Large numbers of South Africans receive social grants (public transfers) or remittances (private transfers), and yet one in four South Africans is food insecure. The purpose of this paper is to address two questions: do social grants and remittances improve food security and nutritional outcomes? If so, do these impacts differ between public and private transfers? Drawing on the National Income Dynamic Survey (NIDS), South Africa’s first nationally representative survey that follows more than 28,000 individuals over time, we found significant and positive impacts of the Older Person’s Grant and of remittances on the dietary diversity index, but not of the Child Support Grant. Moreover, we found no effect on food expenditure or on anthropometry (BMI) by the Older Person’s Grant, or remittances. However, some positive effects were found on children’s BMI from the Child Support Grant. We discuss why we observe different effects from different transfers, as well as giving several reasons why income transfers are failing to close the nutritional deficits in South Africa.