The direct cost of obesity to the NHS is £0.5bn ($0.9bn; €0.7bn), while the indirect cost to the UK economy is at least £2bn, Liam Donaldson, England's chief medical officer, told a conference in London last week.
The obesity epidemic affects all the developed countries to different degrees, with the prevalence reaching more than 25% in some states in the United States and 20% in Australia. In the United Kingdom 22% of men and 24% of women are obese, he said.
Professor Donaldson was speaking at a conference organised by the Westminster Diet and Health Forum, a private organisation with parliamentary support that facilitates cross party debate on public policy issues.
Speakers attributed the growth in obesity to a variety of causes. Mike Kelly, director of research and information at the Health Development Agency, thought that the household appliances that made our lives easier bore some responsibility. People spent less energy in their daily activities because technical advances, such as central heating and modern appliances, eased their domestic work.
Ian Harvey, professor of epidemiology and public health at the University of East Anglia, Norwich, put more emphasis on a decrease in energy consumption at work, because most of our jobs now require much less physical effort.
Compared with 1970 fewer people work in manufacturing and more work in the public sector. He did not think that there had been a marked reduction in the amount of recreational physical activity that people took, but he added that accurate data were lacking on the trends over time of physical activity and calorie intake and of the ambient temperature at home and at the workplace.
As many as 8.5% of 6 year olds and 15% of 15 year olds are clinically obese, Deirdre Hutton, who co-chairs the European Food Safety Authority and chairs the National Consumer Council, told the conference.
Ms Hutton said that that in the future many children will die before their parents, because of diseases resulting from obesity. She said that myths such as "bad parenting" must be forgotten in a modern society where children have separate economic lives and that children must be educated to make informed choices about their health.
Philip James, chairman of the International Obesity Task Force, considers it a "miracle that anybody stays even moderately thin," when meals such as a cheeseburger, a large portion of fries, and a 450 ml soft drink can add up to 1166 kcal (4900 kJ). Advertising gave children confused messages about nutrition, he said, and can change their food preferences and buying behaviour.
He added that subsidies of agricultural products also played an important part, as children as well as adults were influenced by cheap prices.
Obesity is strongly linked to poverty, John Krebs, chairman of the Food Standards Agency, emphasised. Another problem was a lack of public information. Some people knew that high fat products were unhealthy but could not judge which products were high in fat and by how much. Another trick that food manufacturers played was to display macronutrients in grams on the labels, when the correct way would be to express their contribution in energy.
The obesity epidemic was a result of consumers' reluctance to change their habits and of producers' delays in reformulating food, said Jack Winkler, director of Food & Health Research, a campaigning organisation. He said that before things could improve consumers would have to admit to themselves that they were eating unhealthy diets and should change their habits.
The role of healthcare professionals was also felt to be important. Ian Campbell, a GP and chairman of the National Obesity Forum, said that the health professionals&8212;mainly GPs and primary care trusts&8212;had an important role. Other problems of obese people, who often live alone, are unemployed, and have related illnesses, had to be considered. He said tackling obesity was "not a cure, it's a management issue." His advice to GPs was to start treating their patients and not to "wait for the government to decide to act."