Healthy orthorexia vs orthorexia nervosa: associations with body appreciation, functionality appreciation, intuitive eating and embodiment

Current conceptualizations and measures of orthorexia nervosa may not be accurately distinguishing between the healthy vs pathological pursuit of a healthy diet, leading to very high prevalence rates and risking the pathologizing and stigmatizing of healthy eating more generally. Recent research has identified healthy orthorexia as a novel construct conceptually distinct from orthorexia nervosa, which represents the non-pathological pursuit of a healthy diet. In light of the strong body of evidence supporting the role of positive body image in eating behavior, the current study aimed to examine the associations between healthy orthorexia, orthorexia nervosa, intuitive eating and indices of positive body image. The current study employed a cross-sectional design. An online community sample (N = 835; 62% women; Mage = 40.24, SD = 14.45) completed self-report questionnaires including the Teruel Orthorexia Scale, Body Appreciation Scale-2, Functionality Appreciation Scale, Intuitive Eating Scale-2, and Experience of Embodiment Scale. Intuitive eating and indices of positive body image were significantly positively associated with healthy orthorexia and inversely associated with orthorexia nervosa. A hierarchical multiple regression analysis found that intuitive eating and indices of body image were uniquely associated with 13.3% of the variance of healthy orthorexia above and beyond that accounted for by orthorexia nervosa. Intuitive eating moderated the relationship between healthy orthorexia and orthorexia nervosa. The findings of this study provide support for intuitive eating and indices of positive body image as worthy of further exploration as important factors which distinguish between healthy orthorexia and orthorexia nervosa. V, descriptive study.


