Developing world's extra burden

By BBC News Online's Caroline Ryan in Boston

Experts are warning of a global epidemic of obesity which they say is no longer confined to Western, industrialised societies.

Biological anthropologists from the UK and US told the American Association for the Advancement of Science annual meeting in Boston that obesity was becoming a problem even in countries where some people were severely undernourished.

They said action to tackle obesity had to be targeted at each society individually.

And the scientists stressed that although genes did play a part in predisposing some people to obesity, this alone could not explain the trends now being recorded around the world.

Extra burden

Marquisa Lavelle, from the University of Rhode Island, said: "Obesity is no longer confined to Western, industrialised societies.

"In terms of developing countries, we tend to assume their problems are related to under-nutrition rather than over-nutrition.

"What we have discovered is that worldwide levels of obesity have increased to the point where many cultures and many societies have both under-nutrition and over-nutrition."

She added: "Given the association of obesity with chronic disease; with diabetes, with high risk factors for heart disease and cancers of various sorts, this puts a burden on the developing world which it can ill-afford."

Changing perceptions

Dr Stanley Ulijaszek, of the University of Oxford, UK, told BBC News Online that much of the problem was linked to how fatness was perceived in developing countries.

"There is very often not a negative perception of overweight and obesity. In Britain, 200 years ago being fat was associated with good health. Now, being fat is not seen very positively.

"But in somewhere like Samoa, fatness is seen as a very positive thing. Fatness is carrying your wealth on your body.

"Fatness is seen as a very positive thing until your relatives start suffering fatal heart attacks in their mid 40s."