Author's response to reviews Title: Differential prevalence and associations of Overweight and Obesity by gender and population group among School Learners in South Africa Authors: Sarah Negash (sarah.negash@googlemail.com) Charles Agyemang (C.O.Agyemang@amc.uva.nl) Tandi Matsha (MatshaT@cput.ac.za) Nasheeta Peer (nasheeta.peer@mrc.ac.za) Rajiv Erasmus (rte@sun.ac.za) Andre Kengne (Andre.Kengne@mrc.ac.za) Version: 1 Date: 05 May 2017 Author’s response to reviews: Reviewer 1: Saad Siddiqui Dr Siddiqui has not raised any critic points. Reviewer 2: David Meyre Point 1: Dr Meyre argued that the importance of the study was limited and comments that numerous reports have been published which provide similar conclusions. We are not of the same opinion, as already presented in the background section of our manuscript, that childhood obesity in Sub-Saharan Africa is one of the biggest epidemics of our time. We believe that there can‟t be enough scientific evidence on this, especially while rates still are expected to rise. In our opinion it is rather good that our conclusions match those of previous reports, since it shows the actual situation. In fact, our study adds to compelling evidence on this health issue and promotes informed public health decision-making, not only in the Western Cape but also in other Sub- Saharan African regions. Point 2: Dr Meyre raised concern on the classifications of the ethnic groups and that we did not base them on genetic data. He suggests excluding mixed or unclear ethnicities from the analyses. Our classification is based on the officially recognised ethnic grouping in South Africa and is common to use in research. As mentioned in our article, the Coloured group is one of the five ethnic groups in South Africa. We explain in the study population section who the Coloured group comprises (Methods section, lines 10-12, page 4). We have to acknowledge that the