England and Scotland have the highest levels of obesity outside North America, an international conference will be told this week.
More than one in five Britons are clinically obese, with more than 40 million Europeans now being affected, the conference will be told.
International experts will meet in Copenhagen to try to find solutions to Europe's "epidemic of obesity", as Denmark hopes to increase awareness of the issue in its six-month EU presidency.
Health ministers from across Europe will meet on Wednesday and Thursday at the European Conference on Obesity – the first time politicians across the continent have sat down together specifically to discuss the problem.
"Obesity is not only a direct health problem, it has a major effect on the economic output of a country as a whole," said Professor Jacob Seidell of the Free University of Amsterdam, who will be presenting a paper at the conference.
"It's an important contributor to cost of health care, as well as accounting for billions of euros in lost working days, early retirement and generally lower economic productivity."
England and Scotland top the table of European obesity, with Germany and Finland not far behind. Almost every country in the EU now has an obesity level of over 10 per cent, but according to the most recent figures from the International Obesity Task Force, clinical obesity in this country is now running at above 21 per cent.
Professor Seidell said: "We always thought the US would be the country to have the most absurd numbers of obese people, but Europe, and Britain in particular, is catching up rapidly."