Towards Reshaping Children’s Habits: Vitalia’s AR-Gamified Approach

Abstract

This paper presents the design, development, and pilot deployment of Vitalia, an AR-gamified application targeting the formation of healthy habits in primary education children. Developed within the EU DUSE project, Vitalia integrates physical activity, nutritional education, and immersive storytelling into a gamified framework to promote sustained behavioral change. Grounded in evidence-based behavior change models and co-designed with health, nutrition, and physical activity experts, the system envisions high daily engagement rates and measurable knowledge improvements. The concept positions Vitalia as a scalable model for child-centric, ethically responsible digital health interventions, with the potential to be integrated into school curricula and public health strategies.

1. Introduction

The global rise in childhood obesity and Type 2 Diabetes Mellitus (T2DM) represents a major public health concern. Historically considered adult-onset, T2DM is now increasingly seen in youth, with over 41,000 new pediatric cases diagnosed globally in 2021 (Youth-Onset T2DM: The Epidemiology of an Awakening Epidemic (PubMed Central), online at https://diabetesjournals.org/care/article/46/3/490/148482/Youth-Onset-Type-2-Diabetes-The-Epidemiology-of-an (accessed on 8 July 2025)). Obesity, affecting 160 million children and adolescents, remains a key driver. According to the WHO and IDF, poor diet and physical inactivity are among the leading modifiable risk factors contributing to premature mortality and the development of non-communicable diseases such as diabetes and cardiovascular disease. In 2021 alone, diabetes caused 3.4 million deaths worldwide, a toll expected to increase without preventive action (International Diabetes Federation (IDF) Diabetes Atlas, online at https://diabetesatlas.org/ (accessed on 8 July 2025)).

These trends highlight the need for proactive strategies that address behavioral risk factors early in life. Traditional health education methods often fall short in changing children’s daily routines. Consequently, there is growing interest in immersive and playful interventions that can reframe health-related behaviors. Preventive tools that integrate physical activity, nutritional awareness, and behavioral reinforcement, especially those delivered through familiar, engaging technologies, offer promising potential for reshaping lifelong habits.

According to the WHO and IDF, poor diet and physical inactivity are among the top modifiable risk factors contributing to the global rise of non-communicable diseases (NCDs), including obesity, cardiovascular disease, and Type 2 Diabetes Mellitus (T2DM). In 2021, diabetes caused 3.4 million deaths worldwide, and the number of people living with diabetes rose to 830 million by 2022. Critically, a significant portion of this burden stems from preventable childhood behaviors that persist into adulthood. These trends underline the urgency for early, engaging, and evidence-informed interventions that reshape children’s daily habits in sustainable ways.

The DUSE EU project, standing for “Counteracting Diabetes USing Interdisciplinary Educative Programs”, directly addresses this critical need by developing comprehensive, interdisciplinary educational programs. At the core of the DUSE initiative is the Vitalia mobile application, a novel digital tool designed to promote healthier habits in children and adolescents. This paper addresses the research gap in integrated, narrative-driven, AR-based mobile health interventions tailored for early prevention of T2DM and obesity in children. Unlike prior works that isolate either physical activity or nutritional literacy, the introduced Vitalia app aims to unify both within a structured behavioral change framework grounded in educational and psychological theory. Our central research objective is to design and preliminarily evaluate a modular, multilingual, gamified AR application that promotes healthy lifestyle habits among children in primary education.

This study is guided by the following exploratory research questions:

• RQ1: To what extent can a narrative-centered, behaviorally informed mobile AR experience enhance motivation, engagement, and daily adherence to health-positive actions?
• RQ2: Can such an approach contribute to reshaping children’s habits and their conceptual world model?

While the present paper reports on the formative design and pilot implementation of Vitalia, it also provides the basis for a follow-up, hypothesis-driven evaluation. In that context, the following analytic aims are proposed for future investigation:

• Aim 1: To examine whether Vitalia users exhibit higher daily engagement adherence than controls over a 4-week period, as measured by in-app logs, following gamified behavioral tracking approaches used in prior pediatric health interventions [1,2].
• Aim 2: To assess whether post-intervention motivation scores (e.g., via the Intrinsic Motivation Inventory) increase among users relative to their baseline, consistent with findings in AR and exergame-based studies [3,4].
• Aim 3: To explore whether intrinsic motivation mediates the relationship between app use and adherence to health-positive behaviors, drawing on principles from self-determination theory and the gamification literature [5,6,7].

