1. School of Public Health and Health Systems, Department of Applied Health Sciences, University of Waterloo, 200 University Ave Waterloo, ON N2L 3G1, Canada
2. Department of Nutritional Sciences, University of Toronto, 150 College St, Toronto, ON M5S 3E2, Canada
3. Department of Medical Ethics and Health Policy, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-4884, USA