Open Access

Nutrition is responsible for about 30% of global natural resource use. In order to limit the negative impact the nutritional sector has on the environment and on society, the consumption and processing of foodstuffs with assumed low negative impact is an important topic in the effort of sustainable development. In professional kitchens, clearly defined indicators assessing the impact of business activities are needed in this effort. The research and development in the NAHGAST project provides groundwork that could be of important assistance in this effort. Two versions of an assessment tool, with indicators of different complexity (NAHGAST Meal-Basic and NAHGAST Meal-Pro), were developed that can be used by kitchen professionals to determine the sustainability performance of their products - the offered meal. An informed selection of indicators, and a discussion of what processes and impacts this indicator relates to in the wider context, are essential and are discussed in this paper. Furthermore, in the selection of indicators for the purpose of our research certain criteria were considered simultaneously: (1) Communicability - What information an indicator can communicate and how comprehensible this information is for different actors; (2) Feasibility and data availability - Whether there is sufficient data for an indicator to be included and whether it is realistic for companies to integrate this indicator in their daily work practice; and (3) Scientific relevance - Whether the indicator is relevant for sustainability efforts on a larger scale and for related discussions in the scientific community. Insights related to these considerations are valuable for future developments in sustainability assessment in out-of-home gastronomy. The tool has been used to evaluate a number of dishes and results are deemed meaningful. However, assessments must not be understood as an accurate measurement but as an approximation of the sustainability of meals. At the level of individual indicators, they allow a detailed analysis and targeted optimization of recipes, while the aggregated results in the form of labels can be communicated well to customers. However, deficiencies and challenges, as discovered in the application phase of the project, demonstrate research gaps in the wider context. Finally, further steps for an integration of the tool in company processes and remaining options for companies to adjust the tool are discussed.

The article gives insights into the implementation process of sustainable management strategies in the food service sector. Furthermore, the normative requirements for sustainability in form of a mission statement, called "sustainable food services" are presented. The authors perceive this mission statement as a means to transfer current political demands (as in the SDG of the UN) into the sector. It could serve as a model for the entire food service sector to support and facilitate implementing aspects of sustainability into business practices with the help of sustainable management tools.

Since human nutrition is responsible for about 30 % of the global natural resource use and in order to decrease resource use to a level in line with planetary boundaries, Lukas et al. (2016) proposed a re-source use reduction in the nutrition sector by a factor 2 (Material Footprint). The catering sector needs clearly defined indicators to assess their business activities' impact on ecology, social aspects, economic value, and health status. Within the project NAHGAST two sets of indicators, called NAHGAST Meal-Basis and NAHGAST Meal-Pro were developed. The indicator sets are proposed to measure several, with sustainability-associated challenges, such as such as the ecological, social and economical effects, which may come along with the production and the consumption of a meal. Basically, the NAHGAST Meal-Basis deals with qualitative indicators, such as the amount of organic food per serving or the percentage of food wasted. This set is supposed to enable leaders to assess the sustainability of their meals and to visualize future improvements on a simplistic level. The NAHGAST Meal-Pro deals with a more sophisticated set of indicators, such as the carbon and material footprint or the cost recovery per meal. Both sets are underpinned with sus-tainable targets and elaborated as an Excel-based assessment tool, which is tested within a one-year case study. The usefulness and the limits of the tool, as well as current results of the implementation including pro-posed challenges, are discussed.

Public catering has become increasingly important in recent years. With increasing annual customers, the sector's impact on the environment is also growing continuously. At the same time, public catering offers a lever to promote sustainable nutrition that has rarely been used so far. Small changes in kitchen practices and food offers can thus be multiplied into a significant positive impact on environmental challenges, such as climate change or loss of biodiversity due to the large number of servings. In contrast to private households, management decisions in public catering can influence the food-related environmental impact of thousands of customers. This article deals with the nationwide level of greenhouse gas (GHG) emissions and resource use in the German public catering segment "business" and its saving potentials by different scenarios of unsupported and supported recipe revision. In this paper, we define "unsupported" as the intuitive optimization of recipes by employees of public catering businesses. In contrast, "supported" approaches had to meet specific target goals, for example of the Deutsche Gesellschaft für Ernährung; engl. German Nutrition Society or the sustainable level. Specifically, we will test how (A) an unsupported recipe revision, (B) a recipe revision based on dietary recommendations and (C) a recipe revision using scientific guidance affect the environmental impact of a dish. As a methodological framework, an online survey of public catering companies was conducted as well as a scenario analysis at menu level and at nationwide level. The results are based on empirical data on the one hand, and on extrapolations on the other. The results show that the nationwide implementation of recipe revision according to scientific guidance-such as concrete target goals for the GHG emissions per serving-can save up to 44% of resource use in the German business catering sector (which corresponds to 3.4 million tons of resources per year) and as much as 40% of GHG emissions (0.6 million tons GHG emissions per year). Even in the scenario of unsupported recipe revision, GHG and resource savings of up to 20% can be realized. The results show that public catering can reduce its material and carbon footprint by 20% overnight. Moreover, the findings show indications for the sustainable transformation of public catering. Nevertheless, it must be noted that these are some first steps of the transformation, which will require further changes with even greater impacts and political activities.