Britain has among the highest rates of obesity and lowest levels of exercise in the world, yet research shows that we are also one of the top consumers of sports drinks and foods in Europe.

The UK spent £180m on products branded for athletes in 2005, and the market is one of the fastest growing in the consumer industry, according to a report by the analyst company Datamonitor. The sports food and drinks market is growing at 30 per cent a year, far outstripping growth of the consumer industry as a whole. By 2010, Britons will be spending £235m annually on high-energy sports bars and drinks. Only the Germans and Italians are bigger consumers of sports food and drink products in Europe, the research found.

Experts warned that many consumers were buying into the celebrity- endorsed brands in an effort to feel healthy, without realising that some products may have as much sugar as a bar of chocolate. Sports drinks may contain as much sugar as a regular fizzy drink because they are designed quickly to replace lost energy.

One in three Britons has bought a sports drink in the past six months, despite the fact that only one in five people exercise in line with the government recommendation of at least half an hour, three times a week. One in four adults and one in five children in Britain is now overweight or obese.

John Band, author of the report, said: "Fifty years ago, people kept slim because they walked to work - nowadays they drive to the gym, do some exercise and go to the sports centre café that sells these drinks. People who aren't doing exercise buy them because they feel that by doing so, they are buying into the brand, and getting a bit closer to the sporting heroes."

A spokeswoman for the British Dietetic Association, said: "If you are not doing any activity and you are consuming these products, then it is likely you are going to put on weight."