The world's fattest nations are those with biggest bottom lines

FATTIES ARE taking over the globe. In every country in the developed world, waistlines are expanding. As prosperity grows, so do bottoms and, with some exceptions, a rough guide to national income can be obtained from the average dress or trouser size.

In Europe, obesity has increased by 10 to 40 per cent in most countries over the past decade and similar increases have been seen in the United States, Australia and the Far East. Figures presented at the International Congress on Obesity in Paris this week demonstrate that obesity is a global epidemic.

However, as the league table of the fattest and thinnest nations shows, the proportion of the population who are obese varies widely across the globe from the diminutive Chinese to the bulky Samoans. Obesity is not merely a reflection of the calories on the plate. It is influenced by genes, culture, physical activity and social attitudes.

In Britain, 15 per cent of men and 16.5 per cent of women are classified as obese, more than twice the proportion in 1980 when the equivalent figures were 6 per cent of men and 8 cent of women. More than one-third of women and almost half of men are considered overweight. Yet, as a nation, we are eating no more than we did two decades ago. The expanding British waistline is linked to the decline in physical activity. More cars and video recorders have meant more flab.

In a global context, the British come somewhere in the middle of the bulk rankings. The two main contributors to obesity are a sedentary lifestyle and a high fat diet and both are linked to prosperity.

Later this month, Britain's fatties will be able to try a new anti-obesity pill which works by compelling those who take it to stick to a low fat diet.

Xenical, which will be available only on prescription, works by blocking the absorption of fat so that it is excreted instead of ending up on the hips and thighs. Trials on 7,000 patients have shown that up to half achieved a 10 per cent weight loss maintained over two years.

The drug, whose chemical name is orlistat, is made by Roche and received its European licence on 30 July. It is to be launched in the UK on 21 September.

The drug is only licensed for the treatment of obese patients with a body mass index over 30. It has a different action from previous diet pills which worked by suppressing the appetite. If too much fat is eaten the amount remaining in the gut results in diarrhoea, providing a warning signal to the dieter.

Some experts have welcomed it as a novel approach to a growing public health problem. Dr Nick Finer, a specialist in obesity at the Luton and Dunstable hospital said: "It is a bit like having a personal minder who slaps you on the hand as you reach for the cream cakes."

Others are sceptical. Professor John Garrow, editor of the European Journal of Clinical Nutrition and former professor of human nutrition at St Bartholomew's hospital, London, said there was nothing drugs did that diets could not do. The priority was for the Government to put its authority behind the campaign to curb obesity. Tessa Jowell, public health minister, had dropped it as a target from the Healthier Nation programme.

Professor Garrow said: "Suggesting that obesity is controllable is seen as victim blaming. It is politically incorrect, although scientifically it is correct."

Although obesity is now a global epidemic, the bigger surprise is that more people are not affected. Animal studies have shown that rats given an unlimited quantity of palatable food will continue to put on weight until the food is restricted. Humans are no different, according to Professor Garrow.

"Human beings now live to 70 or 80 when they were designed to live to 20 or 30 from subsistence agriculture where scratching a living was pretty difficult. Now that we are living to a staggering age with food available 24 hours a day it is surprising that we are not all obese. The only reason people are not is that they are either young - because it takes time to gain weight - or that they have successfully exercised some control over their weight."

Estimates by the World Health Organisation's task force on obesity suggest that this is not mere fantasy. By 2005, there will be around 26 million obese adults in the US. On present trends, the entire population will be obese in 35 years unless Americans can be persuaded to curb their appetites.

Obesity is defined as a body mass index (BMI) over 30. BMI is a measure of thinness/fatness derived from a complex formula (weight in kilograms divided by height in metres squared).

A simpler approach, which gives a rough guide, is to take a waist measurement. If it is more than 102cm for a man (40in) or 88cm (35in) for a woman, their chances of suffering health problems associated with their weight rise sharply.