Human nutrition is responsible for about 30% of the global natural resource use. In order to decrease resource use to a level in line with planetary boundaries, a resource use reduction in the nutrition sector by a factor 2 is suggested. A large untapped potential to increase resource efficiency and improve consumers' health status is assumed, but valid indicators and general guidelines to assess these impacts and limits can barely be found. Therefore we will have a try to define sustainable limits towards the individuals' daily diet and therefore stimulate current available scientific debate.
Within the paper an examination of existing indicators and assessment methods is carried out. We set the focus on health indicators, such as energy intake, and environmental indicators, such as the carbon or material footprint. The paper aims to provide first, an assessment of core indicators to explore the sustainability impact of foodstuff, and second, a deeper understanding and a discussion of sustainable limits for those dimensions of food and nutrition. Therefore we will discuss several ecological and health indicators which may be suitable to assess the sustainabilty impact and indicate differences or similarities. As a result it becomes obvious that several ecological indicators "point in the same direction" and therefore a discussion about the variability and the variety of these indicators has to be faced in the future. Further the definition of sustainable levels per indicator is an essential aspect to get an idea about the needed barriers for a sustainable nutrition, by now first steps had been made, but no binding guidelines are available yet. Therefore the paper suggests a few indications to set up sustainable levels for health and environmental indicators, based on the idea to reduce the resource use level up to 30-50% in 2030.
Food labels are able to support consumers in making more sustainable food choices in out-of-home consumption situations. Thereby, the effect of changing consumption behaviour depends on the format of food labels and on the information it provides. In order to assess the importance of the amount of information as well as the design of food labels displaying sustainability aspects, we test different formats of food labels using a best-worst choice design. So far, no research tested a variation of information depth while keeping label designs fixed. We find clear preferences across both dimensions. Results indicate that consumers regard labels with a higher information depth as more helpful in order to choose a sustainable meal. For the label design it became obvious that the slider-design is preferred over footprints and traffic light label design.
Sustainable out-of-home nutrition can help achieve overarching sustainability goals through a transformation in demands of consumers in this growing market. Studies indicate that individual food choice behaviours in out-of-home settings relate to a wide set of personal, social and situational factors. These factors can be influenced by various intervention strategies. In an expert meeting and a focus group we invited caterers and consumers to generate, discuss and evaluate various practical intervention ideas. Both parties largely perceive the explored ideas as useful and agree on key intervention ideas. Overall caterers and consumers state to prefer nudging strategies over information and participation interventions.