Jamie Oliver's school meals campaign drove children to packed lunches, according to restaurateur and former School Food Trust (SFT) chair Prue Leith.
The Great British Menu judge said that Oliver's intentions were worthy of praise, because too many school meals contained unhealthy food, according to The Telegraph.
But Leith said his efforts had had the inadvertent consequence of school meal take-up plummeting as parents opted to send their children in with packed lunches instead, which were often even less healthy.
Speaking at the Hay Festival, she said: "We did a huge marketing campaign to get people back into buying school meals. Jamie's programmes had woken the Government up and they realised it was important.
"But his programmes did have the bad effect of making parents decide to withdraw their children from having school meals and we had to woo them back."
The celebrity chef's campaign began in 2005 when his documentary series Jamie's School Dinners was first aired on Channel 4.
It sparked national debate and earned Oliver an audience with Prime Minister Tony Blair, ultimately resulting in the Government at the time pledging £280m over three years to invest in kitchen facilities.
Leith, who was chair of the SFT between 2006 and 2010, also said she believed that nationally things were improving, with one in four state schools having a cookery club.
"We have succeeded in getting cookery into the national curriculum, which it now is. Every child in a state school can learn to cook - they can demand to be taught," she said. "But unfortunately a lot of parents don't think it is important."
Last July the SFT and Local Authority Caterers Association (LACA) reported that school meal take-up had increased for the third year in a row, with 44.1% of primary school children and 37.6% of secondary school students choosing school dinners.
The latest results are expected to be published next month.
By Janie Manzoori-Stamford
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