Developing Sustainability Competencies Through Healthy and Sustainable Nutrition Workshops in Initial Teacher Training

Abstract

Education is key in promoting sustainable development across various sectors, including nutrition. Teachers play a critical role in shaping the mindset and skills of future generations, enabling them to effectively address global challenges. By integrating sustainability into their initial training, future teachers will have a greater understanding of the complexity of issues such as food security, environmental conservation, and social equity. It will also enable them to design teaching proposals that are in line with this complexity for their professional future. The objectives of this study are to show a curricular proposal that integrates healthy and sustainable nutrition contents into a degree in early childhood education and to assess university students’ competencies in sustainability issues. This is a pre-experimental quantitative study with a sample of second-year students enrolled in a subject called “Childhood, Health, and Nutrition” that lasted for one semester in three consecutive academic years. The results showed the effective integration of the project-oriented learning strategy as a teaching–learning methodology for the design of healthy and sustainable nutrition workshops for children aged 4–5. The workshops were presented in a simulated school context at the SDG Student Congress held at the university, and the sustainability competencies of these future early childhood teachers were assessed by a multidisciplinary team of experts using a specific rubric. The data obtained revealed a medium–high level of competency development in all three academic years analysed. This is a preliminary study that offers an example of how to integrate sustainability in a holistic manner linked to healthy nutrition contents aimed at training future teachers.

1. Introduction

The strategic interventions of the UN—initially through the Millennium Development Goals (2000–2015), and subsequently the 2030 Agenda for Sustainable Development (United Nations [UN], 2015; United Nations Development Programme [UNDP], 2015)—represent sophisticated multilateral attempts to recalibrate global developmental trajectories. These frameworks transcend traditional approaches to development by integrating the environmental, social, and economic sustainability dimensions into a holistic, interconnected paradigm (Albareda-Tiana et al., 2018a; Lozano, 2008). Despite these kinds of agreements, the current data remain alarming. According to the United Nations Development Programme (UNDP, 2024), agriculture is the largest consumer of water worldwide, and irrigation accounts for approximately 70% of all freshwater available for human consumption. The efficient management of shared natural resources and knowing how to dispose of toxic waste and pollutants are vital for sustainable production and consumption. The Food Waste Index Report (United Nations Environment Programme [UNEP], 2024) estimates that 132 kg of food is wasted every year per consumer worldwide. This waste has a considerable impact on the climate and the environment as 8% to 10% of total greenhouse gas emissions are associated with food that is not consumed (United Nations Framework Convention on Climate Change [UNFCCC], 2024). Reducing food waste is crucial for environmental sustainability, the economy, and the fight against world hunger.

However, beyond what governments, companies, or educational institutions can do, there is what we, as individuals and consumers, can do to mitigate the effects of this faltering and unsustainable global system (Mcdonald et al., 2012). Thus, in terms of individual consumers, a new conception of healthy eating is required that focuses less on what we need here and now and more on what the entire population may need today and in the future. As the Spanish Society of Nutrition points out in the theme addressed in its 17th edition (Spanish Society of Nutrition, 2018), there are five key elements that reflect the complexity and cross-cutting nature of today’s nutrition; we must move towards “5S Nutrition”: healthy, safe, satisfactory, sustainable, and social. Likewise, the Food and Agriculture Organisation of the UN’s World Health Organisation (FAO & WHO, 2019) conceives sustainable healthy diets as those that promote all dimensions of individuals’ health and wellbeing that have low environmental pressure and impact, including adjectives as accessible, affordable, safe and equitable. Diets that are culturally acceptable are also included. Therefore, as Hazley and Kearney (2023) pointed out, this definition is sophisticated and incorporates elements not only relating to health but also to environmental protection, social aspects, and economic considerations.

In the pursuit of achieving sustainable development in nutrition and in all areas of society, the role of education and teachers at all levels and in all disciplines is crucial. Teachers help future generations of citizens gain a proper perspective of the problems and challenges affecting humanity in order to responsibly engage in decision-making processes (Tilbury, 2011). As Junyent and de Ciurana (2008) explained, incorporating sustainability at the university level is not limited to including environmental content in the curricula of different subjects. In agreement with these authors, Tilbury (2011) and Rieckmann (2018) maintain that integrating sustainability into curricula involves incorporating knowledge, values, and sustainability criteria into teaching and research as essential dimensions in the training of future professionals. Universities hence play a key role in this process (Alam et al., 2021; Sustainable Development Solutions Network [SDSN], 2017, 2020).

