Tax rises on fatty foods have been urged by doctors in order to curb growing obesity levels.
The price of cakes would increase
The British Medical Association (BMA) is discussing a proposal to charge 17.5% VAT on high-fat foods such as biscuits, cakes and processed meals.
Most food is currently exempt from VAT and extending the tax would earn the Treasury millions of pounds.
Obesity-related problems are estimated to cost the NHS at least £500m a year.
Last week it emerged the Labour Party was considering introducing health contracts to encourage overweight people and smokers to have healthier lifestyles.
British diet 'harmful'
But a super tax on fatty foods would be perceived as a regressive tax because people on lower incomes tend to eat proportionally larger quantities of cheap, high-fat food.
A public health doctors' conference this week will discuss a motion by Dr Martin Breach which says: "Given the epidemic of obesity related disease in the UK, this conference strongly supports the concept of a tax on saturated fats, in effect a VAT on fat."
Dr Breach, a GP in Haydock, Merseyside, is on the BMA public health committee and is the association's spokesperson on this issue.
"The UK is facing an epidemic of obesity and obesity-related disorders," he told BBC Radio 4's Today programme.
"A fifth of men are obese and very nearly a quarter of women in the UK are obese and this figure is expected to rise further."
Obesity is closely linked to a range of health problems such as diabetes, heart disease and high blood pressure and degenerative problems such as arthritis.
You are harming the people who need the help - and that is often low-income families
Anthony Worral Thompson
While the BMA is trying to stimulate debate on the issue, Dr Breach said the government has responsibility for deciding which foods could be taxed.
"Education is absolutely essential and getting kids started on the right diet early is going to lay the right sort of foundation, but the British diet is unfortunately harming our population and it is having very severe and very widespread health effects," Dr Breach said.
The UK is rated the eighth most obese nation in the world, with one in four Britons likely to be obese by 2010.
In 2000, dietary expert Dr Tom Marshall, of the University of Birmingham, estimated such a tax could prevent between 900 and 1,000 premature deaths a year in the UK.
Chef urges education, not taxation
Celebrity chef Anthony Worral Thompson said education was a better option than taxation to improve the eating habits of Britons.
"You are harming the people who need the help - and that is often low-income families who actually survive on this types of food," he told Today.
"Surely it's not about taxation, it's about education, getting into schools at an early age and dictating in some ways the children's diet.
"If you feed them junk food, they're going to be used to junk food, they're going to enjoy junk food. If you feed them from an early age good food, healthy food, lot of vegetables, they're going to get used to that and enjoy that."
Extending VAT would bring the UK into line with most of the European Union.
All other EU countries except Ireland impose various degrees of VAT on food.
In the UK hot takeaways like hamburgers are already subject to VAT.