The TV chef won the support of campaigners after raising concerns that England’s new academies were not obliged to sign up to tough food regulations introduced by the previous government.
Oliver called on parents to tell Education Secretary Michael Gove not to touch the rules, warning that a move away from them would be a disaster.
Mr Gove has insisted that academies should be given the freedom to decide what was best for their students.
Oliver said: “The bit of work that we did which is law was a good bit of work for any government.
“The standards are there to really keep everyone on their game. It’s not a large amount of paperwork, and what it’s for, which is essentially the future of our country, it’s really important.”
Oliver’s comments came as the Local Authority Catering Association (Laca) suggested its members were being asked to bring back some “unhealthy food”.
Laca chairman Lynda Mitchell said: “Our members are telling us that they have been approached by academies to relax the rules, and as providers to hundreds of thousands of schools we are concerned.
“They are being asked to put confectionery and other snacks back, especially at mid-morning. It is the return of the sausage roll to schools.”
More than two-fifths of primary school children and a third of secondary school pupils in England are now opting for school meals, according to the latest figures
Mr Gove has said that giving academies the choice to opt out of nutritional standards handed them the freedom to do what was best for their students.
In a letter to Oliver earlier, he wrote: “We have no reason to believe that academies will not provide healthy, balanced meals that meet the current nutritional standards.
“I trust the professionals to act in the best interests of their pupils.”