The app’s design is informed by an extensive analysis of the educational and psychological needs of its target users, aiming to leverage the power of play and interactive technology for lasting behavioral change. Vitalia is a product of a multinational EU initiative, aiming to provide a transnational, scalable solution for health promotion in children. The app’s architecture and deployment plan reflect this European scope: its language system is modular, currently supporting five languages (Greek, English, Italian, Romanian, and Ukrainian), and it was explicitly designed for cross-border adaptation and even cultural contextualization. Therefore, while initial testing was conducted in Greece, the app is not intended as a local intervention but as a flexible, multilingual platform that can be deployed across diverse educational and healthcare systems. This paper reports on the conceptual design, implementation, and preliminary piloting of Vitalia, without aiming to evaluate long-term behavioral outcomes at this stage.

2. Background and Related Work

The escalating global prevalence of childhood obesity and T2DM necessitates innovative approaches to health education and habit formation. Digital technologies, particularly mobile applications, augmented reality (AR), and gamification, are increasingly recognized as powerful tools to address these public health challenges by engaging young populations in meaningful and sustainable behavioral change initiatives. Because the onset of T2DM in youth is strongly influenced by lifestyle and behavior, preventive interventions are most effective when grounded in behavior change science.

Digital interventions for child health promotion, especially those addressing nutrition and physical activity, have proliferated in recent years, reflecting the increasing adoption of mobile devices by children. Notable efforts include applications like “FitQuest” [8], which blends physical exercise with augmented reality, and “Fooya!” [9], a game targeting food choice education. These systems, while innovative, often lack longitudinal habit-forming scaffolds or narrative immersion. Recent reviews on serious games in pediatric diabetes prevention (e.g., [10,11]) suggest that gamified tools remain underutilized in early-stage T2DM intervention strategies. These approaches strengthen the conceptual validity of digital interventions and support the structured development of tools that aim to reshape children’s health behaviors [7,10].

Gamification, defined as the application of gaming elements and principles in non-game contexts, has demonstrated significant potential in promoting healthy habits among children and adolescents. Systematic reviews indicate a positive impact of gamification on modifying children’s eating behaviors, enhancing nutritional knowledge, and encouraging physical activity [12,13,14]. Studies show that gamified interventions can improve motivation, commitment, and engagement to healthy behaviors, often by incorporating elements like points, badges, leaderboards, and interactive challenges [2,12,15]. This approach leverages children’s intrinsic motivation for play and competition, fostering deeper engagement than traditional educational methods [13,14,16]. While the effectiveness is widely acknowledged, some reviews suggest a need for further research to validate theoretical models and assess long-term sustainability [15,16]. Gamification as a health intervention method has been linked to increased motivation and behavior adherence, particularly in children [7]. However, the success of such tools depends on balancing engagement with educational efficacy, and only a few studies, such as [3], have attempted to empirically link game mechanics with behavioral change indicators in younger age groups. Vitalia contributes to this space by combining AR-enhanced embodied interaction with a narrative-driven behavior model, grounded in validated psychological theories and behavior change frameworks.

Among prior efforts, “Escape from Diab” and “Nanoswarm: Invasion from Inner Space” [17] represent prominent narrative-based games designed to promote healthier eating and physical activity in youth populations, both grounded in Social Cognitive Theory and extensively evaluated through controlled trials [3,18]. These games integrate storylines with multiple sessions to drive behavior change and have inspired subsequent educational tools. Their design, grounded in Social Cognitive Theory and behavior modeling, is documented in [19], and their evaluation in a randomized trial in [1]. However, most narrative-based games, such as those described in [19], are not optimized for mobile AR use, nor do they target the formative age range of primary education, as Vitalia does. Moreover, reviews such as [10,11] underscore that early-stage T2DM prevention has remained underrepresented in the design of such tools, especially in non-clinical, lifestyle-focused contexts. Vitalia explicitly addresses this gap by embedding theoretically grounded health education in a playful, mobile-first AR environment tailored for primary education children.

Beyond the general impact of gamification, a number of behavioral and psychological theories provide formal grounding for its effectiveness in health interventions targeting children. Self-Determination Theory (SDT) [5,6] explains how autonomy, competence, and relatedness enhance intrinsic motivation, which is critical for sustaining engagement in educational health apps. The COM-B model [20] frames behavior as a result of Capability, Opportunity, and Motivation, and has been widely adopted in the design of behavior-change interventions in mobile health. Social Cognitive Theory (SCT) [21,22] contributes the concepts of observational learning, self-efficacy, and reinforcement, all of which are present in game-based learning environments. The Behavior Change Wheel (BCW) framework [20] builds on COM-B and provides a taxonomy of behavior change techniques including prompts, rewards, and self-monitoring, mechanics commonly used in gamified mobile applications like Vitalia. These theoretical underpinnings strengthen the conceptual validity of digital interventions and support the structured development of tools that aim to reshape children’s health behaviors.

