Dramatic and comprehensive action was required to stop the majority of us becoming obese by 2050, they said.
Everyone, from individual to the upper echelons of government, must become involved in the campaign against a condition which carries such great social and economic consequences, they said.
In 2002, those who were overweight or obese cost nearly £7bn in treatment and state benefits and in indirect costs such as loss of earnings and reduced productivity.
In 40 years time, that figure could reach nearly £46bn, as health services struggle to cope with the ill health such as diabetes, cancer and stroke which can be associated with excess weight.
"There is a danger that the moment to act radically and dramatically will be missed," said Sir David King, the government's chief scientific advisor and head of the Foresight Programme which drew up the report.
"It is a problem that is getting worse every year."
Obesity, the authors concluded, was an inevitable consequence of a society in which energy-dense, cheap foods, labour-saving devices, motorised transport and sedentary work were rife.
In this environment it was surprising that anyone was able to remain thin, Dr Susan Jebb of the Medical Research Council said, and so the notion of obesity simply being a product of personal over-indulgence had to be abandoned for good.
"The stress has been on the individual choosing a healthier lifestyle, but that simply isn't enough," she said.
From planning our towns to encourage more physical activity to placing more pressure on mothers to breast feed - believed to slow down infant weight gain - the report highlighted a range of policy options without making any concrete recommendations.
Industry was already working to put healthier products on the shelf, the report noted, while work was advanced in transforming the very make-up of food so it was digested more slowly and proved satisfying for longer.
But it was clear that government needed to involve itself, as on this occasion, the market was failing to do the job, Sir David said.
Public Health Minister Dawn Primarolo said the government would be holding further consultations to decide how to proceed.
She said it was too early to say whether the same "shock" approach seen in public health warnings against smoking would be adopted with obesity, or whether a tax on fatty foods, highlighted in the report but widely dismissed as unworkable, would be considered.
"The most important thing is there has to be public consent and understanding of the issues you're trying to challenge," she said.
"A mandate for change will be difficult because it has to be preceded by an understanding of the dangers of obesity."
The Royal College of Physicians said the report was "encouraging."
"The emphasis on cross-governmental initiatives is particularly welcome, as is the importance of addressing issues across society whilst avoiding blame," said its president, Professor Ian Gilmore.
The Food and Drink Federation said it understood its role in tackling the problem.
"Our industry is now widely recognised as leading the world when it comes to reformulating products; extending consumer choice; and introducing improved nutrition labelling," a spokesperson said.