Introduction
Orthorexia nervosa is a term initially coined by Bratman [1] to describe the pursuit of healthy eating that intensifies and becomes an excessive, pathological preoccupation with consuming only foods that are "healthy" and avoiding those that are "unhealthy." Since, there has been much debate surrounding the conceptualization of orthorexia nervosa, and there remains no official consensus definition or diagnostic criteria to date [2][3][4][5][6]. Recent work has raised concerns about the over-diagnosis of orthorexia nervosa, risking the pathologizing and stigmatizing of followers of healthy diets, regardless of the presence of pathology [7][8][9]. For instance, as an eating disorder, orthorexia nervosa would be expected to have prevalence rates similar to other eating disorders, which are no higher than 2% [10]. However, the literature has documented prevalence estimates for orthorexia nervosa ranging up to 88.7% in non-clinical populations [3]. Additionally individuals who are vegan, vegetarian, or simply attempt to avoid processed foods are often being labeled as having orthorexia nervosa [7,8,[11][12][13]. This is concerning considering the extensive body of evidence supporting that a healthy diet can enhance physical and psychological wellbeing (see e.g., [14][15][16][17]).
The pathology-driven approach to the study of orthorexia nervosa has left unstudied the normal, flexible, health 1 3 promoting pursuit of a diet with a preference for healthy foods over unhealthy foods. Commonly used measures of orthorexia nervosa may not be accurately distinguishing between the pursuit of a healthy diet which is pathological and that which is not pathological [7,13,18,19]. Although various measures have been developed, [13,19], the Teruel Orthorexia Scale (TOS) [20] is perhaps the only measure which makes the distinction between the pursuit of a healthy diet which is beneficial (healthy orthorexia) and that which is pathological (orthorexia nervosa). Based on the TOS, both healthy orthorexia and orthorexia nervosa reflect eating behaviors in which an individual dichotomizes foods into "healthy" and "unhealthy" categories. Healthy orthorexia, however, is thought to reflect the pursuit of healthy foods in a way which is health enhancing and non-pathological, which is in line with Bratman's [7] argument that healthy diets can indeed be followed in the absence of pathology.
Studies using the TOS have found significant positive associations between the two constructs, providing support for healthy orthorexia and orthorexia nervosa having some conceptual overlap (i.e., both reflecting an interest in and the pursuit of a healthy diet) [20][21][22]. However, there is also increasing evidence supporting the two as conceptually distinct eating styles (i.e., with healthy orthorexia reflecting the healthy pursuit of a diet, and orthorexia nervosa reflecting the intensification of this pursuit into a disordered pathological obsession). Healthy orthorexia has been found to be positively associated with indices of wellbeing and inversely associated with negative affect, and orthorexia nervosa has been found to be inversely associated with indices of wellbeing and positively associated with indices of negative affect [20,21,23,24]. Additionally, it has been proposed that the motives that drive healthy orthorexia and orthorexia nervosa may differ with the former being driven by health-concerns, and the latter by weight control [23]. Recent work using the TOS to examine the typology of individuals based on orthorexic eating behaviors provides further support that healthy orthorexia diverges from orthorexia nervosa, with individuals with high healthy orthorexia and low orthorexia nervosa scoring higher on measures of self-esteem and intuitive eating, and those with low healthy orthorexia and high orthorexia nervosa scoring significantly higher on measures of anxiety, and depressive symptoms [22].
The surge in research on orthorexia nervosa has been paralleled by an increased interest in adaptive eating behaviors [25]. Perhaps the most researched is intuitive eating, which refers to a set of flexible eating behaviors that are regulated by internal physiological cues rather than external emotional and situational cues [26,27]. Individuals who eat intuitively trust and rely on their internal hunger and satiety cues to guide their eating behavior, avoid labelling foods as forbidden, eat for physical reasons rather than as a way of coping with emotional distress, and make food choices which support or enhance their body's functioning [28]. Intuitive eating has been found to be associated with lower levels of binge eating, drive for thinness, situational eating, emotional eating, food anxieties, food preoccupation and rigid dietary constraint [29][30][31][32][33][34][35][36][37]. Furthermore, there is a strong body of evidence to support that indices of positive body image, namely, body appreciation, functionality appreciation and embodiment, are psychological resources that enhance intuitive eating by promoting the awareness of, and appreciation for the functions of the body [38][39][40][41][42][43][44][45][46]. Additionally, enhancing embodiment is thought to promote adaptive eating styles by encouraging the awareness of internal physiological cues (e.g., hunger and satiety cues), which are relied on to guide eating behavior [47,48]. Intervention programs aimed at the treatment and prevention of a wide variety of eating disorders are increasingly focusing on the enhancement of intuitive eating and positive body image resources, with encouraging results [36,40,44,49].
Given the significant body of work supporting strong links between constructs of positive body image and eating behaviors, it is unsurprising that researchers are beginning to show interest in the relationships between these constructs and orthorexia nervosa. However, these studies are few, and have had mixed findings, providing evidence for both positive [50] and negative associations [51,52] between orthorexia nervosa and indices of positive body image. In addition, most of these studies used questionnaires that may have classed both the pathological and non-pathological pursuit of a healthy diet as orthorexia nervosa [9]. To the best of our knowledge, only one study has used the TOS to examine the links between healthy orthorexia and intuitive eating which found that individuals with higher healthy orthorexia and lower orthorexia nervosa are more likely to eat intuitively than those with lower healthy orthorexia and higher orthorexia nervosa [22].

The present study
In light of the commentary above, the conceptualization of healthy orthorexia offered by Barrada and Roncero [20] offers researchers a promising new avenue for exploring the pursuit of a healthy diet which is not pathological, and for differentiating this way of eating from orthorexia nervosa. Furthermore, intuitive eating, body appreciation, functionality appreciation and embodiment are constructs which seem to play an important role in promoting eating behaviors that are adaptive and health enhancing, and reducing those which are pathological [36,40,44,49]. Exploring the associations between these constructs in relation to healthy orthorexia and orthorexia nervosa could therefore ascertain whether healthy orthorexia uniquely is associated with more internally-driven, adaptive eating behaviors in comparison 1 3 to orthorexia nervosa, and therefore identify whether these constructs are worthy of further exploration as possible protective factors against the non-pathological pursuit of a diet progressing into orthorexia nervosa.
With this in mind, the present study aimed to explore the associations between healthy orthorexia, orthorexia nervosa, intuitive eating and constructs of positive body image (body appreciation, functionality appreciation and embodiment). Based on previous findings [20,21,24], we hypothesized that healthy orthorexia would be positively associated with orthorexia nervosa, and that intuitive eating and indices of positive body image would be positively associated with healthy orthorexia, and inversely associated with orthorexia nervosa. Furthermore, since healthy orthorexia is proposed as an eating behavior which is distinct from orthorexia nervosa in that it is non-pathological and is positively associated with enhanced health and wellbeing [20,21], we hypothesized that intuitive eating and indices of positive body image would be uniquely associated with healthy orthorexia after controlling for the contribution made by orthorexia nervosa. Finally, in light of the evidence supporting intuitive eating and indices of positive body image as promoting adaptive eating behaviors and reducing pathological eating behaviors [36,40,44,49], we hypothesized that the relationship between healthy orthorexia and orthorexia nervosa would be moderated by intuitive eating and indices of positive body image.

