Eating disorders (EDs) are complex psychopathological conditions characterized by abnormal eating habits and a distorted body image (BI), significantly affecting individuals’ physical health and psychosocial well-being. EDs include a broad spectrum of conditions, of which Anorexia Nervosa (AN), Bulimia Nervosa (BN) and Binge Eating Disorder (BED) are the primary types. AN is classified into two primary subtypes: the restrictive subtype, where individuals achieve extreme body weight through dieting, fasting, or excessive exercise; and the purging subtype, characterized by an unhealthy low body weight with episodes of binge eating followed by compensatory behaviors such as vomiting or the use of laxatives to prevent weight gain. BN is distinguished by recurrent episodes of binge eating accompanied by compensatory behaviors to counteract the effects of overeating and weight gain. In contrast, BED involves repeated episodes of binge eating without subsequent compensatory actions [1].

In Western countries, a substantial proportion of young women and men, up to 17.9%, meet the diagnostic criteria for an ED in early adulthood [2], and the number of diagnoses is dramatically increasing after Covid-19 [3]. What underscores these conditions as a mental health emergency is the increasing prevalence combined with the limited effectiveness of available prevention, assessment, and treatment procedures. This is partially linked to multifaceted factors that contributes to EDs etiology and maintenance.

EDs manifest primarily across two dimensions: behavioral and experiential. The behavioral domain encompasses the actions undertaken by individuals to exert control over their bodies, including, food elimination, food restriction, and episodes of binge eating. These behaviors are the visible manifestations of the disorder, observable and quantifiable. However, the complexity of EDs also reaches the experiential domain, namely the internal, subjective experiences of individuals with EDs. Specifically, the experiential domain includes the emotional, perceptual, and cognitive aspects that shape individuals’ relationships with food and their bodies, which in turn influence overall daily functioning.

On one side, EDs are characterized by profound food-related dysfunctional emotional reactions [4]. The fear of gaining weight, the anxiety or disgust triggered by certain foods in certain situations, and the guilt following eating are emblematic of the disordered relationship with food that characterizes EDs. This complex emotional experience significantly impacts the individual’s ability to maintain a healthy eating behavior, often leading to avoidance, restriction, compensatory or uncontrolled behaviors that further exacerbate the disorder.

On the other side, a critical and pervasive issue is BI distortion [5, 6], where individuals inaccurately perceive their bodies as larger or more flawed than reality and deeply link their self-esteem and self-worth to distorted BI. This distortion is deeply linked to a significant difficulty in developing a stable sense of self, exacerbated by a lack of coherent, first-person experience of their body [7]. Individuals with EDs often struggle to feel a direct, personal connection to their bodily sensations and emotions. Instead, they adopt an external, object-centered perspective (self-objectified) influenced by societal ideals and past observations [8].

Intriguingly, two separate longitudinal studies conducted over four years, each involving upwards of 2000 participants [9, 10] revealed that self-objectification held a significantly higher predictive value for both the remission and emergence of EDs when compared to other widely acknowledged factors - body dissatisfaction, thin-ideal internalization, negative affectivity and lower self-esteem - that demonstrated significant less predictive power. This suggests a potentially essential role for self-objectification in the progression and mitigation of EDs, meriting further investigation within the field.

Recently, the Allocentric Lock Hypothesis (ALH) proposed that EDs may arise from difficulties in multisensory body integration [11]. This integration process involves combining internal bodily signals (e.g. hunger, proprioception) with external sensory information (e.g. vision, touch) and autobiographical memories (e.g., remembering past experiences related to body image or eating, such as recalling past comments about one’s appearance or feeling shame during social eating situations) to form a coherent representation of one’s physical self [12].

According to predictive coding theories, the brain continuously generates and updates an internal model of the body and surroundings, allowing it to predict and integrate diverse sensory inputs through embodied simulations [13]. The ALH proposes that in EDs, there is a disruption in these predictive mechanisms underlying multisensory integration [11]. As a result, individuals with EDs become locked into an observer-based (allocentric) embodied simulation of their body [14, 15]. Negative experiences like teasing, objectification through social media exposure, or distorted autobiographical memories originally shape the allocentric perspective. This outdated model remains rigid, failing to update accurately despite contradictory information from current sensory inputs about the individual’s actual bodily state. This persistent allocentric representation can cause ongoing BI disturbances, leading to persistent dissatisfaction and shame. These experiences trigger anxiety and drive maladaptive behaviors aimed at controlling perceived bodily flaws based on memory rather than true corporeal reality.

In this context, a key advantage of Immersive Virtual Reality (IVR) for EDs is that it can simulate virtual bodies and the worlds around them that dynamically adjust to the user’s actions, providing predicted multisensory feedback just as the brain generates and updates internal body models to anticipate sensory inputs [16]. This is particularly supported by advanced IVR technologies, such as head-mounted displays (HMDs), that enable real-time interaction with the virtual world through motion tracking, hand controllers, and sensory feedback devices.This alignment makes IVR an unprecedented “playground” to directly apply principles of predictive coding.

Through carefully constructed virtual environments, it is possible a controlled delivery of challenging multimodal experiences (e.g., exposure to high-calorie food) that induce modest prediction errors in a safe, immersive manner [17]. For example, IVR can recreate triggering situations, such as mealtimes, in personalized environments, placing patients in a range of contexts from kitchens to restaurants, whether alone or with others, and presenting various types of food [18]. These environments have the potential to elicit patients’ authentic emotional reactions that allow clinicians to understand deeper the patient’s emotional difficulties and to work with them on managing the emotional responses.

Moreover, IVR allows the embodiment in bodies different from the actual one (e.g., full body illusions) providing disconfirming multisensory feedback, that create opportunities to update the internal body models of the user iteratively [19]. For example, by embodying virtual avatars that closely mirrors or subtly adjusts their physical form, users can experience a different perspective on their body size, shape, or appearance [20]. This “re-training” of the predictive mechanisms can foster more accurate modeling of reality with reduced predictive biases that contribute to ED psychopathology [21].

Initial review works have focused on outlining and summarizing the application of IVR in EDs [18, 22, 23], and preliminary studies suggest its efficacy in addressing core EDs symptoms [16]. These data suggest that IVR could be a supportive tool for clinical practice, as it can offer an alternative or an addition to available assessment and intervention approaches.

This scoping review aims to explore the current use of IVR technology across various aspects of eating disorders (EDs). This work moves beyond previous theoretical works, that either provided a general description of the techniques [23], or focused on specific techniques [20], specific EDs [18] or specific outcomes [24], aiming at providing a more updated and comprehensive representation of the field [22].

Specifically, it offers a detailed analysis of novel IVR methods in EDs assessment, understanding and treatment, evaluating their effectiveness across various disorders. Furthermore, it not only evaluates the effectiveness of IVR in key aspects of EDs, including body image distortion and food-related anxiety, but also discusses its integration with established treatments.