What do the sustainability indicators mean?
The sustainability indicators provide a rough indication what impacts one portion of a recipe has on three environmental areas: the use of land, the water consumption, and the emission of greenhouse gases. This information is only indicative as not just the ingredients but the actually used products can make a big difference depending on where and how the food has been produced. Using a comparison with reference values, a rough indication is given for each recipe if the environmental impacts are below or above the recommendation of the "Planetary Health Diet".
How are the values calculated?
For each of the three areas, the values of the impacts of the individual ingredients are summed up to calculate the values for the recipe. These absolute values are compared with the reference values for a portion in the "Planetary Health Diet" to get to the percentage values. A "medium" environmental impact is defined as a recipe that is within a bandwidth of 75%-125% of the reference values.
Where does the data for the sustainability indicators come from?
Different scientific studies are used to get to an indicative value for the environmental impacts of individual ingredients. These are aggregated based on the amounts in the recipe to get figures for one portion. Among the sources is data for CO2 emissions, water footprints, land use and the study of the EAT-Lancet commission.
How meaningful are the indicators?
The environmental impacts of a recipe depend on different factors. It is not only important what ingredients are used in a recipe but also where and how those products are produced. Hence, there can be considerable differences in the environmental impact of an individual ingredient depending on what product is bought. In addition, the scientific measurement of the impacts has its challenges itself. The indicators are therefore not well suited to give a precise picture of the exact impacts of an individual recipe, but they provide an indication which recipes tend to impact the environment more negatively than others.