1. Department of Medical Ethics and Health Policy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;,
2. Department of Nutrition, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27516, USA;,
3. School of Public Health and Health Systems, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada;
4. Department of Nutrition Policy Research, National Institute of Public Health, 62100 Cuernavaca, Mexico;
5. Department of Physical Activity and Healthy Lifestyles, National Institute of Public Health, 62100 Cuernavaca, Mexico;