Jamie Oliver has compared unhealthy packed lunches with child abuse and says the British government should do more to improve school meals.
The celebrity chef was supported by TV presenter Kirstie Allsopp and British Olympian Victoria Pendleton outside Jamie's Fifteen restaurant in Shoreditch, London, to raise awareness about home cooking and healthy food.
Oliver criticised parents for giving children unhealthy packed lunches, saying: "I'd say some are close to child abuse so I think we're all talking about school dinners here, yes let's, let's do it and let's do it properly.
"Coming through the door every day are 60, 70 per cent packed lunches and they're not monitored and we've no right to monitor them.
"So it's really down to the head teacher and their confidence to be able to do what they can."
Oliver said he disagreed with Education Secretary Michael Gove about nutritional standards in secondary schools and added: "There's still a lot to be done and I guess from the big picture you want the most-hardest-to-reach kids, the most at risk to be looked after efficiently."
Oliver, who was speaking at a street party for his Food Revolution Day, said he was also working with businesses to combat unhealthy food at work.
"What are you feeding your staff, is it all bad choices? What's in the vending machine, is it all bad choices? Probably. Possibly."
The chef also said he had been working on a new season of his TV show Food Fight Club, which will be aired at the end of 2013, and another project about cooking on a tight budget.
Allsopp added that introducing children to healthy food was difficult but worthwhile.
"The first time I showed lentils to the children they just looked at me like I was insane," she said.
She said children's food was not a "mum issue" but a family issue, adding: "I know a great many men who cook really well, most of our top chefs are men, why doesn't that translate into the home?"
The TV presenter said she was working on a new show called Fill Your House for Free about freecycling instead of throwing items away.
Jamie's Food Revolution Day was celebrated with events in 75 countries.
The Shoreditch street party included food stalls, live music and workshops, and Oliver said other events were held as far afield as Chile, New Zealand and Sierra Leone.