Complementary to these frameworks, Fogg’s Behavior Model (FBM) [23] offers a minimalist yet practical lens to explain how motivation, ability, and prompts must converge for behavior to occur. It is particularly relevant in mobile app design, where real-time triggers and simple tasks are optimized to match user capacity. Additionally, the Transtheoretical Model (TTM), or Stages of Change model [24], emphasizes that users progress through sequential phases, from precontemplation to maintenance, when adopting new behaviors. This phased approach supports adaptive gamification strategies, where mini-games and challenges align with a child’s readiness and ability to commit to healthy habits. While the Transtheoretical Model (TTM) has been widely applied in adult health interventions, its application in pediatric contexts, particularly in mobile gamified settings, remains limited. Existing studies have primarily focused on adolescents or general education platforms rather than young children [25]. In this respect, Vitalia constitutes a novel contribution by operationalizing multiple behavior change models (SDT, COM-B, TTM, FBM) in a unified, AR-enhanced, narrative structure tailored specifically for children in primary education. To our knowledge, this is one of the first mobile applications to embed stage-based behavioral progression and adaptive task design within a game-based daily habit loop for early diabetes prevention. Together, these models enrich the theoretical backbone of Vitalia by justifying both the simplicity of micro-interactions and the progressive narrative scaffold that encourages gradual yet lasting behavior change. Empirical evidence supports the relevance of these models in pediatric digital health. A recent systematic review in BMC Public Health found that TTM-based interventions significantly promoted physical activity among children and adolescents [26]. Similarly, implementation studies have successfully applied the COM-B framework to understand determinants of wearable device engagement in youth [27]. These findings underscore the appropriateness of these behavior-change models in designing digital interventions for young users, and validate our choice of frameworks in Vitalia.

Augmented reality (AR) technology, which overlays digital information onto the real world, offers unique opportunities for immersive and interactive learning experiences. Unlike virtual reality (VR), AR allows users to remain connected to their physical environment while interacting with virtual content, enhancing engagement and active participation [28]. In pediatric healthcare, AR has been explored for various applications, including educating children about clinical research concepts, distracting them during painful medical procedures, and improving their understanding of medical conditions [28,29]. AR is particularly effective in physical activity interventions, where it can provide real-time visual feedback and make exercises more engaging by projecting virtual objects or characters that children can interact with [29,30]. This technology can personalize learning experiences and make health concepts more tangible and appealing to children [29]. Nevertheless, one may need to consider that while AR shows promise for increasing motivation and supporting development, some studies also highlight potential risks such as increased screen time, the challenge of distinguishing what is virtual from reality, and the need to examine long-term effects [31].

While previous interventions have explored gamification or AR independently, or in narrowly scoped combinations, Vitalia represents a distinctive integration of narrative, embodied interaction, and multi-level behavioral scaffolding within a modular, multilingual mobile platform. To our knowledge, no existing system operationalizes a full suite of behavior change theories, COM-B, SDT, SCT, TTM, FBM, within an AR-enhanced, story-driven mobile framework that simultaneously targets both physical activity and nutritional literacy in children in primary education.

Mobile health applications are increasingly utilized for self-management and prevention of chronic diseases, including diabetes. For youth, these apps offer a convenient platform to deliver educational content, track progress, and provide support for managing conditions like Type 1 Diabetes (T1D) and for preventing T2DM [32,33,34]. Reviews indicate that mobile apps can improve engagement to healthy behaviors and enhance glycemic control, though further high-quality, long-term research is often recommended to fully ascertain their clinical effectiveness and integrate them into routine care [32,34]. Despite challenges related to user acceptance and usability, mobile health solutions remain a promising avenue for empowering patients and fostering proactive health management [32,34].

The combination of AR and gamification presents a powerful synergy for pediatric health interventions. Gamified AR applications can create highly immersive and motivational environments that encourage physical activity, cognitive development, and mental well-being [29,30,35]. Research has explored this combination for diverse applications, including improving balance and coordination, addressing mood interventions, and promoting compliance to health guidelines [2,30,35,36]. By integrating game mechanics with interactive AR experiences, these interventions can make health goals more attainable and reinforce desired behaviors through engaging play [35]. The appeal of such combined technologies is particularly strong for the current generation of digitally native learners, who are accustomed to interactive and technology-driven experiences [30].

