Environmental impact assessment of dietary scenarios: a review on methods

Summary

Dietary patterns have manifold impacts on human health and the environment. Impact assessments are employed to compare impacts of single food items or of diets as a whole, either in their current state or for theoretical scenarios.
However, conclusions from impact assessments focusing on theoretical scenarios are diverse, and occasionally even contradicting. The role of animals and types of production are key aspects of these discussions. Therefore, the aim of this study is to analyse the methodological choices that cause these differing conclusions. We find that consideration of food-system-wide consequences of dietary change in the impact assessment, differentiation between land use categories, and production units are central for determining which theoretical dietary patterns are more or less sustainable and for understanding the role of animal source food.