The UK's obesity timebomb

American-sized helpings of food are creating an obesity timebomb in Britain, doctors warn today.

Experts say jumbo hamburgers, cookies and muffins are becoming as common in the UK as the United States - where "portion distortion" has seen typical servings of food increase in size by up to seven times in two decades.

They fear giant helpings of calorie laden meals are exposing diners to numerous health risks, and today they accuse the food industry of luring consumers into buying outsized portions by offering "bargain" prices on multiple purchases and extra-large servings.

The warning follows mounting fears in America over portion sizes in shops, restaurants and homes.

Latest research shows that in the United States - taking into account size and weight - typical servings of fast foods, steaks, cakes and biscuits are up to seven times as large today as they were 21 years ago.

And it found that people will eat more than they need to when faced with larger servings.

The increase in portion sizes corresponds to soaring levels of obesity, with 30.5 per cent of the population classified as obese, compared with 14 per cent in 1984.

At a conference at the Royal College of Physicians today, experts are calling for an end to portion distortion - warning that similar trends are now apparent in Britain. Dr Jeffrey Prince, of London-based World Cancer Research Fund International, said: "Giant portion sizes have become the norm. The latest statistics indicate that Americans are "super-sizing" meals in their homes as well. The price they pay for these larger portions are obesity and chronic disease. A similar price will be paid by Britons if action is not taken sooner."

Doctors blame growing meal sizes on the "value marketing" principle, whereby supermarkets, restaurants and cinemas encourage people to buy "big eat" crisps, "king-size" chocolate bars, triple-pack sandwiches and "meal deals" containing crisps, sandwiches and sweetened drinks. One "meal deal", a popular lunch option for many office workers, can contain more than half the daily recommended calorie intake.

Professor Philip James, a Londonbased obesity expert and chairman of an international task force on obesity-said: "The extra food content costs the manufacturer very little but, to the consumer, it represents 'good value' and is highly enticing. When people are served more food they eat more food.

"The industry can help by not overpromoting the 'super-sizing' marketing model of the US."

Half of all adults in Britain are overweight, with one in five classified as obese. Obesity - which is linked to high blood pressure, heart disease, diabetes and cancer - costs the NHS around £3billion a year and accounts for 18 million sick days a year.

Professor James said: "This is a warning that needs to be heard. It is not just down to the Government or the industry - everyone must be involved in helping to change what and how we eat."

Studies have shown many diners fail to notice when they are given larger portions. In a recent experiment, when diners were given four differently sized portions of macaroni cheese on different days, fewer than half noticed the change. Those who took part in the study unwittingly consumed 30 per cent more calories on the days when they were served the largest portion.

Today the food industry defended its record, claiming larger portions gave consumers "more choice".

Martin Paterson, of the Food and Drink Federation, said: "Larger packs are not always consumed by one person or at one session, and parents can now often choose mini-products and multipacks."