Table 1 Themes identified in the semi-structured interviews, with example quotes from the interviewees

Theme 1. Definition of sustainable diets

“I think the definition is complete and has all the different aspects in there. I’m just wondering whether these may be too theoretical and difficult to operationalise […] we must define what we mean by environmental impacts.” (I4: Environmental Footprints)

“I would say that’s a high-level definition and that’s fine, it sets the scene but now we are in a turning point in time where we actually need to be able to clarify what that actually looks like on the plate.” (I5: Food Profiling—Prioritization and Modelling)

Theme 2. Dietary and food systems necessary changes (the needs)

“It’s not possible to disseminate one universal dietary pattern on a whole region […] it is important to maintain the regional diet features in order to save cultural background or feeding behaviour.” (I16: Food Profiling—Prioritization and Modelling)

“[…] we really have to change to more plant-based diets […] also reductions in food loss and waste, can do quite a bit, but again they need to be seen in combination with dietary changes.” (I1: Environmental Footprints)

Theme 3. Considerations for the promotion of sustainable diets

“Integrating food more deeply into the education system could be very powerful.” (I7: Environmental Footprints)

Theme 4. Process-related/implementation challenges needed to be addressed to move forward (pathways)

“Being inclusive and trying to engage all the relevant actors in the food system is important.” (I8: Communication and Policies)

“There would be many people that don’t want to change their habits.” (I2: Environmental Footprints)