Excerpts of a government-commissioned report have revealed half of Britons could be obese within 25 years.
The Foresight study, expected to be released in full this week, reportedly claims that rising obesity levels will cost the country £45 billion a year by 2050 through increased care requirements and missed working hours.
Last week the government's comprehensive spending review allocated potential funding to help tackling obesity, and health secretary Alan Johnson admits that the UK "cannot afford not to act".
"We are facing a potential crisis on the scale of climate change and it is in everybody's interest to turn things round," he said.
"We will succeed only if the problem is recognised, owned and addressed at every level in every part of society."
But he added that it would take a "cultural and societal shift" to address the deep-rooted problems of inactivity and increased propensity towards junk food.
Mr Johnson is expected to unveil plans to extend bans on television adverts for unhealthy food to programmes watched by teenagers as well as children.
He continued: "There is no single solution to tackle obesity and it cannot be tackled by government action alone.
"We will only succeed if the problem is recognised, owned and addressed at every level and every part of society."
Foresight's research, compiled over the last two years, will reportedly show that by 2022 nine in ten men will be overweight, while 70 per cent of women will be overweight within 20 years.