NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands. Department of Nutrition and Movement Sciences, Maastricht University Medical Center, P.O. Box 616, 6200 MD, Maastricht, the Netherlands. Department of Radiology, Maastricht University Medical Center, Maastricht, the Netherlands. Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA. Department of Physiology, Radbound University Nijmegen Medical Center, Nijmegen, the Netherlands. Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Düsseldorf, Germany. Departments of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA. NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands. p.schrauwen@maastrichtuniversity.nl. Department of Nutrition and Movement Sciences, Maastricht University Medical Center, P.O. Box 616, 6200 MD, Maastricht, the Netherlands. p.schrauwen@maastrichtuniversity.nl.