Building upon the established efficacy of gamification and the immersive potential of AR in pediatric health, this paper presents the Vitalia mobile app, which was developed within the EU project DUSE, and integrates these elements through a structured educational framework aimed at reshaping children’s habits to counteract diabetes. While the existing literature demonstrates the individual strengths of gamification, AR, and mobile health for various health aspects, Vitalia seeks to offer a comprehensive, narrative-driven solution that directly addresses physical activity and nutrition for diabetes prevention in a holistic manner. Narrative-based learning is increasingly recognized for its motivational value and knowledge retention, especially in young learners. Vitalia’s fantasy framing aligns with the concept of narrative persuasion and story-based instruction [37,38], providing an emotionally resonant context for action-based health learning. Narrative-based approaches to health gamification have been previously explored in systems like “Escape from Diab” and “Squire’s Quest!” [4,19], which embed dietary and activity guidance into story arcs. Vitalia extends these ideas through AR-based daily interactions, modular narratives tied to behavior change techniques, and parent–child co-play cycles, creating a more embodied and routine-integrated intervention. Vitalia’s design reflects principles from both motivational and behavioral theories, including staged behavior progression (TTM), prompt-driven interactions (FBM), and intrinsic engagement drivers (SDT). Mini-games serve as micro-interventions that align with daily prompts and gradually scaffold user commitment across weeks of play. By combining established principles of behavior change, the motivational power of gamification, and the experiential learning capabilities of AR within a user-friendly mobile platform, Vitalia aims to contribute significantly to the ongoing efforts of promoting healthier lifestyles in children, by combining AR-enhanced embodied interaction with a narrative-driven behavior model, grounded in validated psychological theories and behavior change frameworks [3,10,23]. Vitalia’s behavior change strategy is grounded in multiple psychological frameworks. Its use of real-time feedback, progression systems, and embodied interaction aligns with the COM-B model [20] and the Behavior Change Wheel [20]. Moreover, the storytelling layer, centered around the mythic ecology of Vitalia, draws from the narrative persuasion model [37] and supports emotionally anchored learning [38]. The progressive, scaffolded nature of its tasks further reflects stages from the Transtheoretical Model (TTM) [24], acknowledging how users shift from awareness to commitment and maintenance of habits. These theoretical foundations justify the integration of micro-games, AR embodiment, and playful rituals as valid triggers for habit-forming educational engagement. Unlike many gamified health apps that operate in a static or episodic mode, Vitalia implements a progressive, day-by-day narrative arc combined with AR-triggered physical tasks and personalized reinforcement. This aligns with behavior change models (e.g., COM-B, SDT) and is rarely found in similar applications.

3. “Saving Vitalia”

The present text focuses on the design, theoretical grounding, and pilot-level formative assessment of the Vitalia application. While not structured as a controlled trial, the work is situated within a human-centered design research methodology, combining theory-based content development, expert reviews, and in situ testing with children to validate functional and pedagogical assumptions.

The Vitalia app introduces children to a vibrant, imaginary land where environmental harmony is sustained by a magical olive tree nourished by elemental seeds, each representing water, air, soil, and fire. When mischievous creatures called Greedlings scatter the seeds and disrupt the ecosystem, players assume the role of Guardians tasked with restoring balance. To recover the seeds, children complete daily challenges rooted in physical activity and nutritional learning. As they succeed, the world of Vitalia gradually heals, guided by the reappearance of the Spirits of Nature. The narrative progression motivates consistent engagement, weaving healthy habits into an epic, child-friendly quest for ecological restoration.

The application targets primary education children and provides daily tasks grounded in physical activity and nutritional learning, all embedded within a narrative-driven, augmented reality (AR) framework. These tasks aim to reinforce both cognitive and embodied dimensions of behavior change through repetition and engagement in the story world. By combining AR-guided physical exercises with interactive nutrition games, the app seeks to instill healthy habits in a way that is both educational and immersive.

Following an analysis of technical feasibility, the educational mini-games in Vitalia were grouped into two core strands: physical exercise and nutrition. The daily low-to-moderate-intensity exercise program includes stretching, core movement, jumping and skipping rope, upper body and head movement, lower limb movement through walking, and upper limb activity with hands. Complementing these are high-intensity workouts, scheduled three times per week, featuring sit-ups, push-ups, planks, jumping jacks, and high-knee running. Nutritional learning is embedded through four playful activities: matching foods with nutrients, constructing the food pyramid, choosing appropriate meals for different times of day, and identifying singular foods in groups of four. In addition, the app provides the significant ability for children and their parents to build a weekly meal plan based on concepts and studies of nutritionists in the DUSE project. Figure 1 (Note: The English interface is shown in the presented figures for demonstration. The app already supports five languages and multilinguality in general.) shows an overview of the design, structure, and interaction flow of Vitalia.

