Assessment of Intuitive Eating and Mindful Eating among Higher Education Students: A Systematic Review

Background: The role of mindful eating (ME) and intuitive eating (IE) in improving eating behavior, diet quality, and health is an area of increasing interest. Objective: The objective of this review was to identify the instruments used to assess ME and IE among higher education students and outcomes related to these dimensions. Methods: This review was carried out according to the PRISMA statement, through systematic searches in PubMed, Web of Science, PsycInfo, and Scopus. The inclusion criteria selected for higher education students, levels of ME and/or IE reported, and observational and clinical studies. The exclusion criteria selected against reviews, qualitative studies, and case studies. Quality was assessed using the Academy of Nutrition and Dietetics Quality Criteria Checklist. Results: A total of 516 initial records were identified, from which 75 were included. Cross-sectional studies were the most common research design (86.7%). Most studies were conducted with samples that were predominantly female (90.7%), White (76.0%), aged 18 to 22 years (88.4%), with BMI < 25 kg/m2 (83.0%), and in the United States (61.3%). The Intuitive Eating Scale (IES), the Mindful Eating Questionnaire (MEQ), and their different versions were the most used instruments. The outcomes most studies included were eating behavior and disorders (77.3%), anthropometric assessments (47.8%), mental health (42.0%), and body image (40.6%). Regarding the quality of studies, 34.7% of studies were assigned a positive, 1.3% a negative, and 64.0% a neutral rate. Conclusions: IES and MEQ were the most used instruments. RCT and cohort studies are scarce, and future research with a higher level of quality is needed, especially on the topics of food consumption, diet quality, and biochemical markers.


Introduction
In recent years, mindful eating (ME) and intuitive eating (IE) as psychological function approaches have not only received considerable research interest but have also been frequently applied in clinical contexts to address problematic eating behaviors and the challenges many face in controlling their food intake [1][2][3].The practices of ME and IE have also been used to influence energy intake or diet quality, but the evidence is still insufficient to draw strong conclusions about their effects on food consumption [4] and on weight management [5,6].
ME arose in the context of the investigation of mindfulness-based interventions initiated by Jon Kabat-Zinn (1982) [7] in the late 1970s.It corresponds to the enjoyment of food utilizing all the senses, without judgment, listening to internal cues of the body (i.e., hunger and satiety) to avoid overconsumption, and utilizing external cues (reducing portion sizes and distractions while eating, and eating slowly) to assist in achieving awareness [8].The first studies on ME began in the 1990s, in the context of binge eating [2], and since then, different measurement scales of ME scores have been developed [9].IE is a style of eating that focuses on eating motivated by physical reasons, being characterized by eating based on physiological hunger and satiety cues rather than situational and emotional cues, and it is associated with psychological well-being [10].The first IE measurement scales appeared in the 2000s, and since 2006, Tylka et al. [10,11] have been deepening the study of its psychometric properties and improving the Intuitive Eating Scale.
Entering university can be a moment in life marked by great social pressure, with situations and challenges that increase the levels of stress, anxiety, and depressive symptoms [12], contributing to an increased risk of dysregulation of eating and worsening of eating behaviors [13] and body image perception, leaving university students more vulnerable to eating disorders [14].In this context, ME and IE are useful approaches to promote improvements in eating and mental health by helping students to focus on their own cues of hunger and satiety, rather than following fashion trends or giving in to social pressure [15,16].
Most recent studies confirm that eating disorders are highly prevalent worldwide, especially in women [17], and the burden of eating disorders peaks at 25 to 29 years for females and 30 to 34 years for males [18].In addition, authors point out that the pandemic has brought new challenges and obstacles for those who have a problematic relationship with food [19].During the pandemic, the incidence of a first diagnosis of an eating disorder increased with an overall excess of 15.3% compared with the previous year and was greater in adolescents aged between 10 and 19 years old [20].
In view of this, there is a growing interest in the study of approaches focused on eating behavior and the dimensions of eating behavior, especially ME and IE.This systematic review examines the evidence from primary studies that evaluated ME and IE with the aims (1) to describe the scales used to measure ME and IE in college students and (2) to identify the outcomes related to ME and IE.

