Plans for a tax on fatty foods such as cakes and biscuits are being considered by government advisers.
Burgers are among the foods likely to be hit by a 'fat tax'
The Prime Minister's Strategy Unit is considering increasing duties on some food and having a sports drive to fight obesity, according to the Times.
The newspaper claims a document urges a fatty food tax as a "signal to society" because the number of obese British people has risen sharply in 20 years.
A Downing Street spokesman said the government had no plans for such a tax.
He said: "It is no secret that the government is looking at the problem of obesity.
Dairy products: fresh butter, cheddar cheese, full fat milk
Fast food: Cheeseburger, takeaway pizza, potato wedges
Sweets: Milk chocolate bar, Danish pastry, butter toffee popcorn
Source: strategy unit paper according to the Times
"But no proposals of this kind have been put to the prime minister."
The spokesman said that there was agreement both in and out of government that it would not be a workable system.
However, he confirmed the story came from a minor discussion document by their strategy unit.
The Times says the strategy unit's paper, titled Personal Responsibility and Changing Behaviour, points out that NHS spending on obesity-related disease has risen.
"The main drivers - poor diet and a sedentary lifestyle - are largely outside the direct influence of the NHS," it says.
It suggests a number of policies such as a national sports drive along the lines of the successful Active Australia strategy, and lifestyle lessons in schools.
A new tax or the extension of VAT is proposed for some dairy products, fast food and sweets.
"This would be a signal to producers as well as consumers and serve more broadly as a signal to society that nutritional content in food is important," says the document.
Last year doctors at the British Medical Association (BMA) debated a proposal to impose the full 17.5% VAT rate on a wider range of high-fat foods such as biscuits, cakes and processed meals.
The full 17.5% rate is already charged on some foods including fizzy drinks, crisps and heated burgers.
The British Medical Journal recently claimed a 'fat tax' could help prevent 1,000 premature deaths from heart disease every year in the UK.
Martin Paterson, of the Food and Drink Federation, said a fat tax would hit lower income families who already spend a higher proportion of their income on food and drink.
He said: "Consumers will rightly feel patronised by "top-down" messages based on the idea that they can't think for themselves and need to be taxed into weight-loss.
"The idea that any particular food is bad for you is out of date and simplistic. A balanced diet can include snacks and treats - moderation is the key."
Tim Yeo, Shadow Shadow Health and Education Secretary, said: "The government's approach to tackle the problems of obesity, like their approach to all public health issues, has been haphazard and has lacked coherence.
"The Department of Health has announced a consultation paper on public health, the Treasury has commissioned Derek Wanless to look into matters, including public health, whilst Number 10's Strategy Unit have been working on yet another tax - the fat tax."