The UK Government has been accused of "massively overreacting" by telling people not to eat crispy roast potatoes or browned toast despite there being no scientific proof of a link to cancer.
Experts on Sunday night said the Food Standards Agency's (FSA) new campaign, which warns people against cooking starchy foods at high temperatures for long periods, risks undermining support for "real" public health priorities like tackling obesity.
Launched on Monday, the official guidance aims to raise awareness of acrylamide, a chemical which forms in some foods when they are cooked in temperatures hotter than 120C.
It states that people can lower their risk of cancer by avoiding over-browning roast potatoes, chips, root vegetables as well as cereal-based foods.
But the advice is based on experiments on mice, rather than any studies showing that acrylamide causes cancer in people,
It is also not known whether even a diet high in browned foods such as well-done roast potatoes could expose a person to enough of the chemical to risk triggering the cancer.
According to the FSA, people should not longer "fluff" their potatoes before roasting them, as this increases the surface area and maximises the brown crispiness which for most people is the main point of eating them in this style.
The new FSA guidance also states people should roast potatoes and vegetables in a preheated oven for approximately 45 minutes, turning every 15 minutes to avoid over browning.
Using the slogan "go for gold", it also warned that people should set a timer for 25 minutes to ensure they catch them before they overcook.
Sir David Spiegelhalter, professor of the public understanding of risk at Cambridge University, said the campaign was inappropriate.
"I'm always ambivalent about public health campaigns that are not based on some pretty firm quantitative evidence," he said.
"Many things in life may increase risk, but it's the size of the risk that makes it important."
Acrylamide forms due to a chemical reaction between certain sugars and an amino acid in the food when fried, roasted, baked, grilled or toasted, rather than boiling, steaming or microwaving.
Chips and crisps are foods thought to contain the most amount of acrylamide because of their relatively greater surface area in proportion to weight.
The FSA is also instructing people not to keep bread in the toaster beyond a golden colour, as this also increases acrylamide.
Potatoes must also not be stored in the fridge as this too raises levels of the chemical when cooked.
Chris Snowdon, head of lifestyle economics at the Institute of Economic Affairs, said the FSA advice was an example of "mission creep" from the Government agency.
"They should be dealing with real safety issues like the handful of restaurants who are putting out genuinely dangerous food," he said.
"This sort of thing undermines public faith in scientific advice and terrifies people.
"People just don't know what to eat anymore because they're not being given clear advice."
Former Conservative health minister Edwina Currie told The Daily Telegraph: "I think people will be puzzled when they see this campaign, as the Government appears to have launched it before doing all the research."
The row broke as it emerged major manufacturers of potato products including McCain have been quietly working with the FSA to change cooking instructions on packs in an attempt to reduce acrylamide levels.
Chairman at the British Potato Council, David Burks, said people's acrylamide intake is influenced more by the variety of potato they eat than the way it is cooked.
"Most supermarket bought potatoes are low in acrylamide anyway, so changing how they are cooked will make little difference."
He added that the Government campaign would be more effective at reducing acrylamide intake if it focused on cutting back on crisps.
Edwina Currie questioned why acrylamide was being "prioritised" over "tangible issues".
"If they think this is a big issue but there are gaps in their knowledge, they should fund more research into it as an urgent priority," she said.
A spokesperson for the potato product manufacturer McCain said the company was complying with the Food Drink Europe "acrylamide toolbox".
Steve Wearne, director of policy at the FSA, said: "We are not saying people should worry about the occasional meal ... this is about managing risk over a lifetime.
"Anything you can do to reduce your exposure will reduce your lifetime risk.
"People might, for example, think 'I like my roast potatoes crispy', but they will just decide to have them less often."