sustainability Article Comparing “Leaf-to-Root”, “Nose-to-Tail” and Other Efficient Food Utilization Options from a Consumer Perspective Sina Nitzko * and Achim Spiller Department of Agricultural Economics and Rural Development, University of Göttingen, 37073 Göttingen, Germany * Correspondence: [email protected] Received: 31 July 2019; Accepted: 29 August 2019; Published: 2 September 2019 Abstract: The efficient use of natural raw materials is a key element of sustainable development and is also gaining importance in the food sector. Consumers are increasingly realizing that food is too valuable to be used only partially. However, consumer acceptance is an important precondition for establishing efficient food utilization options. A total of 470 German consumers were surveyed through an online-questionnaire where they had to evaluate three options each for the efficient use of plant-based foods as well as animal-based foods with respect to eight different criteria. The results show that the six options differed significantly regarding consumer acceptance. The efficient use of plant-based foods (especially non-standard fruits/vegetables and the “leaf-to-root” principle) was more accepted than the efficient utilization of animal-based foods. Furthermore, it can be seen that options using the by-products in a natural form were considered more acceptable than those which subject the by-products to some form of processing. These results provide an insight into the views of consumers on food waste reduction strategies, which are frequently debated in the sustainability discussion. Keywords: efficient utilization; food consumption; consumer research; food by-products 1. Introduction The efficient use of natural, renewable raw materials is a key element of sustainable development. The production of food, for example, is associated with high resource utilization. Not to utilize food as fully as possible for human nutrition is not only inefficient, but also results in unfavorable social, environmental, and economic effects on the sustainability of the food sector [1]. By-products are generated in varying amounts during the different stages of the value chain; for instance, in food retailing (e.g., fruits/vegetables with defects), in the food processing industry (e.g., pomace from the production of fruit juice), in food service (e.g., offal, skins and heads of fish) or at the end user or consumer stage (e.g., fruit peels). Although these by-products are often rich in valuable nutrients and would generally be perfectly suitable for human consumption, they are often used for other purposes or are disposed of [2]. While it was a matter of course in earlier times to use food holistically or more efficiently than nowadays [3], this practice has lost importance in the developed countries due to the existing surplus of food [4]. However, in recent times, a mindset change or rather a return to previous ideas has started, partly due to the increasing importance of sustainability in the food sector [5] and the public discussion about food waste and refuse [1]. It is being realized more and more that food is too valuable that only certain parts of it are used. Besides the sustainability-related advantages of an efficient use of food, there are also various options for saving costs and developing new products or dishes [4]. Different methods for the efficient use of both plant-based and animal-based foods are already known, which can be implemented at various stages of the value chain. 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The foods three include methods the for production the efficient of utilizationmechanically of animal-based separated meat foods and include reconstituted the production meat productsof mechanically (already separated established meat in the and food reconstituted industry), meatas well products as the “nose-to-tail” (already established principle in (cf. the Figure food 1).industry), In addition, as well due as to the the “nose-to-tail” importance of principle consumer (cf. acceptance, Figure1). Inthe addition, state of consumer-related due to the importance research of isconsumer discussed acceptance, for each method. the state of consumer-related research is discussed for each method. Figure 1. Options of efficient utilization of plant-based and animal-based foods used in the study (Source: Figure 1. Options of efficient utilization of plant-based and animal-based foods used in the study authors’ own illustration). (Source: authors’ own illustration). 1.1. Options for the Efficient Utilization of Plant-Based Foods 1.1. Options for the Efficient Utilization of Plant-Based Foods The “leaf-to-root” principle is one method of efficiently utilizing plant-based foods [18]. It means the holisticThe “leaf-to-root” utilization of principle agricultural is one plants; method i.e., not of onlyefficientl the “firsty utilizing cuts” (theplant-based parts of plantsfoods that[18]. are It meansusually the consumed) holistic areutilization used for of human agricultural nutrition plants; but also i.e. thosenot only parts the which "first are cuts" otherwise (the parts thrown of plants away (thethat so-calledare usually “second consumed) cuts”; are e.g., used peel, for roots, human leaves, nutrition stems, but and also stalks, those etc.) parts [18,19 which]. The are complete otherwise use Sustainability 2019, 11, 4779 3 of 21 of plants, which was common in households in earlier times, has been forgotten more and more [20]. Recently, the traditional, often forgotten knowledge about the holistic utilization of useful plants has been rediscovered and further developed. Thus “leaf-to-root” has developed into a culinary trend, which can be found in private households and in the gastronomy sector. While especially