Figure 1. Overview of the Vitalia system structure and user interaction flow.

The app makes use of the device’s front-facing camera, allowing players to mirror themselves while completing exercises. Augmented graphical elements and supporting audio guide the children during the activity, ensuring an engaging and visually supportive experience. Importantly, no recording or storage of personal data occurs; all visual input is used only transiently for gameplay purposes, in accordance with ethical and privacy regulations. Figure 2 shows consecutive screenshots during the progress in the stretching AR mini-game, while testing the app.

Figure 2. Illustrative scenes from the AR mini-game for stretching.

Each mini-game in Vitalia is explicitly designed to align with one or more behavior change mechanisms. For example, the physical AR tasks reinforce the “Opportunity” dimension of the COM-B model by encouraging embodied movement and daily engagement in outdoor or open-space environments. The food classification and daily ritual challenges foster “Capability” by promoting nutritional literacy, memory consolidation of food groups, and the cognitive framing of healthy eating as a routine behavior. The point system, narrative milestones, and surprise rewards sustain “Motivation” through both intrinsic (story-driven purpose, character alignment) and extrinsic (achievements, streaks) reinforcement. This multifaceted mapping of features is guided by the behavior change technique (BCT) taxonomy, which underpins effective interventions through mechanisms such as goal setting, self-monitoring, feedback, reward anticipation, and environmental restructuring. By integrating these principles, Vitalia supports incremental habit-building and the transfer of in-game decisions into real-world health actions, in alignment with evidence-based models of behavioral change.

To enable a meaningful evaluation of user progress and behavioral change over time, Vitalia integrates a lightweight analytics module that captures structured data on player interaction. For each player, the system records metrics such as the timestamp, duration, and performance score for every mini-game session. Since activities can be repeated multiple times across different days, these data form a longitudinal profile of engagement and skill development. By aggregating these interactions, educators and health experts can track consistency, improvement patterns, and potential areas of difficulty. These indicators offer a non-invasive, ethically compliant way to assess both cognitive acquisition (e.g., nutritional literacy) and motor engagement (e.g., exercise frequency and responsiveness). Importantly, all data collection is seamlessly embedded within the overarching narrative, so that children perceive their actions not as tests or measurements but as vital contributions to the restoration of the fictional world of Vitalia.

Last, it should be emphasized that the design of all mini-games and the overall educational concepts behind Vitalia is firmly grounded in research conducted within the framework of the DUSE EU project. The included physical activity routines and nutritional tasks were not arbitrarily selected but were carefully developed in collaboration with experts in childhood nutrition and physical education. Their work in DUSE involved synthesizing current best practices, behavioral guidelines, and age-appropriate recommendations to ensure that every interactive element contributes meaningfully to children’s health literacy and habit formation. This interdisciplinary foundation ensures that the gamified experience is not only engaging but also pedagogically sound and aligned with established developmental and wellness objectives. The app is accessible at https://duse-game.athenarc.gr (accessed on 8 July 2025).

Table 1 maps the core health behaviors targeted by Vitalia to their corresponding game mechanics, behavior change techniques (BCTs) from the Michie et al. taxonomy [20], and engagement strategies. This mapping clarifies the design rationale by linking each in-game activity to an explicit psychological or educational outcome, grounded in models such as COM-B, Self-Determination Theory (SDT), and the Behavior Change Wheel. The inclusion of extrinsic (points, rewards, surprises) and intrinsic (narrative immersion, co-design) motivational elements ensures sustained engagement and educational efficacy across activities.

Table 1. Mapping of targeted behaviors, game mechanics, behavior change techniques (BCTs), and engagement strategies in Vitalia.

