The British Heart Foundation says parents are being "hoodwinked by manipulative food manufacturers" over their children's food.
The organisation says nine out of ten mums are being misled over foods which are high in fat, salt and sugar.
According to the BHF's survey, 76 of mums thought the phrase "source of calcium, iron and six vitamins" meant the food was likely to be healthy.
But Coco Pops use this line on their cereal and milk bars, which are higher in saturated fat and sugar than the average chocolate cake, says the BHF.
Mind you, I'd be surprised if anyone thought Coco Pops was the healthiest cereal on the market.
The BHF says food manufacturers manipulate parents by making distracting claims to market their products.
Peter Hollins, chief executive of the BHF, said: "Mums are having the wool pulled over their eyes by food manufacturers.
"Smoke and mirror tactics means that foods targeted at children and high in fat, salt and sugar are being disguised with partial health claims suggesting they're a healthy choice. Regularly eating these types of foods could have serious implications for kids' future health."
The BHF is calling for a simple labelling system to make it easier for parents to choose healthy foods for their children.
However, manufacturers say they already give parents all the information they need and are not making any false claims.
A spokesman for Kellogg's told the BBC: "A Kellogg's Coco Pops Cereal and Milk bar actually contains less than two teaspoons of sugar per bar and has half the calories (84) and far less fat than a chocolate bar.
"Parents understand this because we give them the information they need, through our front-of-pack labelling, to make similar comparisons."
What do you think? Does food need to be labelled more clearly?