Children need a well-balanced diet
Nine out of 10 mothers questioned in a British Heart Foundation (BHF) survey misunderstood the nutrition information on children's foods.
The BHF says mothers believe claims such as "a source of calcium, iron and six vitamins" mean a product is likely to be healthy.
A "mish mash" of different food labelling styles is fuelling confusion among shoppers, it added.
But manufacturers insisted their nutritional labelling was clear.
The research was carried out on 1454 parents aged between 16-64 years old with kids aged 15 or under through an online survey.
It found that 76% of mothers questioned believed that "wholegrain" means the product is likely to be healthy.
However, the BHF said that - for example - Nestle's Honey Shreddies, which claim to be wholegrain and to "keep your heart healthy and maintain a healthy body", contain more sugar [13.6g] than a ring doughnut [9.2g] in an average serving.
Kellogg's Coco Pops cereal and milk bars are labelled as "a source of calcium, iron and six vitamins" and 63% of mothers in the survey thought they were healthy.
The BHF said that for every 100g they were higher in saturated fat and sugar than the average chocolate cake.
The Natural Confectionery Company Jelly Snakes which are made by Cadbury's contain more calories gram for gram than black treacle, the BHF said.
Single labelling scheme
Almost three in five respondents believed that the phrase "no artificial flavourings, no artificial colourings" indicated a healthy treat.
The questionnaire found that 84% of them wanted a single, front-of-pack food labelling scheme.
Peter Hollins, BHF chief executive, 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 are a healthy choice.
"Regularly eating these types of foods could have serious implications for kids' future health."
A single unified labelling system for food is needed because it the "mish mash" of the different systems serves only to confuse shoppers, he added.
"It's time for food companies to stop making excuses, support one system and ensure shoppers are given 'at a glance' information about the foods they're giving their kids."
A spokesman for the Natural Confectionery Company said: "All we claim is that the sweets contain no artificial colours and flavours - which is true - so we're not sure why this should confuse anybody.
"All nutritional information is clearly labelled on the bag."
And a spokesman for Kellogg's responded: "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."
Julian Hunt, of the Food and Drink Federation, has complained that the BHF did not share its research with them: "The truth is that the food industry takes its responsibilities seriously.
"That's why our members are leading the world when it comes to ensuring that food recipes meet the demands of mums and their families - whether that's through the use of natural ingredients; reducing the amount of salt, fat or sugar used; or fortifying products with nutritionally-vital vitamins, minerals and micro-nutrients.
"The nutrition claims identified by BHF are not 'partial health claims' - they are approved under the EU Nutrition and Health Claims Regulation, which is setting a strict legal framework for all claims on food packs.
"To claim otherwise is being completely disingenuous - or shows that the BHF is deliberately trying to mislead both mums and journalists at what is a very busy time for all of us."