He said 70 per cent of packed lunches in Britain were "disgraceful" and called for them to be banned.
Oliver said head teachers were too frightened to tell parents what they should be giving their child to bring to school.
The celebrity chef criticises parents in his new TV series, Jamie's Return To School Dinners, the follow-up to his successful Channel 4 programmes on improving school meals.
In the show, Oliver says: "Now is the time to say `if you're giving your young children fizzy drinks, you're an a*******, you're a t******.
"If you give them bags of crisps, you're an idiot. If parents truly care, they've got to take control."
Oliver said after the screening of the new programme: "I have seen kids of the ages of four or five open their lunch box and inside is a cold, half-eaten McDonald's, multiple packets of crisps and a can of Red Bull."
He added: "Packed lunches are a problem. Most of them aren't appropriate."
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Ace Riley, manchester (08/09/2006 at 12:11)