The complexity of the current socio-environmental issues shows that it is impossible to find solutions to mitigate them except through cross-curricular skills that address complicated challenges (Sustainable Development Solutions Network [SDSN], 2017). As Brundiers and Wiek (2013) state, students must lead their own learning and address real-world problems. Given the complex nature of sustainability and of developing cross-curricular competencies, inter- or transdisciplinary training is necessary together with the implementation of teaching–learning methodologies that lead to the development of knowledge, procedures, attitudes, and values (Horn et al., 2024; Pritchard et al., 2018). With regard to these cross-curricular competencies, the Conference of Rectors of Spanish Universities identified four sustainability competencies that should be integrated into all university degrees. They include competencies in the (1) critical contextualisation of knowledge establishing inter-relationships between local and/or global social, economic, and environmental issues, (2) the sustainable use of resources and in the prevention of negative impacts on natural and social environments, (3) participation in community processes that promote sustainability, and (4) the application of ethical principles related to sustainability values in personal and professional behaviour (Cebrián et al., 2019, 2021). This paradigm shift in the educational process is especially important in initial teacher training, as prospective teachers will contribute to the education of future citizens from their different areas of teaching (Albareda-Tiana et al., 2018b, 2020; Brundiers et al., 2021). An assessment rubric was developed for those four competencies to be applied in education degrees. Each competency was divided into three levels of acquisition or development—(1) knows, (2) knows how, and (3) shows how and does—in accordance with Miller’s simplified pyramid, which turns out to be a very useful assessment tool (Miller, 1990).

Active methodologies such as project-oriented learning (POL) are suitable and recommended for developing competencies in sustainability (Tejedor et al., 2019). The predecessors of this method are the fathers of constructivism: Vygotsky, Bruner, and Piaget. Through this methodology, learning is built as an interaction between personal experiences and the network of mental structures developed. It allows students to establish rational and meaningful relationships with the environment and society. It is a strategy that enables the development of integrated and dynamic knowledge through the group search for solutions to real problems (Vilaplana et al., 2010). Students are in charge of their own learning and can increase their motivation by taking on greater responsibility (Basilotta Gómez-Pablos et al., 2020; Mosier et al., 2016).

Considering these facts with the idea of providing an example of integrating sustainability in higher education, the objectives of this study were as follows:

• To present a curricular proposal to integrate healthy and sustainable nutrition contents into the initial training of early childhood education teachers.
• To analyse university students’ level of cross-curricular sustainability competencies upon completing this proposal.

2. Materials and Methods

2.1. Study Design

The design of this study is quantitative and pre-experimental, with a post-test following an educational intervention repeated in three consecutive years in three convenience samples, all of them second-year students of the Early Childhood Education Bachelor’s Degree at the Universitat Internacional de Catalunya (UIC Barcelona, Spain).

Studies carried out using a pre-experimental design and therefore without a control group show a very weak relationship between dependent and independent variables (the development of competencies and the teaching proposal, respectively) (Kerlinger & Lee, 1999). To address this weakness, the intervention was repeated annually for three consecutive years to determine if the results obtained were consistent (see Figure 1).

As can be seen in Figure 1, a total of 51 female university students participated in the study (21 in the academic year 2021–2022, 18 in 2022–2023, and 12 in 2023–2024). The number of students participating in this study decreases from the first year to the last analysed because of the overall decline in enrolled students in the Early Childhood Education Bachelor’s Degree.

The results are not intended to be generalisable. This type of design is common in psychology and education and serves as a foundation or exploratory study for more consistent designs (Salas Blas, 2013). Kerlinger and Lee (1999) argued that these designs have no scientific value because they do not guarantee causality, and from the data found, theories cannot be built. However, they have value in applied research aimed at solving specific problems. The innovative method presented in this study aims to integrate sustainability—in its global meaning—linked to healthy nutrition in initial teacher training.

