Downing Street has slapped down a newly-appointed minister who raised the prospect of imposing a sugar tax on c ompanies that sell unhealthy food.
Life sciences minister George Freeman said increased taxation should be looked at for firms selling sugary products that lead to "huge pressures" on state services.
But No 10 was quick to firmly rule out such a move, insisting other ways must be found to tackle the UK's obesity problems.
Asked if David Cameron was considering a sugar tax, the Prime Minister's official spokesman said: "No."
"Working with public health professionals, the industry on public health matters, including obesity, that is an important agenda," he added.
"However, as I hope I have been very clear in my first answer, I don't believe that the right approach here is to put sugar taxes on hard-working people to increase the weight and cost of their shopping baskets.
"So, we will continue with the approach that has been taken, which has been around working with the industry, working with public health bodies and the like."
Pressed on whether the minister had spoken out of turn, the spokesman said: "He does an excellent job as minister for life sciences. I'm happy to set out, when it comes to taxation, the positions of the First and Second Lords of the Treasury (the PM and Chancellor)."
Mr Freeman warned companies that "insist on selling those products" that the Government would tax them while giving a talk at the Hay Festival, according to the Telegraph.
"I don't think heavy-handed legislation is the way to go," he reportedly said.
"But I think that where there is a commercial product which confers costs on all of us as a society, as in sugar, and where we can clearly show that the use of that leads to huge pressures on social costs, then we could be looking at recouping some of that through taxation.
"Companies should know that if you insist on selling those products, we will tax them."
His comments came as the Food Research Collaboration (FRC) said the Government should stop living in a "fantasy world" and consider taxing unhealthy products.
The FRC said countries including Finland, France and Mexico already have such measures in place and have been found to reduce the amount of unhealthy products purchased.
With nearly two-thirds (64%) of adults classed as overweight or obese in England last year and the associated health problems costing the NHS more than £5 billion every year, its report said the need for a change in many people's diets was "beyond doubt".
Unhealthy products with low nutritional value should be made more expensive, with the extra revenue that could be raised by taxing food and drinks with high levels of fat, sugar and salt put into fighting obesity, they suggest.
The FRC - a collaboration of bodies across the UK - is chaired by Professor Tim Lang of the Centre for Food Policy at City University London.
He said: "Governments have for too long been in a fantasy world where cheap food is celebrated as a good thing, without including the externalised costs in the form of ill-health, rising healthcare costs and lost human potential.
"Food taxes may make politicians nervous but must be explored, not least because everybody pays in the end through NHS costs or lost quality of life."
The report said recent academic research focusing on the price of unhealthy foods and cost of diets also found the healthiest diets cost double the price of the least healthy ones.
Furthermore, the price of unhealthy foods has been shown to be decreasing over time while the gap between the price of healthy and unhealthy foods is widening, they said.
Price promotions are also becoming more common at supermarkets, with one piece of research finding that items bought in such promotions account for 37% of calories, 34% of sugar and 39% of saturated fats consumed.
They also pointed to evidence that shows lower socio-economic groups are more likely to buy less healthy foods and beverages, while higher socio-economic groups purchase healthier options.
Dr Laura Cornelsen, a research fellow at London School of Hygiene and Tropical Medicine who was invited by the FRC to co-write the paper, said: "Measures such as taxes should be more seriously considered, as consumers do take prices into account when buying food. However, it's important not to have illusions that a tax alone will magically solve our nutrition-related health problems.
"While not a silver bullet, a well-designed tax has potential for positive health impact if implemented in combination with other strategies and policies that aim to improve our food environment, tackle obesity and nutrition-related disease."
Tesco has become the first retailer to commit to a major sugar reduction programme, with a 5% year-on-year open-ended reduction in sugar across its entire sugary soft drinks range.
The supermarket giant has agreed to the removal of all added sugar from the Kids category from September and will begin to move towards removing all added sugar from squash among other moves, which have been welcomed by campaign group Action On Sugar.