Materials and Methods
This systematic review was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines [21].The protocol of this review was registered in PROSPERO (registration number CRD42022358570).This review investigates the following question: Which instruments have been used to measure mindful eating and intuitive eating among higher education students?

Search Strategy
Searches for peer-reviewed journal articles were performed in Scopus, Web of Science, PsycInfo, and MEDLINE/PubMed.There were no restrictions on language or year of publication.The databases were searched using key phrases and Boolean operators that were established based on the PICO (Problem, Intervention, Comparison, and Outcome) criteria (Table 1).Web of Science, Scopus, PsycInfo, and Pubmed were searched up to 3 November 2023.The literature search was performed using the following terms without restrictions ("intuitive eating" OR "mindful eating" OR (mindfulness AND (eating OR food OR diet*))) AND ("higher education students" OR "university students" OR "college students").The reference lists of selected studies were hand-searched, and additional references were included if relevant and if not retrieved by the initial database searches.

Inclusion and Exclusion Criteria
The following inclusion criteria were used: studies with higher education students of one or both sexes; studies that evaluated the levels of ME and/or IE; observational (cohort, cross-sectional, and case-control studies) and clinical studies.Systematic reviews, meta-analyses, literature reviews, qualitative studies, and case studies were excluded.All studies presenting original empirical results and meeting the other eligibility criteria were included in the review.

Study Selection
The study selection process was performed independently by two reviewers (F.R. and R.P.) using EndNote20 reference management software.Duplicate studies were removed.Title and abstract screening, followed by full-text screening, was performed against the eligibility criteria.The two review authors independently screened the titles and abstracts of the articles identified in the searches.Full texts were obtained for all studies considered eligible for inclusion from this process or for which eligibility was unclear.The two review authors independently decided on which studies to include or exclude.Any disagreements were resolved by discussion, and if consensus was not reached, another review author (B.O.) not involved in the search process was consulted and a decision made.Reasons for exclusion were noted by each author, discussed, decided upon as a group, and recorded in the PRISMA flow diagram (Figure 1).

Inclusion and Exclusion Criteria
The following inclusion criteria were used: studies with higher education students of one or both sexes; studies that evaluated the levels of ME and/or IE; observational (cohort, cross-sectional, and case-control studies) and clinical studies.Systematic reviews, metaanalyses, literature reviews, qualitative studies, and case studies were excluded.All studies presenting original empirical results and meeting the other eligibility criteria were included in the review.

Study Selection
The study selection process was performed independently by two reviewers (F.R. and R.P.) using EndNote20 reference management software.Duplicate studies were removed.Title and abstract screening, followed by full-text screening, was performed against the eligibility criteria.The two review authors independently screened the titles and abstracts of the articles identified in the searches.Full texts were obtained for all studies considered eligible for inclusion from this process or for which eligibility was unclear.The two review authors independently decided on which studies to include or exclude.Any disagreements were resolved by discussion, and if consensus was not reached, another review author (B.O.) not involved in the search process was consulted and a decision made.Reasons for exclusion were noted by each author, discussed, decided upon as a group, and recorded in the PRISMA flow diagram (Figure 1).

Data Extraction
Two of the review authors independently extracted data using a standard data extraction form developed by the review authors for the purpose of this review according to the PICO model.
The following data from each included study were extracted:

Data Extraction
Two of the review authors independently extracted data using a standard data extraction form developed by the review authors for the purpose of this review according to the PICO model.
The following data from each included study were extracted: (1) general: authors, year of publication, country; (2) study design; (3) sample characteristics: size, sex, age, ethnicity, body mass index (BMI); (4) ME and IE measurement scales; (5) outcomes associated to ME and IE.