2.2. Educational Intervention

The curriculum of this degree programme does not specifically address sustainability, leaving this aspect to the teacher’s discretion. Therefore, considering that no training in sustainability is provided during the first year of the degree, it was decided to include sustainability content in the second-year subject called “Childhood, Health and Nutrition” (the 4th semester of the degree programme), starting in the academic year 2020–2021. This subject consists of a total of 60 h of face-to-face lessons that include several teaching–learning methodologies. Of those 60 h, 12 were spent using the POL methodology. This method was chosen to address sustainability content linked to aspects traditionally taught in healthy nutrition courses. As a starting point, the students were asked to design a nutrition workshop for children aged 4–5 years. They conducted research into healthy but also sustainable nutrition in a manner consistent with the curriculum for this educational stage in Catalunya (Diari Oficial de la Generalitat de Catalunya, 2023), which complies with the general premises for Spain (European Commission, 2025).

As required by the implementation of this active teaching–learning methodology, the students engaged in self-directed learning guided by the teacher of the subject (Mosier et al., 2016). They worked together in groups of 3–5 members in the classroom and, in line with the POL methodology (Tejedor et al., 2019), the process concluded with the presentation of the workshops they designed. In this case, as a novelty, instead of presenting them in front of the rest of the class, the students presented their workshop proposals to the university community at the SDG Student Congress organised by the UIC Barcelona Cooperation and Sustainable Development Office held in May (in each of its three editions). The students had the opportunity to leave the classroom and engage with the university community to showcase their work (Albareda-Tiana et al., 2024). The different phases of the POL methodology are detailed in Figure 2.

During the presentation of the workshop proposals, simulating the activities they would conduct at school with 4–5-year-old children, and showing the material created for that purpose, the future teachers’ sustainability competencies were assessed by a multidisciplinary team of experts using a specific rubric. This was innovative since, instead of being assessed solely by the teacher of the subject, each workshop proposal was given at least three different assessments from three different experts (economists, lawyers, biologists, engineers, and educators) as an expert panel evaluation. The selection of experts was made by the Office of Sustainability and International Cooperation at UIC. All experts had to meet one of the following criteria: 1. participate or have participated in a research project related to sustainability, 2. take part or have taken part in a teaching innovation project for the inclusion of the SDGs in the university, 3. be or have been in charge of a higher education subject that integrates education for sustainability into its programme, and 4. be a public administration or private company worker in sustainability matters. The number of experts varied, ensuring a minimum of three and a maximum of six in each case, depending on their availability during the morning that the Student Congress was held. This fact is worthy of note as being competent in sustainability requires a clear understanding of what the concept of sustainability represents in its three dimensions (social, economic, and environmental) and the existing inter-relationships between them (Lozano, 2006). By obtaining a multidisciplinary evaluation, the assessment becomes more objective, and, according to Bippert and Espinosa (2019), POL is an effective strategy for students to understand the reality around them and to experience new information that challenges their previous conceptions. Therefore, leaving the classroom, showing their work, and receiving evaluation and feedback from experts was considered ideal for their teaching–learning process.

2.3. Instrument and Data Analysis

Table 1. Assessment rubric for sustainability competencies in the degree of education (source: Albareda-Tiana et al., 2018b, 2020).

Sustainability Competency	Level 1. Knows (0.5–1)	Level 2. Knows How (1–1.5)	Level 3. Shows How and Does (1.5–2)
SUST 1. Competency in the critical contextualisation of knowledge, establishing inter-relationships between local and/or global social, economic, and environmental issues	Knows the functioning of natural, social, and economic systems and the mutual relationships between them	Analyses and understands the relationship between natural systems and social and economic systems	Can imagine and predict the impacts that the changes produced in natural systems may cause in social and economic systems and between each other
SUST 2. Competency in the sustainable use of resources and in the prevention of negative impacts on natural and social environments	Has basic knowledge of identifying possible socio-environmental impacts derived from educational actions	Knows how to develop educational actions that mitigate negative socio-environmental impacts	Designs and develops educational activities in which negative socio-environmental impacts are considered and incorporates mitigating measures

shows the rubric that was designed especially to assess sustainability competencies in the degree of education (Albareda-Tiana et al., 2018b, 2020). A panel of experts was in charge of evaluating the different workshop proposals. The experts used the rubric independently. Their evaluations (between 3 and 6 per workshop) were collected by the Office of Sustainability, which was responsible for calculating the average score given to each workshop by the panel of experts. The average scores (calculated on a scale of ten points) for each workshop were sent to the teacher in charge of the subject in which the pedagogical proposal was included. The anonymity of the panel members was maintained, and no details of each individual evaluation were provided, hence ensuring the freedom and objectivity of the process.

