{The retraction follows the discovery of a mistake relating to the analysis and interpretation of the South African National Income Dynamics Study (SA-NIDS) data, especially that from Wave 4 presented in Figure 1. This error resulted from not incrementing age between Waves 1 and 4 and so not accounting for the normal increase with age in BMI among young people. Recalculation of the estimates shows that there is little change in mean BMI by age over the period between Waves 1 and 4 and thus no evidence of the large increase in the prevalence of overweight and obesity in young people shown in Figure 3 that is the main finding of the study. All authors accept responsibility and apologise for this error.}