Taking "unhealthy" food out of school vending machines is "interfering and too simplistic", an expert in eating disorders has said.
The vending machine ban will come into force next September
There is no such thing as an "evil food", said Dr Dee Dawson, medical director of Rhodes Farm clinic.
She said fat was an important part of any diet, and that children needed to learn to make their own food choices.
But Education Secretary Ruth Kelly has said the "scandal" of junk food served in schools must end.
From next September, school vending machines will not be able to sell chocolate, crisps or fizzy drinks.
Processed sausages and burgers will also be banned from school meals from the next school year.
'No evil foods'
But Dr Dawson said children needed to learn to eat a balanced diet - including foods which are higher in fat.
She said chips and chocolate should not be taken off school menus entirely.
"Children need to be able to make proper choices.
"They are only in school for a few hours per day - they can get chocolate and crisps on their way home.
"Banning certain foods from vending machines is too simplistic."
"We should be educating parents and children about food and the value of exercise, and we are doing neither," she went on.
"There is no such thing as an 'evil food' - only an evil diet."
Labelling certain foods as "evil" would send out the wrong message and cause the assumption that to be healthy, a diet should contain as little fat as possible.
This can lead to a feeling of guilt which in some children may trigger eating disorders, she added.
Some children might take on board this message and think "I can eat a no-fat diet, achieve perfection and be better than everyone", Dr Dawson said.
'No bad thing'
But fat is an important part of everybody's diet, which is needed for cells, hair and skin and the functioning of the brain.
Children need to have a diet which is around 30% fat to be healthy, Dr Dawson said.
Consuming too little fat would lead to poor concentration and headaches.
For some children eating chocolate every day may be no bad thing if they are doing large amounts of exercise, Dr Dawson went on.
It is a question of enabling children to find what is appropriate for them.
Rhodes Farm is a residential clinic which provides therapy as well as school facilities for children with eating disorders.
Ms Kelly announced new nutritional standards for schools from next year after a report into the standard of school meals recommended children should have limited access to "unhealthy" foods and eat at least two portions of fruit and vegetables per day.