Thousands of head teachers are boycotting a promotion by Cadbury which offers schools sports gear in exchange for chocolate wrappers.
The scheme was launched last month, with the endorsement of a government minister and sports stars, but parents, head teachers, classroom teachers and a food watchdog have attacked it on health grounds.
Under the scheme, children would have to eat 2,730 chocolate bars to get a cricket set for their school.
A football net would require 5,440 wrappers.
Letters about the scheme have been sent to schools for them to pass on to parents, but thousands of head teachers are said to have decided not to do so.
John Dunford, the general secretary of the Secondary Heads Association said the scheme was contradictory and that parents and governors had told head teachers they were against it.
"Parents and governors are very concerned at promotions like this and at those for crisps because the products are very high in fat," he said.
Volleyball - 320 chocolate bars
Cricket set - 2,730 bars
Basketball - 170 bars
Volleyball posts - 5,440 bars, costing £2,000 with 1.25m calories
"Many heads will not circulate this material because they recognise the contradiction between educating children about healthy eating and promoting Cadbury's chocolates."
The food watchdog The Food Commission has also protested about the scheme.
It said if children ate all the promotional chocolate bars produced they would eat nearly two million kilos of fat and more than 36 billion calories.
The campaign - called Cadbury Get Active - was launched with the endorsement of sports minister Richard Caborn.
Later the government said he was not advocating that children eat more chocolate but was acknowledging that they were going to eat it anyway and could do so in the context of having a healthy life-style.
Under the scheme, up to £9m worth of sports equipment could be given to schools by Birmingham-based Cadbury.
The company insists the scheme will not specifically encourage children to eat more chocolate and will allow the wider community to help schools.
It says of the 22,000 or so schools eligible for the scheme, 4,000 have registered so far.
A spokesman for Cadbury Schweppes said: "This is a genuine attempt to tackle the problem of childhood inactivity.
"There is a very generous redemption - 15 pence in every pound spent on chocolate. The scheme was developed with the Youth Sports Trust - a very respected charity."