Obesity: the West pays a hefty price

Insurance companies consider obesity to mean a weight 20 per cent greater than that considered healthy for one's height. To determine whether your weight is right for your height, find your body mass index (BMI) by dividing your weight in kilograms by the square of your height in metres. If the figure is between 19 and 25, you are normal. Between 25 and 30, you are overweight. Over 30, you are obese; over 40, you are very obese.

In the UK, 16 per cent of women and 13 per cent of men are technically obese, but figures are much higher in the US, where just under a third of the population is classified as obese. In the States, this is defined by a BMI of more than 27.8 for men and 27.3 for women.

While lack of physical exercise and consumption of high-calorie foods are the basic causes, could subtle cultural differences account for the higher US figure? "There is no evidence to suggest Americans are eating more calories, or that they are less active than we are, and the average BMI for people in the US and UK is about the same," says Tim Gill, director of the Post-Graduate Nutrition and Dietetic Centre at the Rowatt Institute in Aberdeen. "The main difference is that they are probably more devoted to the car and the TV, though we can't be far behind in the UK. The more extreme cases of obesity tend to be in the US - as well as the more extreme cases of thinness."

The average daily calorie requirement is 2,500 for men and 1,900 for women, but the US produces 3,700 each day for each individual. It is ironic, then, that the eventual effect of this over-abundance is to drain Western health services of cash. According to a 1994 report by the Office of Health Economics, it costs the UK pounds 30m to treat obesity alone and another pounds 165.5m through strokes, heart disease, diabetes, arthritis and cancers. In the US, obesity was estimated to have cost the health service nearly $70bn in 1990, and, as the size acceptance movement takes off over there, massive sums are currently being awarded in damages to victims of "sizeism". A 23-stone woman recently won $100,000 after being turned down for a nursing- home job - on the grounds that she could not bend over.