Children's diets are now so poor that more than two-thirds of them do not think fast food is a treat, British Heart Foundation research suggests.
A poll of 500 youngsters also found that 82% do not think of crisps as anything special. More than half do not consider sweets a treat.
The charity wants the government to ban the marketing of what it describes as junk food to children.
These messages were undermining what "normal" food was, it claimed.
"The infestation of artery-clogging foods that make up our children's everyday diets is putting their hearts and long-term health at risk," said BHF Director of Prevention and Care, Dr Mike Knapton.
Adverts for foods that are high in fat, sugar and salt are already banned during programmes which are aimed at the under-16 audience.
But the BHF wants all junk food advertisements banned before the 9pm watershed, which is when more children watch television.
It also wants food and drink firms to reduce their internet presence, and stop putting messages aimed at children on packaging. The Food and Drink Federation, which represents the industry, said UK firms were now widely recognised as "leading the world" in reformulating products; offering consumers healthier choices; and introducing improved nutrition labelling.
"When it comes to marketing, the UK already has some of the strictest rules in Europe - thanks to a combination of regulation and voluntary action covering TV and non-broadcast marketing," said Federation spokesman Julian Hunt. ( BBC )