Some of the world's biggest junk food companies are being paid millions of pounds of taxpayers' money to develop healthier products.
Firms which produce some of the biggest brands are receiving grants that will help them meet pledges to cut salt and fat in their food, from the department of Vince Cable, the Business Secretary.
Companies that have accepted the money include the makers of Walkers' Crisps, Wrigley's chewing gum, Walls ice cream, Pot Noodle and Mr Kipling's cakes.
The money is being spent on research projects with university academics to create new technologies and ingredients for the companies.
Critics have now questioned whether public funds should be used to help these companies improve the nutritional value of their food.
The firms, many of which have turnovers of billions of pounds, already benefit from the substantial tax relief available to manufacturers carrying out research and development.
There is also concern that Mr Cable's department is attempting to "pick winners" by choosing how to invest in the food industry.
At least £2.9 million of public money from government research councils has been used to fund projects led by manufacturers of snacks and convenience foods to carry out research on healthier products.
These are being conducted alongside academic researchers at universities, but each project is led by the manufacturer and is intended to produce products or techniques they can exploit for a "commercial return".
In some cases the companies have deemed the work so commercially important that they have refused to release further details despite receiving taxpayers money to carry out the research.
The projects include:
* A project code-named "Oliver" by PepsiCo, who produce Walkers Crisps, to "unlock new technologies" to develop healthier snacks that received £246,669 of public money;
* PepsiCo also received funding to develop salt reduction technologies drawing on research from Birmingham University and to develop a new "starch conversion processes" to create baked snacks;
* American chewing gum manufacturer Wm Wrigley Jr is leading a project with £198,500 of public funding aimed changing the bacteria in the mouth to improve dental health;
* Premier Foods was awarded £185,000 to develop foams and emulsions to replace fat in foods;
* A £256,240 research grant was awarded to Unilever, who own brands including Walls, Magnum, Pot Noodle and Ben & Jerries, to create new "functional foods" containing phytonutrients – compounds from plants thought to promote human health.;
* Unilever also received funding to look at the effect of compounds from plants on blood vessels and the ageing process;
* GlaxoSmithKline, which owns Lucozade and Ribena, was given £189,340 for research on the health benefits of polyphenols from fruit;
* Macphie of Glenbervie a baking firm based in Scotland, was given £244,021 to help develop a new process to bake healthier foods using ultrasound;
* Bernard Matthews, the turkey farming giant criticised by chef Jamie Oliver over its processed meat products including Turkey Twizzlers, also received £223,060 for a project to develop new tests on farms for food poisoning bacteria.
All of the companies put in their own funding into the projects, but the Department for Business, Innovation and Skills helped support the research through its research funding councils and the Technology Strategy Board.
It comes after many of the firms signed a Department of Health-led deal to reduce the calories and levels of salt in their products.
Ministers have faced criticism from health campaigners for ruling out regulations on junk food, and were accused of giving into lobbying from food companies by allowing them to voluntarily sign up to pledges on healthy food.
Stephen Dorrell, chairman of the all-party Commons Health Committee and a former Conservative health secretary, said: "Multinational companies who sell products that are involved the issue of obesity have to take responsibility for that.
"Part of that means they have to look at how the nutritional values and health implications of those products can be addressed. The point is that they must do that work and should not be bribed by the taxpayer.
"In the present public expenditure environment, the burden of proof has to be on anyone who wants to make the case for companies like Unilever [owner of Walls and Pot Noodle] to have public money to do research on how to make its own products more nutritious.
"This is at the core of what they do and they should be working this out for themselves."
A spokesman for the Technology Strategy Board said funding large companies to conduct research and development could help to encourage other firms to follow their example and benefit the UK economy.
She added: "Large companies sometimes find it challenging to engage with innovative R&D which can be higher risk and more expensive than routine product development programmes they are more comfortable with.
"It is part of our role to share this risk and enable innovation to happen."
Defra has also in the past helped to fund projects involving sweet manufacturers Mars, Nestle and Cadbury.
Unilever, Mars, PepsiCo, Nestle and Kraft, which owns Cadbury, all have large multi-million pound research and development facilities where they develop products and they receive tax relief for any money they spend on research and development.
These firms are among 170 organisations from the food and drink industry who signed the Department of Health's Public Health Responsibility Deal to reduce obesity by meeting a series of voluntary pledges including cutting salt and calories in products.
The research funding was agreed separately to the Responsibility Deal and will also help fund research at British universities, but anti-junk food campaigners insisted multinational food companies should be willing to pay for such work themselves if they benefit.
Malcolm Clark, coordinator for the Children's Food Campaign, said: "These companies are among the worst offenders for producing unhealthy food, but they have the budgets and resources to do this work themselves.
"The government and the industry has been promoting the Responsibility Deal as a voluntary initiative that puts industry in a good light.
"I think it places an unfair spin if in fact government funds are being used to help these companies carry out the research and development they need to do to make their products healthier."
A spokesman for Premier Foods insisted the results of their research would be made available to all UK food companies and insisted there was no link between the research and the commitments the company made under the Responsibilty Deal.
He said: "The research is 'pre-competitive' and as such the results will be available to all UK food companies. The company's responsibility deal commitments will be met independently of the outcome of this research."
A spokesman for PepsiCo said the funding represented a fraction of their £40 million annual spend on research and development. She added: "Many of the world's most-talented scientists are based in the UK and schemes like this help to keep the UK at the forefront of global research."
A spokesman for Unilever added: "We have a proud heritage of working with others to tackle the highest priority social and environmental challenges, including those in the public health arena.
"Through the Technology Strategy Board, we are working as part of a scientific consortium comprising business, academia and Government, to research projects exploring challenging areas of public health such as reducing obesity and diabetes.
"By working in partnership in this way and co-funding important research, we can have a wide-reaching, positive impact on the health of the nation."