It's all too easy to look for excuses when we pile on a few extra pounds, but have you ever considered that watching too much television could be to blame?

It seems like the most natural thing in the world; slobbing out in front of the television after a hard day at work. But recent research has proved that people who watch around two hours of TV per day are 93 per cent more likely to be overweight than those who watched only half an hour per day.

You might wonder why watching TV piles on the pounds - after all, many people sit down all day at work. So what's the difference? Well, the bottom line is that watching television is literally the laziest thing you can do.

Let's get an expert to explain: "When adults watch TV they are virtually motionless. Research has shown that your heart rate, blood pressure and metabolic rate decline, resulting in burning 20 to 30 calories less per hour," says Tom Farley, M.D., chair of the department of community health sciences at the Tulane University School of Public Health and Tropical Medicine in America.

So let's do the maths. By watching five hours of TV per day - that's only watching from 7.00pm until midnight - the reduced burn in calories could mean you put on a pound of weight each month. That's a whopping 12lb a year - and don't forget any extra pounds from all of the extra snacks we consume while watching the box.

This isn't just a problem that affects adults. Parents in America have been advised not to let their kids have a television in their own room because of the risk to their health. Research has proved that watching two hours of TV a day increased a child's chance of becoming obese by 23 per cent. And many children regularly watch three to five hours per day.

Furthermore, it's not just piling on the pounds that we need to worry about. A recent study showed that two hours of TV per day increases your chances of developing type two diabetes by 14 per cent. And again this isn't just due to inactivity; lack of exercise can contribute, but not to this extent.

As adults we might think we're less prone to falling for the advertisers' charms, but how many times have you seen chocolate on a TV advert and then just had to have some?

Research by top US university Harvard has shown that there's a link between the amount children eat and the amount of television they watch.

Jean Wiecha, one of the report's authors, says: "The perception is that children watching television only gain weight because they are sitting and snacking in front of the screen and doing less physical activity, but when we compared the children's daily calorie intake at the end of the study with what they were consuming at the start, the majority of the increase in calories was explained by them eating more of the snack foods they had seen advertised."

Adults are just as prone to eating junk while watching TV. What are your favourite TV snacks? Popcorn? Chocolate? Crisps? All high in calories, salt and saturated fats. And while we're at it, if you're watching television all evening, you're probably eating a ready meal rather that cooking and eating a healthy balanced meal.

So what can you do to combat the television-induced piling on of pounds? We're not suggesting you turn it off completely, but here are our top tips for trying to reduce the negative effects.

• Check a TV programme guide and work out what you really want to watch, rather than switching it on at the beginning of the evening and watching whatever comes on

• Do something else while watching TV - the ironing, dusting etc
• Use an exercise bike in front of the TV
• Make dinnertime TV-free - it's a great time to talk as a family
• Put TV snacks in small bowls rather than sitting with a big bag of crisps on your lap
• Put a fruit bowl near the sofa and munch your way through that