The information collected in each academic year was analysed using Excel software. The averages and deviations were calculated for each year and for each competency in order to further analyse and compare the results between the different years and workshops. The aim was to provide evidence of the impact of the curricular proposals put forward.

3. Results

3.1. Healthy and Sustainable Nutrition Workshops Designed

The initial premises that the teacher of the subject of “Childhood, Health, and Nutrition” pointed out were that all workshops had to comply with the specifications outlined in the regulations (Diari Oficial de la Generalitat de Catalunya, 2023), which determine the curriculum for early childhood education in Catalonia: (1) Article 3 (pedagogical principles) states that “global and meaningful learning experiences should be developed, based on play, experimentation, and movement in collaborative learning contexts” (p. 5); and (2) Article 4 (general objectives) states that “early childhood education should promote attitudes that foster equality among all genders, health, care, responsible consumption, sustainable habits, and respect for and appreciation of diversity” (p. 6).

Likewise, the learning objectives of the workshops that the students designed had to be framed within (a) Axis 3 of the curriculum: “a child who discovers the environment with curiosity” (p. 30); and (b) Specific competence 3: “exploring and recognising elements and phenomena of the natural world by establishing relationships between their own actions and the resulting consequences in order to acquire habits of sustainability and environmental conservation” (p. 34).

Following all these specifications, the workshops that the students designed in each academic year using the POL methodology (Figure 2), the activities developed, and the learning objectives pursued in each case are summarised in

Table 2. Workshop activities and learning objectives in academic year 2021–2022.

Academic Year 2021–2022
Summary of Activities *	Learning Objectives
Healthy and sustainable recipes
✓ The teachers create a memory game including the ingredients that will later be included in the recipes. ✓ The children choose different types of local food from the ones that appear in the memory game to design a healthy recipe. ✓ The children draw the ingredients and the dish created with them on poster board. ✓ The teacher collects all the poster boards and prepares a book of recipes to work with to explain the importance of healthy and sustainable diets.	Understand the influence of diet on health Identify simple, healthy and sustainable recipes using local ingredients
Honey: its sustainable production and nutritional properties
✓ The children sit on the floor in a circle, and the teacher reads them the story “l’abella i jo” (The bee and I) (Jay, 2017). ✓ The teacher builds the cells of a beehive using recycled cardboard rings filling the cells with cotton painted brown to simulate honey. The teacher explains the three types of bees: drones, workers, and the queen. ✓ The teacher uses an interactive model they created themselves with materials such as cardboard, stones, and wood to explain pollination and ask the students to try the model. ✓ The children experience a sensorial activity that involves natural honey. They smell, touch, and eat the honey while they talk about their feelings.	Explore the world of bees and their life cycle Understand the process of pollination and its role in nature Discover the nutritional properties of honey Learn about beekeeping practices and their socio-economic implications
The three “R’s”: reduce, reuse, and recycle
✓ The children watch a video file called “The three R’s” (Happy Learning, 2024). ✓ In groups of 3–5 members, they go to the school kitchen, where they ask the cook for any leftover food (fruit, bread, yoghurt, etc.) from that day’s meal, or food items that are about to expire. ✓ The children return to the classroom and create an easy recipe with the food obtained. ✓ They present their recipe to the rest of the class and clean up, sorting waste to recycle it in the different bins for organic, plastic, and paper waste. ✓ They all eat the food prepared and close the activity by singing a song [for example, the recycling song for kids (Boo Boo Gaga, 2024)].	Find solutions to reduce food waste Recognise the different types of waste generated in households Differentiate between reusing and recycling Reflect on world hunger while large amounts of food are wasted
Seasonal fruit: healthy and sustainable
✓ To start, baskets containing different kinds of fruit are displayed. The origin of the fruit is discussed to later introduce the concept of seasonal fruit in the region where the children live. ✓ Flashcards with images of fruit grouped in accordance with the four seasons of the year and others with images of those seasons are shown. The children play by connecting the cards (the fruit with the season they belong to). ✓ The teacher and the children create a supermarket in the classroom with boxes of toy fruit, cash registers, money, etc. They simulate shopping situations in which they are asked to buy fruit in season now. The teacher assigns the different roles of seller and buyer.	Identify seasonal fruit in the Mediterranean climate region Recognise the environmental impact of consuming fruit from other geographical areas Learn about the nutritional needs and properties of fruit

* For the activities that involve handling food, the families are asked about their children’s possible food allergies or intolerance beforehand.