Method
This study employed an observational, cross-sectional design, using self-report measures.

Measures
The following measures were administered to all participants. All measures administered were in the English language.

Demographics
All participants were asked to provide their age, gender, height, weight, ethnicity, and socio-economic status. Body mass index (BMI) was calculated using height and weight as kg/m 2 .

Healthy orthorexia and orthorexia nervosa
The Teruel Orthorexia Scale (TOS) [20] comprises 17 items and two subscales that measure two dimensions of orthorexic eating behavior; Orthorexia Nervosa (ON) and Healthy Orthorexia (HO). Items are scored on a 4-point scale ranging from 0 = strongly disagree to 3 = strongly agree. The TOS shows good internal consistency for both subscales; ON (α = .81-.90), and HO (α = .80-.87), and re-test reliability over 18 months, with r > .70 [20]. Both subscales demonstrated good internal consistency for the present sample with alpha values of .83 for ON, and .84 for HO.

Body appreciation
The 10-item Body Appreciation Scale-2 (BAS-2) [45] measures acceptance of one's body, protection of one's body from unrealistic beauty standards, and respect and care for one's body. Items are rated on a 5-point scale ranging from 1 = never to 5 = always. The measure has favorable psychometric properties, conforming to a unidimensional structure with strong internal consistency (α = .93-.96), and test-retest reliability over a 3-week period (r = .90) [45]. Cronbach's alpha for the current sample was .95, demonstrating excellent internal consistency.

Functionality appreciation
The Functionality Appreciation Scale (FAS) [53] comprises 7 items that assess one's appreciation and respect for their body for the functions it is capable of performing. Items are rated on a 5-point scale ranging from 1 = strongly disagree to 5 = strongly agree. Psychometric testing of the FAS using exploratory factor analysis in a U.S. adult sample [53] has shown the measure to have adequate internal consistency (α = .86-.91), and test-retest reliability over a 3-week period (r = .81 for women, and r = .74 for men). The FAS demonstrated excellent internal consistency for the current sample (α = .90).

Intuitive eating
The Intuitive Eating Scale-2 (IES-2) [28] contains 23 items and four subscales, which assess the four dimensions of intuitive eating; Unconditional Permission to Eat (i.e., an individual's willingness to eat when hungry and a refusal to label certain foods as forbidden; 6 items), Eating for Physical rather than Emotional Reasons (i.e., eating when one is physically hungry rather than to cope with emotional distress; 8 items), Reliance on Hunger and Satiety Cues (i.e., an individual's trust in their internal hunger and satiety cues and reliance on these cues to guide eating behaviors; 6 items), and Body-Food Choice Congruence (i.e., a tendency to make food choices that honour one's health and body functioning; 3 items). Items are rated on a 5-point scale ranging from 1 = strongly disagree to 5 = strongly agree. The IES-2 has favorable psychometric 1 3 properties, demonstrating internal consistency for women (α = .87) and men (α = .89) [28], and 3-week test-retest reliability for both women (r = .99) and men (r = .82). For the current sample, the scale was found to be internally consistent; α = .87.

Embodiment
The 34-item Experience of Embodiment Scale (EES) [54] captures the experience of embodiment, which has been defined as the "lived experience of engagement of the body with the world" [54]. The measure comprises six subscales: Positive Body Connection And Comfort (i.e., positive emotions and connection towards the body; 6 items), Body Unencumbered Adjustment (i.e., the degree to which one feels discomfort in their body when engaging with the world in a way which hinders their adjustment; 8 items), Agency and Functionality (i.e., experiences of agency and functionality in the world; 7 items), Experience and Expression of Sexual Desire (i.e., comfort and self-attunement with expressing desire; 4 items), Attuned Self-Care (i.e., the attuned responsiveness to the body's physical and other needs; 6 items), and Resisting Objectification (i.e., resisting treating and living the body as an object; 3 items). Items are rated on a 5-point scale ranging from 1 = strongly disagree to 5 = strongly agree. The EES has demonstrated favorable internal consistency in samples of adult women, both for the total scale (α = .94) and for each of the subscales (α = .71-.90) [54], and test-retest reliability over a 3-month period (r = .93). The EES demonstrated excellent internal consistency for the current sample (α = .93).