Targeted Behavior	Game/Activity	Behavior Change Techniques (BCTs)	Engagement Strategy
Daily physical activity (light–moderate)	AR-guided stretching, core movement, jumping, walking	Action planning, prompts/cues, habit formation	Mirrored AR guidance, daily streaks, animated reinforcement
Intense physical activity (every other day)	AR mini-workouts: planks, push-ups, high-knees, jumping jacks	Graded task allocation, effort-based feedback, challenge framing	Avatar encouragement, unlockable rewards, timed sets
Nutritional literacy: food group awareness	“Food Pyramid” game (drag-drop foods into pyramid levels)	Categorization training, instruction on behavior	Visual scaffolding, progressive feedback, symbolic rewards
Nutritional literacy: anomaly detection	“Pick the Odd” game (select food that does not belong)	Discrimination learning, cognitive association	Fast visual tasks, reaction-based feedback, level completion, symbolic rewards
Nutritional literacy: dietary timing	“Select Meal” game (match foods with consumption time)	Implementation intentions, routine alignment	Contextual matching, reaction-based feedback, symbolic rewards
Nutritional literacy: food classification	“Food Matching” game (map items to broad food categories)	Knowledge reinforcement, pattern learning	Color-coded feedback, symbolic rewards
Self-regulated planning	“Build Your Week” nutrition planner (parent–child activity)	Joint goal setting, co-monitoring, social support	Icon-based, printable calendar, family-based monitoring
Narrative immersion	Story progression tied to task completion	Identity building, intrinsic motivation	Environment changes, animated cutscenes, mythic framing

To complement this granular mapping, Figure 3 offers a conceptual model of the hypothesized causal pathways underpinning Vitalia’s design. This model synthesizes key constructs from Self-Determination Theory (SDT), the COM-B model, and the Behavior Change Wheel, showing how the game’s narrative, mechanics, and rewards are expected to influence motivational mediators (e.g., autonomy, relatedness, competence) and behavioral outcomes (e.g., adherence, sustained engagement, and internalization of healthy habits). It provides an overview of how Vitalia’s formative elements aim to shape children’s behaviors and conceptual framing around health.

Figure 3. Conceptual model of the Vitalia intervention, illustrating the key behavioral, motivational, and design variables and their inter-relationships.

4. Technology Stack and Software Architecture

The implementation of Vitalia is grounded in a well-balanced technological architecture that prioritizes accessibility, performance, data privacy, and cross-platform compatibility. A core design objective was to ensure that the application could operate seamlessly on a wide range of devices, including entry-level tablets and smartphones, without requiring specialized hardware or software installations. To this end, the development team adopted a Web-based deployment strategy, leveraging widely supported browser technologies to avoid app store dependencies and enable instant user access. The web-based delivery was chosen for broader device compatibility, avoiding platform lock-in, and easing GDPR compliance in school or public deployments.

At the front-end, the application utilizes standard HTML5, CSS3, and JavaScript frameworks, supplemented by custom WebGL components for rendering AR overlays directly within the browser. This choice was driven by the need for cross-device support and minimal installation friction, particularly in educational environments with constrained IT resources. The use of WebGL enables real-time processing of camera input, ensuring smooth interaction between the physical and virtual elements during exercise-based mini-games.

The back-end infrastructure is implemented using Node.js and associated lightweight services, primarily to support user session handling, content updates, and statistical logging of anonymized interaction metrics. Crucially, no personal data are collected or stored. The system adheres strictly to GDPR compliance guidelines, using ephemeral data handling mechanisms that process camera input only in memory for the duration of gameplay. The architecture was designed to be stateless from the user’s perspective, ensuring high scalability and minimal server-side overhead.

AR functionality is achieved using MediaPipe Pose Landmarker, a state-of-the-art, on-device machine learning library developed by Google. It enables real-time human pose estimation by identifying 33 body landmarks through the device’s front-facing camera, without transmitting or storing any visual data. This ensures both immersive interaction and full compliance with privacy regulations. The application overlays animated guidance and interactive targets atop the user’s mirrored image, helping children complete physical exercises with visual and spatial support. Because all pose estimation runs locally, Vitalia remains performant and accessible even on entry-level smartphones and tablets.

Looking ahead, the architecture is modular and extensible, allowing for future enhancements such as more mini-games, more languages, expanded analytics for educational research, or the inclusion of intelligent recommendation engines. These additions, however, will be approached cautiously to preserve the current balance between personalization, data minimization, and ethical responsibility.

Altogether, the technological design of Vitalia reflects a careful integration of modern web technologies with privacy-first engineering. This foundation supports the app’s pedagogical goals while ensuring broad accessibility, rapid deployment, and safe engagement for young users in both home and school environments.

5. Discussion

Building on the pedagogical and system architecture previously described, this discussion reflects on the broader implications, design rationale, and behavioral foundations of Vitalia’s development within the DUSE project framework.

The DUSE initiative emerged in response to the pressing need for early, engaging interventions to counteract unhealthy habits in children, especially those linked to non-communicable diseases such as T2DM. Lasting changes in habits demands the transformation of children’s existing engagement patterns, particularly screen time, into immersive, self-reinforcing experiences that meaningfully incorporate healthy behaviors.

