Global adherence to a healthy and sustainable diet and potential reduction in premature death

The Planetary Health Diet (PHD), also known as the EAT-Lancet reference diet, was developed to optimize global dietary quality while keeping the environmental impacts of food production within sustainable planetary boundaries. We calculated current national and global adherence to the PHD using the Planetary Health Dietary Index (PHDI). In addition, we used data on diet and mortality from three large US cohorts (n = 206,404 men and women, 54,536 deaths) to estimate the total and cause-specific mortality among adults 20 y of age and older that could be prevented by shifting from current diets to the reference PHD. The PHDI varied substantially across countries, although adherence was universally far from optimal (mean PHDI = 85 out of 140). By improving the global PHDI to 120, approximately 15 million deaths (27% of total deaths) could be prevented annually. Estimates of preventable deaths due to this shift ranged from 2.5 million for cardiovascular diseases to 0.7 million for neurodegenerative diseases. Our analysis suggests that adopting healthy and sustainable diets would have major direct health benefits by reducing mortality due to multiple diseases and could contribute substantially to achieving the United Nations Sustainable Development Goals. These numbers of preventable deaths are based on evidence that human biology is similar across racial and ethnic groups, but the exact numerical estimates should be interpreted with caution because some assumptions used for the calculations build on limited data. Refinement of these estimates will be possible when additional regional data on diet and mortality become available.