Initial Catering is to trial Jamie Oliver-style menus at four schools in the London Borough of Merton.
The contract caterer, whose school meals were put under scrutiny by two national newspapers and the TV show This Morning last week, said it would remove shaped products and use fresher ingredients at the sites at an extra cost of 18p per meal.
Jackie Schneider, head of a Merton parents' group, said Initial was forced to act after the recent media coverage. She added: "We support the move and hope it will soon be rolled out to the rest of the borough."
An Initial spokeswoman said the changes were not in response to media coverage. "It's been in the pipeline for a while, and we chose Merton because it is a good place to start. At 18p per head there is a funding issue, so we can't do it across the whole borough."
She added that 100 more meals were eaten at two schools on the first day of the trial.