1 Department of Nutrition, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Pediatrics, University of North Carolina, Chapel Hill, NC 27599, USA. Electronic address: rcoleman@unc.edu.
2 Department of Human Biology and Human Movement Sciences, Maastricht University, P.O. Box 616, NL 6200, MD, Maastricht, The Netherlands. Electronic address: matthijs.hesselink@maastrichtuniversity.nl.