The entire architecture of Vitalia is grounded in behavioral change theory. It draws from the Habit Loop model [39], emphasizing cue–routine–reward cycles to foster repeated engagement, and from Self-Determination Theory (SDT) [5,6], promoting intrinsic motivation through autonomy, competence, and relatedness. These principles are integrated with insights from the COM-B model [20], which frames behavior as a function of capability, opportunity, and motivation, and has been effectively applied in the design of digital health interventions. Furthermore, the app reflects constructs from Social Cognitive Theory [21,22], particularly the role of observational learning and self-efficacy in behavior adoption and maintenance. Tasks in Vitalia are thus designed to be goal-oriented, meaningful, and scalable, allowing each child to advance at their own pace while developing lasting wellness practices.

Within this multi-model foundation, COM-B functions as the overarching system-level model that structures Vitalia’s behavior change logic. SDT and Social Cognitive Theory serve to shape the motivational and educational scaffolding, with an emphasis on autonomy-supportive, self-efficacious learning tasks. The Habit Loop model informs the daily engagement cycles and reinforcement rhythms. At the micro-design level, the Fogg Behavior Model (FBM) contributes to simplifying user actions through the interplay of motivation, ability, and triggers, while the Transtheoretical Model (TTM) inspires the staged progression of difficulty across tasks. This layered theoretical structure ensures both conceptual soundness, theoretical robustness, and operational diversity across game mechanics.

The app also aligns with the Behavior Change Wheel framework [20], ensuring that its gamified mechanisms target key drivers of change through structured prompts, rewards, and self-monitoring. The app adheres to rigorous data protection standards, refraining from collecting or storing any identifiable user data, and is aligned with the ethical and regulatory principles outlined in the DUSE project framework and broader EU guidance. Altogether, Vitalia exemplifies the DUSE project’s core ambition: to enable transformative, ethically grounded, and child-centric interventions for reshaping lifestyle behaviors through intelligent, immersive technology.

These theoretical insights shaped several key design constraints. Firstly, the app had to remain cognitively accessible to early learners while retaining motivational depth across time. Secondly, it had to adapt to diverse socio-familial contexts, accommodating both active parental involvement and primarily independent child use. These constraints informed the app’s modular structure, narrative scaffolding, and hybrid online–offline activity design. For example, real-life nutritional tasks like meal planning or the nutrition quests were prioritized to bridge digital engagement with everyday behaviors, reinforcing continuity of learning.

To sustain engagement, Vitalia leverages adaptive progression mechanics, an in-game mentor figure, and emotional feedback loops. The reward system, challenge-based learning structure, and interactive storytelling form a motivational triad, guiding players towards the adoption of consistent, positive habits. AR plays a pivotal role in this model. Through real-time overlays and visual feedback, AR fosters embodied interaction, enabling children to mirror movement and perform exercises at their own pace. Despite introducing technical and ethical complexities, AR was implemented with GDPR-compliant safeguards, ensuring privacy and intuitive usability.

While AR games like Pokémon GO (Niantic, Inc., Pokémon GO, online at https://pokemongo.com (accessed on 8 July 2025)) have shown motivational benefits for physical activity [40], they are not specifically tailored for the dietary–physical integration or age-specific interaction of Vitalia. Moreover, their use of commercial incentives or non-health narratives contrasts with Vitalia’s ethical, child-centric design.

Preliminary user testing with children aged 10–11 during pilot sessions provided anecdotal evidence of strong engagement with the visual and narrative elements of the app. User feedback informed subsequent updates to character expressions, color palettes, and voice acting pacing. While not yet formally assessed, these elements were iteratively refined in response to child reactions. The app’s real-world adaptability, permitting use even without parental mediation, and its balance of play, narrative, and evidence-based content, make it suitable for diverse family and school settings. Crucially, it avoids the common pitfall of top-down messaging, instead offering child-centered, participatory learning grounded in ethical foresight and developmental science. (See Figure 4).

Figure 4. Photos from the preliminary pilot demonstration and testing with the main target group.

This study did not involve the collection of identifiable human data nor medical interventions. All interactions through the Vitalia app were anonymous and non-invasive, falling under observational usage analytics.

While this paper presents the design and rationale of Vitalia the app is currently being prepared for large-scale longitudinal evaluation of behavioral outcomes, and integration with educational systems, within the goals of the DUSE project, advancing the project’s core ambition to reshape lifestyle behaviors through transformative, immersive, and ethically aligned digital interventions for children.