Participants and procedure
After receiving ethical approval, an online questionnaire was generated using Qualtrics XM (www. qualt rics. com). Data were collected between November 2021 and February 2022. The study used a convenience sample with participants recruited via advertisements placed on social media websites, supplemented through the use of a snowball sampling method. The study was advertised as a study about "eating behaviors and body image", and all participants were provided with further information regarding the study requirements. Participants were limited to those over 18 years of age. Participation was anonymous, voluntary and without remuneration. All participants were asked to provide digital informed consent before completing the online questionnaire with the measures listed above, presented in a prerandomized order (automatically generated by Qualtrics) to control for order effects, and attention checks were placed at two points in the questionnaire. Qualtrics was configured to only record complete responses.

Data analysis
Prior to the analysis, a multilayer screening method was employed to ensure data quality based on recommendations for using online samples for eating disorder research [55,56], in which Internet Protocol (IP) addresses were checked to ensure that no participant answered the questionnaire more than once, response times were checked to identify any responses that were completed in under seven minutes, age, height and weight responses were checked improbable/nonsensical values, and any failed attention checks were identified. These checks identified two participants who entered nonsensical height/weight values, and six participants who failed attention checks, who were subsequently removed from the initial sample of N = 850, reducing the sample to N = 842.
The data analysis was carried out using SPSS version 28 (IBM SPSS Inc., Chicago, Illinois, USA). Missing data were managed using listwise deletion. Data were first examined for normality, linearity and homoscedasticity. Seven outliers were identified and removed using Mahalanobi's distance leaving a final sample of N = 835. A moderate positive skew was uncovered for BMI; no other substantial violations were identified. A log transformation was carried out on BMI, which resulted in it being normally distributed (skewness = 0.64 and kurtosis = 0.92). Following this, descriptive statistical analyses were carried out to examine the demographic characteristics of the sample.
A Pearson's product moment correlation analysis was used to examine the intercorrelations of the study variables, with r values of ≤ .10 being considered to have a small effect, ~ .30, a moderate effect, and ~ .50, a strong effect (based on Cohen [57]). Following this, a hierarchical multiple linear regression analysis was conducted to assess whether; (a) intuitive eating and positive body image indices were associated with a unique variance of healthy orthorexia after controlling for orthorexia nervosa, and (b) intuitive eating and indices of positive body image moderated the association between healthy orthorexia and orthorexia nervosa. A four-step analysis was performed, with healthy orthorexia as the criterion variable; age, BMI and gender were entered at step 1 as control variables, orthorexia nervosa was entered at step 2, intuitive eating and the indices of positive body image (body appreciation, functionality appreciation and embodiment) were entered at step 3, and interaction terms between orthorexia nervosa and intuitive eating, body appreciation, functionality appreciation and embodiment were entered at step 4. A statistically significant increment in R 2 at step 3 would indicate unique associations of intuitive eating and indices of positive body image over and above orthorexia nervosa, and a statistically significant increment in R 2 at step 4 would indicate the unique contribution of interaction effects. The p value was set at .01 in order to control for Type I error. All variables were centered at the mean, with the exception of gender, which was coded as 0 = male and 1 = female. The interaction terms were calculated from the centered variables. Hayes' PROCESS macro was used to examine any significant interactions, and simple slopes (at one SD above and one SD below the mean) were generated.

Demographic characteristics
The

Intercorrelations
As can be seen in Table 1, Pearson correlation coefficients indicate a significant positive association between healthy orthorexia and orthorexia nervosa, with a moderate effect size. In addition, intuitive eating and all indices of positive body image were significantly positively associated with healthy orthorexia, with small effect sizes. Conversely, intuitive eating and all indices of positive body image were inversely associated with orthorexia nervosa, and had small to moderate effect sizes.

