Furthermore, while they account for diet in their covariate analysis, it's not very detailed or granuar so it doesn't account for other sources of sugar that these kids might be having (the authors acknowledge this). Based on this study it's hard to conclusively say whether it's the sugar that negatively impacts cognition or other ingredients, or vice versa whether kids with poor executive function prefer sweet drinks. Probably still a good idea to limit refined sugar intake for your own kids though.