Top medics warned today that McDonald's, Coca-Cola and Heineken's sonsorship of the Olympics sends the wrong message to a country with a soaring obesity problem.
Under the deal McDonald's will have the monopoly on brand-name foods at the Games.
Coca-Cola has the exclusive right to sell non-alcoholic drinks at Olympic venues while Heineken has been named the official beer.
But the Academy of Royal Medical Colleges is calling upon the British government to restrict advertising by the three firms.
Spokesman Terence Stephenson said: "It's very sad that an event that celebrates the very best of athletic achievements should be sponsored by companies contributing to the obesity problem and unhealthy habits."
About a quarter of Britons are obese and experts estimate that could rise to a half by 2030. Obesity and related illnesses cost the health system about £4 billion a year.
And Sir Ian Gilmore, special adviser to the Royal College of Physicians on alcohol, said he deeply regretted that the Olympics had appointed an official beer.
"It sends out completely the wrong messages to young people, making it seem as though no major event is complete without alcohol," he said.
London Olympic organisers have defended their decision to accept sponsorship from firms such as McDonald's.
"Sponsors provide a huge amount of the funding required to stage the games," a London 2012 spokesman said.