Will we go to pot like Barnes?

Who ate all the pies? The latest person at whom the merciless football chant could be levelled is former player John Barnes. Barnes, now 39 and with his playing career behind him, was always a big chap, but a photograph of him shopping at the weekend revealed the awful truth - he has run to fat in a big way. Where once a Liverpool or England shirt flapped across his muscular chest, a jersey clung to his pillowy stomach and his thighs, formerly sculpted from solid muscle, were a shade too large and rounded for his trousers.

It's never easy when a footballer stops training five hours a day, and there are many examples of how ultra-fit sportsmen can become overweight - Brendan Foster, the long-distance runner, is huge now - and Gazza never looked slim at the best of times.

John Barnes enjoyed 10 years of brilliance at Liverpool FC between 1987 and 1997, and also gained 78 international caps. Now his main role involves sitting on a sofa as a TV football pundit - and we all know what sitting on the sofa can do to one's physique.

Unfairly, the super fit are more susceptible to piling on the pounds when they stop training. They consume huge amounts of calorierich food to fuel their energy-burning activities and it is difficult to break the habit. It is a simple equation - energy taken in (calories) versus energy expended (exercise). Any surplus and the body stores it as fat.

"In normal training, a footballer needs up to 5,000 calories a day - twice the amount a man with a desk job needs," says John Brewer, director of the Human Performance Centre at Lilleshall, part of the National Sports Centre, in Shropshire.

"When he stops playing, he needs to halve that. It's a big problem, and even more so for rowers such as Steve Redgrave, who could need up to 7,000 calories when in training. It's a double-edged sword, because if you're not playing, you have more time in which to eat and drink."

"If your body is used to doing a lot of sport, your appetite goes wild," says Michael Garry, a personal trainer based at the Claridges Olympus Suite. "It's much worse for footballers than people who have never trained to that extent. These people live sport 24 hours a day. If they become sedentary, their bodies still crave calories until they strike a balance between what they want and what they need."

There are lessons for the rest of us, however, because as we get older we need fewer calories. Males between 15 and 18 need 2,750 calories a day on average, and this figure falls with age by approximately 100 calories every 10 years.

We need less fuel because our metabolic rate slows with age; there is a natural muscle wastage in men aged over 40 - and muscle mass burns calories; and people gradually become less active.

Even if we don't have to make the huge reduction in our calorie intake that a sportsman faces, we need to adjust our diet as we grow older and slow down, often switching from high-octane activities like squash to bowls or golf. But the popularly held belief that muscle turns to fat is simply not true - though that is what it looks like to the casual observer. An ultrasound probe against the body shows clearly how muscle, fat and skin form separate layers. What makes the difference is the relative thickness of the layer of muscle to the layer of fat.

"When a sportsman retires, he is usually in his late thirties or early forties," says Garry. "That's the stage at which the body starts to lose muscle and store more fat. As well as reducing calories, former sportsmen should keep some exercise going, especially weight training, because that maintains muscle bulk. They should also do cardiovascular work, such as jogging or cycling three times a week. The main thing is to get the correct balance to avoid gaining excess weight." David West, a physiotherapist who heads the Metis Clinic in Croydon and has worked with many top football players, explains why many fail to keep off the excess weight.

"Old injuries tend to catch up with players once they retire. While playing, they can keep their joints mobile and strong, but as soon as they stop and are not getting regular physio sessions, aches and pains come to the fore. They can't exercise as much as they used to, nor enough to stop the weight piling on. The older players we see, who are coming up to 40, all suffer the same things - their joints won't allow them to do what they used to."

In which case there's nothing else for it, but fewer pies - sorry, John.

www.lilleshall.com; Michael Garry, 07958 302 798; Metis: 020 8664 1720.