,

Table 3. Workshop activities and learning objectives in academic year 2022–2023.

Academic Year 2022–2023
Summary of Activities *	Learning Objectives
Quinoa or rice?
✓ The characteristics of rice and quinoa cultivation (water, light, etc.), as well as their nutritional properties (cereal versus legume) are explained using images. ✓ The children are asked to choose one of the two and are put in groups of 3–5 members. ✓ The teacher hands out different ingredients to the groups, so they can prepare a salad including quinoa or rice, depending on which plant they have chosen. ✓ The children eat the salad they have prepared (tasting both) that day and are asked about taste, smell, and texture, where and how they are grown, properties and which one they prefer and why.	Learn about the nutritional properties of rice and quinoa Discover fun and healthy recipes using these foods Reflect on the environmental and socio-economic impact of growing both plants
Healthy and sustainable: cocoa!
✓ The teacher explains how cocoa is harvested as well as the chocolate production cycle to the children by using images for each step. These images are put on a pre-prepared mural where the different steps are numbered. ✓ The children try to put the images in the correct order to the previous mural. ✓ The teacher shows the journey from cocoa pod to chocolate bars produced in a factory to when it reaches our hands, using a pre-prepared toy model that contains different means of transportation (planes, cars, trucks, etc.). ✓ To conclude, the teacher explains the nutritional properties of cocoa and the different types of chocolate: milk chocolate, dark chocolate, etc. The children then make dark chocolate lollipops to take home and explain to their parents what they have learnt.	Discover the process of transforming cocoa into chocolate Introduce elements of sustainable agriculture related to cacao production Analyse the composition of different types of chocolate and reflect on excessive sugar intake
The impact of palm oil
✓ The teacher uses a video about a monkey called ‘Rafiki’. The monkey explains to the children that it is sad because the tree in which he hides and plays with his friends is going to be cut down to plant palm trees. ✓ Rafiki asks them for help and explains, in simple terms, how palm oil is obtained from the fruit of palm trees. He also tells them what humans use this oil for and shows them some foods, like cookies, that contain it. ✓ Rafiki asks the children to play with him. The teacher divides the children into groups of 3–5 members and gives them a word search to look up words like oil, palm, tree, fruit, cut, truck, etc., as well as a puzzle suitable for their age featuring Rafiki sitting in a tree. ✓ The children play talking together and with the teacher about what Rafiki explained to them.	Identify which foods may contain palm oil Analyse the advantages and disadvantages of palm cultivation Discover the characteristics and properties of vegetable oils
Test your taste buds! beef burger vs. tofu burger
✓ The children are asked to bring food-related playthings (such as fruit, milk cartons, toy shopping baskets, etc.) from home to build a supermarket in the classroom. Any missing items are created using cardboard or playdough. ✓ Role-playing games are organised in which the children act as shoppers, shop assistants, cashiers, etc. The children are given some play money (e.g., from Monopoly) and learn how to buy and sell. ✓ The teacher checks what they have bought (meat and/or vegetables) and explains how to make an animal or vegetable burger. ✓ The implications for the agriculture and livestock farming of producing one type of burger or the other are explained in simple terms, always taking a critical view of the pros and cons. ✓ The session concludes with an activity of blind tasting both vegetable and animal burgers for the children to differentiate the organoleptic properties of the burgers and choose the one they prefer without knowing their origin.	Analyse the nutritional properties of meat compared to vegetables Reflect on the water use in food crops and animal feed Differentiate the organoleptic characteristics of each type of burger

* For the activities that involve handling food, the families are asked about their children’s possible food allergies or intolerance beforehand.

and

Table 4. Workshop activities and learning objectives in academic year 2023–2024.

