More government money is needed to make sure TV chef Jamie Oliver's "crusade" to improve England's school dinners does raise standards, caterers say.
Even Jamie Oliver struggled to get children to like meals
Otherwise, parents will face price rises to reflect the higher cost of using fresh ingredients, the Local Authority Caterers Association said.
Mr Oliver has replaced all processed foods at Kidbrooke School in Greenwich, London, with freshly cooked meals.
He has said government funding should rise from 37p a day per pupil to 50p.
Mr Oliver has described much of the processed food served to children as nutritionless "rubbish".
But LACA chairman Neil Porter said caterers were under pressures of time and limited budgets.
Some schools had cut lunchtimes to half an hour and EU law prevented guidelines compelling schools to use only local, fresh ingredients.
Mr Oliver's efforts at Kidbrooke - to be featured in the Channel 4 series Jamie's School Dinners - were not popular at first with its pupils, with canteen use actually declining after his arrival.
However, the likes of fish pie, lemon roasted herb chicken and chilli beef fajitas eventually saw children returning to school dinners.
Mr Oliver recently met Education Secretary Ruth Kelly to discuss catering standards.
She has promised that guidelines on the nutritional value of processed foods such as beef burgers and sausages will be introduced into schools in England from September.
Parents and the food industry are also to be consulted on standards.
Mr Porter said: "Perhaps with someone of Jamie Oliver's profile and voice leading the crusade, at last the government will act.
"We hope he will combine his new found knowledge with his celebrity influence to persuade the government that it needs to significantly increase its promised investment of just £1.1m to improve school meals."
Greenwich has decided to implement similar healthy eating initiatives at all its schools.
Mr Porter said: "It is one thing developing and fine tuning a brand new school menu at one school over a period of time with the full involvement of an influential celebrity chef that ensures the commitment of council leaders, governors, heads, teachers and parents".
But most would have "no celebrity chef presence in the kitchen, no TV filming and no hype, just a radically different menu change practically overnight".
Kitchen staff required more training in dealing with fresh ingredients within budget constraints, Mr Porter said.
The school dinners debate comes amid rising rates of childhood obesity.
Last week, Kidbrooke's head teacher, Trisha Jaffe, told the BBC News website: "The fact that Jamie is a gourmet chef doesn't interest the pupils.
"They are interested in what they like. You have to get them used to a different kind of eating."