The Prince of Wales has appeared to criticise fast food chain McDonald's at the launch of a public health campaign in the United Arab Emirates (UAE).
Prince Charles trying a local dish during his tour
During a tour of a diabetes centre in Abu Dhabi, he told a nutritionist that banning the restaurants was "key".
McDonald's said it was "disappointed", adding that other royals "have probably got a more up-to-date picture of us".
Prince Charles is a keen advocate of organic produce and has his own range of foods.
His remarks were made after he and the Duchess of Cornwall were told about new initiatives to improve the nation's diet and fitness levels.
The UAE has the second highest prevalence of diabetes in the world.
Prince Charles asked nutritionist Nadine Tayara: "Have you got anywhere with McDonald's, have you tried getting it banned? That's the key."
A McDonald's spokesman suggested Charles was unaware of the company's efforts, which included improved labelling and supporting sustainable agriculture.
The British Medical Association said it would not comment specifically on Charles's remark.
But it has raised general concerns about so-called "junk food" and its advertising.
In a statement, a Clarence House spokesman said the Prince has "for a long time advocated the importance of a balanced diet, especially for children."
Earlier this month, he hosted a reception at Clarence House in London for cooks and head teachers to stress the importance of giving pupils healthy meals.
Jamie Oliver, celebrity chef and national campaigner for improved school dinners, was among the guests.
In 1986, the Prince set up a farm on his Highgrove Estate that does not use artificial pesticides or fertilisers.
Earlier in their tour of the Gulf states, the royal couple visited Kuwait's largest mosque and a new museum of Islamic art in Qatar.
The trip is aimed at "reinforcing Britain's friendship with key allies".