Academic Year 2023–2024
Summary of Activities *	Learning Objectives
Beyond meat
✓ The children are given a piece of cardboard and signs with images and the names of some ingredients that veggie burgers are made of, such as tofu, seitan, legumes, beef, etc. ✓ They have to match the names with the images and attach them to the cardboard. ✓ The students play a memory game with pre-made cards about plant ingredients of hamburgers. Every time they make a match, the nutritional properties of that ingredient are explained. ✓ They taste plant-based burgers of different flavours and colours) and talk about which one they like the most, comparing the taste with meat burgers.	Raise awareness of food unsustainability Explore different types of plant-based “meat” Discover healthy alternatives to animal meat
Growing calçots 1
✓ The activities start with a brainstorming session about the calçot: Do you know what it is? Where is it grown? Have you eaten it? Is it tasty? ✓ A video about its cultivation is shown [e.g., Plantem calçots; in English: We plant calçots (Hort urbà al balcó, 2024)] ✓ In green schools that have a garden, a field trip to the garden is organised to see how similar vegetables (if there are no calçots) such as leeks, carrots, onions, etc., are grown. ✓ If there is no garden, the children do a jigsaw puzzle the teacher has created showing the edible part of the underground vegetable and the stem above the ground.	Promote the consumption of local products Discover sustainable practices in agriculture Encourage learning through observation and interaction with the environment

¹ A local type of onion. * For the activities that involve handling food, the families are asked about their children’s possible food allergies or intolerance beforehand.

.

3.2. Workshop Presentations and Assessment of Sustainability Competencies

As explained above, the workshops were developed within the framework of the subject “Childhood, Health, and Nutrition” as part of its assessable tasks. The future teachers’ workshops accounted for 25% of the final assessment, and the mark was based on applying the sustainability competency rubric for SUST1 and SUST2 competencies developed by Albareda-Tiana et al. (2018b, 2020).

This rubric was completed during the interactive oral presentation of the workshops at the SDG Student Congress by a team of teachers from various disciplines as an expert panel (Figure 3). This multidisciplinary approach enabled us to carry out an assessment from different fields of knowledge, which is ideal when addressing global issues such as planetary unsustainability (Wiek et al., 2011). As mentioned earlier, over the course of three years, a total of ten workshops were presented. Some of the materials and resources that the students created for their presentations are shown in Figure 4.

The competency values that the students obtained in each workshop, as well as the annual average and standard deviation, are shown in

Table 5. The competency values obtained in each workshop and the annual average and standard deviation in each academic year.

Academic Year			SUST 1 (Over 10)	SUST 2 (Over 10)
2021–2022	1	Healthy and sustainable recipe book	6.5	8.95
	2	Honey: its sustainable production and nutritional properties	8.15	8.15
	3	The three “R’s”: reduce, reuse, and recycle	8	7.9
	4	Seasonal fruit: healthy and sustainable	7.1	7.9
		Average	7.43	8.22
		SD	0.77	0.49
2022–2023	5	Quinoa or rice?	6.5	9.5
	6	Healthy and sustainable: cocoa!	7.1	6.25
	7	The impact of palm oil	6.65	8.35
	8	Test your taste buds! beef burger vs. tofu burger	6.9	7.1
		Average	6.78	7.80
		SD	0.26	1.42
2023–2024	9	Beyond meat	10	7.5
	10	Growing calçots	5.5	6.5
		Average	7.75	7.00
		SD	3.18	0.70

. It is observed that, on average, the SUST2 competency was higher each year (ranging from 7 to 8.2), although it was not significantly higher than SUST1 (ranging from 6.78 to 7.75). It should be noted that in the third year (the academic year 2023–2024), only two workshops were presented due to the low number of students enrolled in the subject (see Table 4). This resulted in very unequal marks, as indicated by the standard deviation (3.18). It can be said that, by the end of this educational intervention using the POL methodology, a medium–high level of both competencies (between the second and third levels described in the assessment rubric) was achieved every year it was implemented.