Associations between study variables
The final model for the hierarchical multiple regression analysis was significant, as shown in Table 2. Results of step 2 showed that orthorexia nervosa was associated with 23% of the variance of healthy orthorexia, F(4, 830) = 67.78, p < .001, R 2 adj = .24, ΔR 2 = .23, after controlling for gender, age and BMI (f 2 = 0.30). Adding intuitive eating and the indices of positive body image at step 3 accounted for an additional 13% of the variance of healthy orthorexia, F(8, 830) = 63.32, p < .001, R 2 adj = .39, ΔR 2 = .13, f 2 = 0.15. The interaction terms added at step 4 were associated with an additional 2% of the variance of healthy orthorexia, F(12, 830) = 45.65, p < .001, R 2 adj = .39, ΔR 2 = .02, f 2 = 0.02. In the final model, orthorexia nervosa, functionality appreciation and intuitive eating were independently and uniquely associated with healthy orthorexia, with intuitive eating having the second strongest association (after orthorexia nervosa). A significant interaction effect was observed for orthorexia nervosa and intuitive eating, but not for any of the other interaction terms.

Moderation effects
A moderation model was computed to better examine how intuitive eating moderates the relationship between orthorexia nervosa and healthy orthorexia (see Fig. 1). The input variable was orthorexia nervosa, the outcome variable was healthy orthorexia, and the moderator was intuitive eating. Gender, age and BMI, as well as the other variables not tested in the moderation model were entered as covariates. The conditional effect was significant for those with high (B = 0.83, t = 18.32, p = .000), medium (B = 0.68, t = 19.87,

Discussion
Recent work has identified healthy orthorexia as a construct distinct from orthorexia nervosa, representing the non-pathological pursuit of a healthy diet [20]. To our knowledge, no study has explored the relationships between intuitive eating, indices of positive body image, healthy orthorexia and orthorexia nervosa using the TOS.
To address this gap in the literature, the current study aimed to examine the associations between healthy orthorexia, orthorexia nervosa, intuitive eating, body appreciation, functionality appreciation and embodiment. Overall our results provide new insight into indices of positive body image that might be important to consider in future research on orthorexic eating behavior. Consistent with previous research [20][21][22], healthy orthorexia and orthorexia nervosa were significantly positively correlated and orthorexia nervosa was significantly associated with 23% of the variance of healthy orthorexia. In addition, intuitive eating, body appreciation, body functionality and embodiment were all positively associated with healthy orthorexia and negatively associated with orthorexia nervosa, which is consistent with those of a handful of other studies that have examined similar associations of healthy orthorexia and orthorexia nervosa with other indices of wellbeing [20,21,23,24]. Together these findings provide further support for healthy orthorexia and orthorexia as two conceptually overlapping yet distinct eating styles; both reflecting the pursuit elements of dietary restraint (i.e., the pursuit of "healthy" foods and the avoidance of "unhealthy" foods) with the former being associated with indices wellbeing, and the latter with pathology [20][21][22]. This is also in line with previous findings which support that while healthy orthorexia and orthorexia nervosa can be associated in some individuals (i.e., having both healthy and pathological behaviors in relation to the pursuit of a healthy diet), it is also possible to have high levels of healthy orthorexia and low levels of orthorexia nervosa and vice-versa [22].
It is important to note that our findings stand in contrast to those of He et al. [50], who found positive associations between indices of positive body image and orthorexia nervosa. One way of explaining this discrepancy is by considering that the instrument used in He et al.'s study may have identified healthy orthorexia behaviors and not orthorexia nervosa. Our findings are in line with other work using the TOS, which identified higher levels of intuitive eating in individuals with high levels of healthy orthorexia and low levels of orthorexia nervosa [18]. The Step 1 Step 2 Step 3 Step 4 Variable Intuitive eating and indices of positive body image were found to be uniquely associated with healthy orthorexia after the association with orthorexia nervosa was accounted for. This finding suggests that healthy orthorexia is more than just the absence of the pathological aspects of orthorexia nervosa, in that it is uniquely associated with factors that are closely related to enhanced wellbeing and adaptive eating behaviors. This finding is in line with previous work which supports healthy orthorexia as distinct from orthorexia nervosa [21,22]. More specifically, functionality appreciation and intuitive eating were uniquely associated with healthy orthorexia, whereas body appreciation and embodiment were not. Functionality appreciation and intuitive eating share a common emphasis on the functions of the body; trusting and attending to the body's cues as a sign of what it requires [44]. Therefore, our findings suggest individuals who pay more attention to their bodily functions have higher levels of healthy orthorexia. These findings are in line with Depa et al.'s [23] argument that healthy orthorexia is motivated by the drive for health and wellbeing, in that a focus on enhancing health and wellbeing inevitably involves a closer attention to bodily functioning. An individual who follows a healthy diet due to health and weight concerns; however, is more likely to focus on their appearance and therefore also more likely to ignore the body's cues in favor of changing/ maintaining this. Based on these findings it seems worthwhile to further explore the relationships between different constructs of body image and orthorexic eating behaviors. Such research may provide further insights into the motives that underlie these behaviors.
Intuitive eating was the only factor found to have a significant moderation effect on the relationship between healthy orthorexia and orthorexia nervosa. Closer examination of this interaction revealed that higher levels of intuitive eating are associated with higher levels of healthy orthorexia in relation to orthorexia nervosa. Based on these findings seems that maintaining flexibility when it comes to following food rules is important in maintaining a healthy relationship with diet. Even though the effect size of the interaction was small (ΔR 2 = .02), these findings suggest that intuitive eating could be an important factor worthy of further exploration in this context. Given the substantial body of evidence supporting body appreciation, functionality appreciation and embodiment as playing an important role in protecting against the development of eating disorders, [36,40,44,49], it is surprising that these did not emerge as significant moderators. These findings might be explained by considering the acceptance model of intuitive eating [58], which identified body appreciation and functionality appreciation as constructs which promote intuitive eating. Similarly, positive embodiment is thought to promote adaptive eating behaviors including responsiveness to hunger cues and eating for physical reasons, which are important components of intuitive eating. [48]. Based on these findings, it is possible that body appreciation, functionality appreciation and embodiment

