This thesis investigated the association between diet-related environmental impact and health. Data were from 40,000 Dutch participants enrolled in the EPIC-NL cohort with available dietary data at baseline (1993-1997) and in 2015. Environmental impact of diet was calculated using greenhouse gas (GHG) emissions and land use and health was measured according to the Dutch dietary guidelines (RGV). Additionally, mortality risk of chronic diseases was examined. Diet-related environmental impact was not associated with mortality risk. In 2015, participants ate relatively more fish and chicken but comparable quantities of red and processed meat. This resulted in a healthier diet, but similar environmental impact. Scenarios in which 35 grams of meat per day was replaced by vegetables, fruit or fish were environmentally friendlier (< 10% less GHG emission) and healthier (< 19% lower mortality risk). Better adherence to the RGV was healthier and more sustainable. Modelled policy scenarios with a 15% or 30% higher meat price or 10% lower price for fruit and vegetables showed several billion Euros net benefits over a 30-year period. Important dietary patterns for environment and health were characterized by the ratio of plant-based to animal-based foods (patterns 1) or the amount of dairy consumed (patterns 2). Compared to the average diet in EPIC-NL, participants with a ‘plant-based’ diet had a favorable score for environmental impact and health, while participants with the ‘dairy-based’ pattern were slightly healthier but had a higher environmental impact. Health aspects have been central in current dietary guidelines. In order to integrate environmental impact, several adjustments are proposed for profit on both aspects.