A teachers' union has condemned what it sees as the increasing and damaging commercialisation and sexualisation of childhood.
Pester power can lead to poor diets, the NUT says
A charter from the National Union of Teachers calls for a legal ban on advertising in schools and curbs on who can produce educational materials.
General Secretary Steve Sinnott said "irresponsible" firms made it hard for teachers to promote healthy lifestyles.
Some of the companies complained about have denied doing anything wrong.
In its 12-point charter, Growing Up in a Material World, the NUT said children were deliberately targeted by advertising, sponsorship and "viral marketing" campaigns that could damage their physical and mental well-being.
The charter was published at the start of the union's annual conference in Harrogate.
Mr Sinnott said teachers felt constrained in trying to raise the issue, because parents were busy collecting vouchers from Cadbury chocolates or Walkers Crisps literally under the banner of books for schools.
"Why did supermarkets produce vouchers?
"It's not to ensure that our youngsters are IT literate it's to raise the profile of supermarkets.
"Look at the school gate," he said. "There's a big banner. The school looks as if it is identifying itself with Sainsbury's."
Mr Sinnott told journalists that one of the most disturbing aspects of the whole issue was the inappropriate sexualisation of pre-pubescent youngsters.
Examples included Tesco selling a pole-dancing kit in its online toys section and Asda selling black and pink lace lingerie for children.
Asda said it had sold these about five years ago, but they had been withdrawn from sale.
"We take our duties as a responsible retailer very seriously indeed," a spokesman said.
A Tesco spokesman also refuted the allegations, saying the pole-dancing kit was clearly aimed at adults who wanted to improve their fitness and was not sexually orientated.
The latter claim was ridiculed by NUT officials.
Sainsbury's was not available for comment, but a statement on its website said its Active Kids scheme had raised £34 million worth of equipment and experiences for children since 2005.
The NUT's charter seeks government action, including legislation against in-school marketing.
Mr Sinnott said the union had not yet raised the issue with ministers but would be doing so.
He wanted teachers to start a debate within their schools.
But he also called on parents to recognise that sophisticated marketing techniques were being used on their children to generate "pester power".
Research for the National Consumer Council had shown that children from poorer backgrounds were the most vulnerable, he said.
They were most aware of branding but their families were least likely to be able to afford "cool" products - so the children were vulnerable to being stigmatised and bullied.
"This is an important issue for us all. We are letting our youngsters down at the moment," Mr Sinnott added.