Strength and limitations
This study benefitted from several strengths. To the best of our knowledge, it was the first study to explore these indices of positive body image using the TOS [20]. In addition, the sample size was large, and all of the measures used in the study were psychometrically robust. However, our findings should be considered in light of various limitations. The use of an online convenience sample makes it inaccurate to claim that the sample is representative of the broader population. In addition, the correlational nature of the study is also somewhat limiting and does not allow for causal conclusions to be drawn. For instance, the relationships between the variables used in this study may be bi-directional and complex. In addition, this study did not provide insight into associations with latent factors of intuitive eating and embodiment. Similarly, although the variables used in this study were chosen based on a comprehensive literature review, there may be other constructs which play an important role in orthorexic eating behaviors which were not included here.
Finally, it is important to note that although overall our findings provide support for healthy orthorexia as distinct from orthorexia nervosa, they provide no insight into how orthorexia nervosa develops over time; i.e., is healthy orthorexia the non-pathological precursor to orthorexia nervosa as described by Bratman [7] in his conceptualization? Likewise, our findings do not provide insight into the role of positive body image and intuitive eating in the development of orthorexia nervosa. Prospective studies are needed to better understand the trajectory of orthorexia nervosa, as well as the role that positive body image and intuitive eating plays in this.

What is already known on this subject?
To date, research on the conceptualization and classification of orthorexia nervosa has primarily taken a pathologydriven approach. While such research has been vital to our understanding of orthorexia nervosa, researchers have noted that it has posed the risk of pathologizing and stigmatizing healthy eating more generally. Recent work has identified healthy orthorexia as an eating behavior that is conceptually distinct from orthorexia nervosa, which represents the nonpathological pursuit of a healthy diet. This conceptualization offers researchers a promising new avenue to explore factors that distinguish the non-pathological pursuit of a healthy diet from orthorexia nervosa, which may act as protective factors.

What this study adds?
This study makes a unique contribution to the literature by identifying unique associations between intuitive eating, indices of positive body image and healthy orthorexia, as compared to orthorexia nervosa. These findings provide support for intuitive eating, body appreciation, functionality appreciation and embodiment as worthy of further exploration as potentially important factors that distinguish between healthy orthorexia and orthorexia nervosa. Further exploring these relationships using appropriate measures and longitudinal designs could prove worthwhile in guiding appropriate intervention aimed at averting or attenuating the adverse impact of orthorexic eating behavior.