It is well known that healthy diets are important for human health. But what about the health of our planet? According to many, our diet is one of the main factors that affect our living environment. Food production and processing lead to greenhouse gas emissions, such as CO2 and methane, soil erosion, increasing water use and a reduction in biodiversity. These factors, in turn, affect human (and animal) health. After all, we live in one joint ecosystem: changes in nature have consequences for humans and vice versa. For example, the increase in greenhouse gases and warming of the earth leads in already marginalised areas to a reduced harvest, increase in plant diseases, and post-harvest losses due to spoilage, but possibly also to an intrinsic reduction of the nutrient density of the crops. A healthy and sustainable diet makes a major contribution to both public and planetary health and can be seen as important, and even necessary, input to improve both.