Figure 5 shows a graphic representation of the marks obtained in each competency for each workshop. In all cases, the pass mark (5) to evaluate the different workshops was exceeded, which means the students acquired the necessary knowledge regarding healthy and sustainable nutrition. For instance, the workshop called “Beyond meat” (Workshop 9) achieved the highest score in the SUST1 competency (10/10), indicating that the students in this group demonstrated the highest level of competency in imagining and predicting the impacts of changes in natural systems on social and economic systems and on each other. The workshop on the impact of palm oil (Workshop 5) scored the highest in the SUST2 competency (9.5/10), showing that the future teachers in this group were highly competent in designing and developing educational activities that take into account negative socio-environmental impacts and incorporate mitigation measures.

4. Discussion

Regarding the first objective of this study, which is to present a curricular proposal for integrating healthy and sustainable eating into the initial training of early childhood education teachers in line with successful teaching approaches, the information presented shows the suitability of this approach. It combines the use of POL as a teaching–learning methodology within the framework of the “Childhood, Health, and Nutrition” subject with the presentation of the final project (interactive workshops for children) in the context of the SDG Student Congress organised at the University.

The students took responsibility for their own learning process and addressed real and relevant problems (Hadim & Esche, 2002; Rodríguez et al., 2015). In this case, they addressed their future teaching practice in early childhood education by creating and presenting a workshop that promoted healthy and sustainable nutrition among children aged 5–6 years to the university community. This approach fulfilled the central premise of this strategy, which was the need to link theory with practice, allowing students to solve problems close to the professional context in which they will be developed (Fernandes, 2014). This promotes an education based on active learning, where the student is at the centre (Browne-Ferrigno & Muth, 2012). As the authors indicate, a traditional instruction system does not prepare students to face work and life in our current complex and constantly changing society (Tamim & Grant, 2013).

Furthermore, it is clear that the students were able to work on the three key components of their initial training in accordance with the recommendations of the TALIS report (Organisation for Economic Co-operation and Development, 2024): sound academic knowledge of healthy and sustainable food, pedagogical elements in line with educational theory, and practical experience that complements the theory in a university classroom.

Traditionally, this subject has only considered the teaching and learning of healthy habits, particularly stressing the need to follow a healthy diet. This included content on the nutritional properties of different foods, which foods should be consumed and in what proportion, depending on various factors such as age or physical activity, in order to enjoy optimal health (Martinez-Gonzalez et al., 2000; Hansen & Thomsen, 2018). On a practical level, the students were asked to design and develop a cooking workshop for children aimed at promoting health and developing STEM skills (Fernández-Morilla & Fuertes-Camacho, 2019).

However, alarming data on the current planetary situation, including the FAO (2011) reports on food waste and the significant contribution of the food footprint to the individual ecological footprint (Collins et al., 2020; Fernández et al., 2016), prompted a change in the teaching–learning approach of this subject. The focus shifted from what individuals need to ensure their wellbeing to what they should consume to optimally meet their nutritional needs while ensuring access to quality food for others today and in the future. The subject began to include teaching and learning about healthy and sustainable eating, adding the latter adjective as numerous organisations do today when defining the concept of healthy nutrition (FAO & WHO, 2019; Hazley & Kearney, 2023; Spanish Society of Nutrition, 2018).

Fináncz et al. (2023) conducted a systematic review of intervention programmes in early childhood education developed to deliver health education in schools. They found that most studies focused on physical activity and healthy nutrition to prevent obesity and decrease screen time, but very few combined health education with environmental sustainability. Amongst those few studies, Korniaki et al. (2021) show how the pre-school setting can increase young children’s knowledge about healthy eating and sustainability and claim that this stage plays a key role in promoting health and environmental awareness. Lee et al. (2022) found that the SAGE model (Sustainability via Active Garden Education) using a garden-based curriculum was helpful to increase physical activity and the consumption of fruit as part of an obesity prevention plan for 3–5-year-old children. Similarly, López-Banet et al. (2022) describe using ideas about known fruit, vegetables, and pulses to help 3–5-year-old children develop an interest and research skills about how foods grow and develop. In any case, in line with Güler Yıldız et al. (2021), studies on educational interventions in early childhood education mainly refer to the environmental dimension of sustainability but do not address sustainable and healthy nutrition holistically, considering social and economic dimensions as well. In order to extend sustainability in health programmes implemented in schools and to start considering sustainable nutrition globally, specific proposals need to be integrated into initial teacher training, as teachers, together with parents, are responsible for educating children.

