A majority of Britons will be obese by 2050 if weight gain in the population continues at the current rate, a major Government report warned.
Scientists predict that in just over 40 years, 60% of men, 50% of women and a quarter of all children in the UK are likely to be clinically obese.
They would be in a weight category associated with serious health problems, such as type 2 diabetes and heart disease.
A mere 10% of men and 15% of women were expected to have a "healthy" weight in relation to their height.
The consequent impact of chronic health problems on society would cost Britain more than £45 billion a year.
Dealing with the problem will require a comprehensive long-term strategy on the scale of tackling climate change or smoking, it is claimed.
Even then, it could take 30 years or more to reverse the obesity trend.
The stark picture of Britain's future as a nation of overweight, inactive and unhealthy citizens is contained in the latest report from the Government's Foresight think-tank, which looks at future trends.
Almost 250 experts and scientists took part in the two-year investigation which culminated in the report "Tackling Obesities: Future Choices".
The key conclusion was that human biology is simply out of step with modern life in the 21st century, with its labour-saving devices, motorised transport, sedentary work and cheap high energy foods.
