Tristan Gorgens, from the policy and strategy unit in the Western Cape government, said research showed that food security had effects on schoolchildren and society, including nutrition, learning ability and crime levels.
"Most poor families are spending up to 40% of their income on food, and most of the energy they are getting is from cheap foods that are high carbohydrates," Gorgens said.
About 12 million children - more than 75% of all pupils - in more than 20,000 public schools are fed daily through the government's National School Nutrition Programme.
But feeding a child was more complicated, according to Stephen Devereux from the Centre of Excellence in Food Security.
"School feeding was initially promoted as an anti-hunger programme. But studies showed it was difficult to reverse the impact of malnutrition, including stunting, in children affected in the first two years after birth," said Devereux.
• This article was originally published in The Times.
