Healthy Diets at the Intersection of Human and Planetary Health.

Our diets are the greatest determinant of health, and what we eat is sustained and shaped by the food we produce. Food systems have increased production to feed the growing world population, which has also led to a dietary transition, with increases in energy and protein intakes, and only modest improvements in micronutrient density. Thus, undernutrition has decreased globally, while non-communicable diseases are dramatically increasing. Today, food systems are being threatened by global warming. Conversely, food systems are a major contributor to climate change and environmental degradation, generating one-quarter of all greenhouse gasses, using half of the world's habitable land, and are the largest source of water pollution. The greatest contributor to this environmental degradation is the production of animal-based foods, particularly meat. Food systems must ensure access to safe, nutritious, and sustainable foods (e.g., improving yields, reducing waste, and greenhouse gas emissions), decreasing animal-based food production, and increasing plant-based foods, which can positively impact our diets. On the "demand side", shifting our current diets from high animal-based foods to plant-based diets will decrease global mortality and disability. Our diet is at the intersection of our health and our planet's health and, thus, a major instrument to improve both.