weight is exercise. I don’t do any sports, I don’t go to the gym and I don’t jog, so how do I maintain my youthful physique and remain fit and healthy? I use a technique I call passive keep fit.

What is ‘passive keep fit’ I hear you ask? Passive keep fit, for me, means getting exercise while going about my daily business. For example, rather than drive to the local shops to pick up a newspaper I will walk. And when I walk I walk fast so that I get a little breathless. My visits to the shop take a little longer than they would if I’d used my car, but then I’ve burned some serious calories in the round trip whereas sitting in the car does nothing but make you fatter.

I use the same approach in buildings with lifts. I will always use the stairs and will often run up two stairs at a time to burn even more calories. I also try to get some upper body exercise when sat in front of my computer at work by lifting myself 10 or 20 times on my arm rests a few time every day.

I also try to get a little light exercise while relaxing in front of the TV by doing a bunch of abdominal scrunches that help to keep my stomach flat. This has helped me to retain my flat stomach and six pack, much envied by my friends who all have beer bellies.

I always try to stick ot a healthy diet by eating and drinking sensibly. I try not to eat any junk food and when I do I consider it a very big treat. I actually get a lot more satisfaction from resisting temptation than I ever do from giving in. I have a pretty good idea of how much I can eat before I begin to accumulate fat so I have a habit of visualising everything that I have consumed in a day, as if it was all spread out on a table in front of me. This visualisation technique clearly highlights how many cups of tea and coffee I’ve consumed, whether I’ve eaten enough fresh fruit and vegetables and any other aspects of the days consumption that was less than ideal.

I don’t count calories, I don’t follow any sort of fad diet, I don’t work out at the gym and I don’t play any sports. Yet I am the slimmest and fittest 50 year old man that I know, and I still look OK in my Quiksilver board shorts and my cool Rip Curl T-Shirts - which can’t be bad for a many of my age.