This leads us to the second objective, which is to analyse the students’ level of sustainability competencies at the end of this proposal. During the presentation of their workshops, all the groups demonstrated a medium–high level of competency for both SUST1 (competency in the critical contextualisation of knowledge, establishing inter-relationships between local and/or global social, economic, and environmental issues) and SUST2 (competency in the sustainable use of resources in the prevention of negative environmental and social impacts). According to Miller’s (1990) levels, the students “know how, and show how and do” (see Table 1). This shows that the future teachers who participated in this proposal are duly trained to develop classroom interventions that address healthy nutrition, incorporating this new perspective of sustainability in its three dimensions. They hence fulfil the goal of initial teacher training, which is to demonstrate the development of their competencies for the future practice of the profession.

As shown in Figure 3, the development of any one competency does not predominate but varies depending on the workshop. The highest value for the SUST1 competency (Workshop 9) coincides with the lowest value for the same competency (Workshop 10) in the three years analysed. Thus, in the academic year 2023–2024, although the average value was 7.75, the standard deviation was very high (3.18). The reason may lie in the topics covered: while the first workshop dealt with plant-based alternatives to meat, the second focused on growing calçots, a variety of onion typical of Catalonia. In the first case, there is extensive literature and a well-developed market today (Hu et al., 2019; Joshi & Kumar, 2015; Nestlé Global, 2024), which enables us to gather numerous data and design attractive and sophisticated activities for children (such as tasting different types of plant-based burgers). In contrast, references for the second workshop are limited to the local context. Agricultural issues related to a specific onion variety (Generalitat de Catalunya, 2025; Simó Cruanyes, 2013) might be more complex to address when developing a workshop for children. Future teachers must show that the activities proposed help understand the interconnections of the different dimensions of sustainability and the need to express and convey them clearly.

A limitation of the study could be that the future teachers’ individual or group competency level prior to including the proposal in the curriculum is unknown, as the methodological design includes a post-test but not a pre-test. However, this study is carried out in the second year of the degree in early childhood education and sustainability is not explicitly integrated in any other subject during the first year, so the starting point referred to these competencies could be similar (Figure 1). This study therefore promotes a way of integrating sustainability into the curriculum, beyond incorporating environmental content into the syllabus of the subject, to achieve effective integration, as recommended by the authors (Junyent & de Ciurana, 2008; Rieckmann, 2018; Tilbury, 2011). If nutrition, as well as other topics in early childhood education, incorporates the perspective of sustainability, the three pillars of sustainability should be addressed, not just the environmental pillar. In all the work developed so far, only the environmental pillar has been considered. By doing so, children are not able to understand the interconnections that exist between the three pillars (Lozano, 2006, 2008). Dealing with sustainability in its three dimensions will enable children to realise the environmental, economic, and social implications associated with their actions.

Although the results of this case study are not intended to be generalisable, they do demonstrate the success of an innovative teaching–learning alternative under similar conditions (a small group of students, all female, the same age of 20–21 years, at a private university, in a mandatory course, etc.) after being repeated three times.

5. Conclusions

First of all, in presenting a curricular proposal to integrate healthy and sustainable nutrition into the initial training of early childhood education teachers, we conclude that the POL strategy, combined with workshops on healthy and sustainable food as developed at the SDG Student Congress (held at UIC Barcelona) is a practical and effective way to integrate sustainability into the degree in early childhood education. This complies with the UN guidelines urging higher education institutions to lead educational change towards cross-curricular and global training, enabling future professionals to solve current complex issues, including healthy and sustainable nutrition.

Secondly, for our objective of assessing students’ level of sustainability competencies at the end of this proposal, we found a medium–high level of competency in sustainability (SUST1 and SUST2). This means that students involved in this teaching strategy can imagine and predict the impacts of changes in natural systems on social and economic systems and the way they interact. They can also design educational activities using appropriate materials for children aged 4–5 that consider negative socio-environmental impacts and incorporate measures to mitigate climate change. In today’s increasingly challenging world, teachers have a crucial role in building a sustainable future for new generations. Early childhood education lays the foundation for lifelong learning, and it is therefore essential to instil sustainable values in children from an early age.