The third Global Nutrition Report released this week found that South African children were worse off than their counterparts in many poorer countries, including Haiti, Senegal, Thailand, Libya and Mauritania.
The report calls for an increase in political will to end malnutrition.
South Africa placed 70 out of 132 countries for stunted growth rates.
About 23.9% of children under five are stunted, mainly due to a lack of nutrition.
Mervyn Abrahams, director of Pietermaritzburg Agency for Community Social Action, said stunting was getting worse in South Africa, despite it being one of the richer countries on the continent, because the “conditions where stunting arises have worsened” over the past two years.
He said food inflation, the economy and the drought made it harder to eat healthily.
“South African households cannot absorb the food price increases due to high unemployment and low wages.”
Food was also one of the last things households spent money on, meeting debt obligations first, then paying rent and transport before eating, he said.
“I hear of a greater proportion of children coming to school hungry more often than not.”
Malnutrition is an economic problem, with the report warning that 11% of the GDP was lost every year in Africa and Asia due to the consequences of it.
“It makes economic sense to fix malnutrition with a $16 (about R245) return for every $1 spent,” said the report.
“If South Africa wants to improve the economy, it must make sure children have enough to eat,” he said.