Vitalia’s conceptual design is informed by a rich body of behavioral and educational theory, but also responds to growing empirical insights about digital interventions in pediatric health. For example, the use of AR in embodied cognition has been shown to enhance memory retention and motor skill acquisition in younger populations [41], while goal-oriented game design aligns with habit formation strategies effective in managing lifestyle-related risk factors for T2DM [42]. By integrating multiple streams, cognitive–behavioral science, digital game theory, and health literacy education, Vitalia offers a comprehensive and scalable platform.

Compared to prior narrative-driven serious games such as “Escape from Diab” and “Nanoswarm”, which target older children through prolonged gameplay sessions and focus primarily on diet and exercise education, Vitalia introduces a novel mobile-first paradigm for habit reshaping in younger age groups. By embedding micro-interactions within an AR-enhanced fantasy narrative and aligning its mechanics with validated behavioral theories (SDT, COM-B, SCT, FBM, TTM), the app offers an engaging yet structured approach tailored to formative stages of childhood. In doing so, it addresses a largely unfilled niche in early-stage diabetes prevention through playful yet evidence-based digital intervention.

While Vitalia was designed with privacy, accessibility, and child safety in mind, certain limitations merit acknowledgment. These include potential screen time concerns, the need for adequate physical space for AR activities, and variability in AR performance on low-end devices. Additionally, user engagement may differ based on context (e.g., home vs. school) and adult involvement. These limitations will inform the design of future evaluation phases.

It is important to clarify that this paper presents the theoretical, pedagogical, and technical underpinnings of Vitalia, rather than a post hoc empirical evaluation. A longitudinal, mixed-methods assessment is underway involving educators, physical activity, and public health experts. This evaluation will collect evidence on children’s cognitive uptake, behavioral consistency, and emotional engagement. Future work will also consider physiological data in ethically approved contexts. Although the first testing pilot took place in Greece, the modular design and multilingual capabilities of Vitalia reflect its intended applicability across diverse socio-cultural and educational contexts, as required by any EU-wide project, like DUSE.

Table 2 summarizes the key gamified interventions referenced in this study. Compared to prior efforts, Vitalia uniquely combines mobile AR, multi-theoretical scaffolding, and daily micro-interventions tailored for children of primary education. Its dual focus on nutrition and physical activity, together with parent–child co-design elements, positions it as a distinctive contribution to early-stage diabetes prevention through playful learning.

Table 2. Comparative overview of referenced serious games and mobile health interventions.

System	Platform	Narrative	Core Focus	Key Innovation
Vitalia	Mobile AR	✓ (myth-based)	Physical activity, nutrition	Multilingual, modular AR mini-games, co-designed, multi-model BCT integration
Escape from Diab	Desktop PC	✓ (hero journey)	Diet, physical activity	Story-driven with SCT framing and experimental trials
Nanoswarm	Desktop PC	✓ (sci-fi narrative)	Diet, physical activity	Combines fantasy storyline with SCT, goal-setting, reinforcement
Squire’s Quest!	Desktop/Web	✓ (medieval quest)	Fruit and vegetable intake	Goal setting + parental involvement in planning
FitQuest	Mobile (AR)	✗	Physical activity	School-based AR motion tracking + personalized targets
Fooya!	Mobile	✗	Healthy eating (implicit)	Action reflex training via gamified responses to food enemies
Pokémon GO (adapted for studies)	Mobile AR	✓ (fantasy)	Movement, exploration	Location-based, community-driven motivation

6. Conclusions

The Vitalia mobile app represents a significant step in utilizing modern technological advancements, particularly gamification and augmented reality, to address critical public health challenges like childhood T2DM. By creating an engaging and immersive learning environment, Vitalia empowers children to take an active role in systematically reshaping their own habits towards healthier lifestyles.

While no formal user study with hypothesis testing was conducted at this stage, exploratory pilot sessions were carried out with small groups of children to collect behavioral traces, assess usability, and gather observational insights. These activities served as formative feedback loops during development, not as statistically conclusive evaluations. As this is the case, the primary contribution lies in demonstrating a structured and theoretically justified design of a novel educational health tool.

Future work will focus on longitudinal impact assessment, examining the sustained behavioral outcomes, biases in interaction patterns, and the scalability of the intervention in diverse educational settings. Additional pilot studies are planned across diverse contexts to assess scalability and adaptability. The approach sets the foundation for a new genre of ethical, educational, and impactful gamified health interventions tailored to the developmental needs of children. Furthermore, future comparisons with existing serious games in diabetes prevention can clarify the unique contribution and transferability of Vitalia’s integrated design.