Quality Assessment
Quality was assessed using the Academy of Nutrition and Dietetics Quality Criteria Checklist: Primary Research tool [22].This tool consists of a questionnaire to evaluate the validity of 10 study-related items: (1) research question, (2) selection of participants, (3) comparability of study groups, (4) handling of withdrawals, (5) blinding, (6) adequate intervention detail, (7) outcome reliability, (8) appropriateness of statistical analysis, (9) conclusion accuracy, and (10) bias from funding or sponsorship.Studies were assigned a positive rating (if positive for items 2, 3, 6, and 7 and for at least one additional item), negative rating (if negative for 6 or more items), or neutral rating (if items 2, 3, 6 and 7 indicated that the study was not exceptionally strong).

Data Synthesis
Study data were explored according to the PICO strategy, and for each study included in this review, the following were described: the sociodemographic profile (sex, age, ethnicity) and BMI (mean, SD, and BMI categories) of higher education students.In addition, factors associated with ME and IE were described, divided into the following categories: eating behavior(s) and eating disorders; food intake and diet quality; BMI and other anthropometric or body composition assessments; body image; mindfulness; selfcompassion; physical activity; quality of life and mental health; and biochemical markers.

Study Selection
A total of 387 studies resulted from searches of the following: PubMed (n = 122), Scopus (n = 124), Web of Science (n = 141), PsycInfo (n = 106), and records identified in other sources (n = 23).After the removal of duplicates, 275 studies were examined for title and abstract screening; 102 study reports remained for full-text screening; and 75 studies met the final criteria for inclusion in the review.An overview of the study selection process is shown in Figure 1.The extraction of the main information from the studies is presented in chronological order (Table 2).The proportions calculated during data extraction from the studies were obtained considering the total number of studies included in the review (n = 75).

Study Design and Quality
The publication of the studies occurred predominantly in the last decade (2014 to 2023) (n = 61, 81.3%) (Figure 2).Of the 75 studies included in the final review, 65 (86.7%) were cross-sectional, 6 (8%) were randomized clinical trials (RCT), 3 (4%) were quasiexperimental, and 1 (1.3%) was a randomized quantitative crossover study.The duration of RCT interventions ranged from 1 to 16 weeks, including follow-up time after the intervention.The numbers of participants in individual studies ranged from 14 to 2133; from the 75 studies, 68 (90.7%) had samples with a higher proportion of women, and 20 (26.6%) were conducted exclusively with female participants.In most studies (n = 61, 88.4%), the age of the participants was between 18 and 22 years old (based on the mean, median, or frequencies).Among the studies that assessed BMI (53 out of 75; 70.6%), in most of them (n = 44, 83.0%), the mean BMI was below 25 kg/m 2 , and the BMI ranged between 13.3 and 59.06.In none of the studies was the average greater than 30 kg/m 2 .Among the studies that described ethnicity (50 of 75; 66.6%), in most of them (n = 38, 76%), more than half of the sample of participants was White.

ME and IE Measurement
Among the studies that measured IE (n = 51), the IES proposed by Tylka (2006) [10] and its different versions were the more frequently used scales (n = 46, 90.2%).Among the studies that measured ME (n = 27), MEQ [34] and its different versions were used in approximately Upon evaluation per the Academy of Nutrition and Dietetics Quality Criteria Checklist, 34.7% (n = 26) studies were assigned a positive rating, 1.3% (n = 1) a negative rating, and 64% (n = 48) a neutral rating.
The numbers of participants in individual studies ranged from 14 to 2133; from the 75 studies, 68 (90.7%) had samples with a higher proportion of women, and 20 (26.6%) were conducted exclusively with female participants.In most studies (n = 61, 88.4%), the age of the participants was between 18 and 22 years old (based on the mean, median, or frequencies).Among the studies that assessed BMI (53 out of 75; 70.6%), in most of them (n = 44, 83.0%), the mean BMI was below 25 kg/m 2 , and the BMI ranged between 13.3 and 59.06.In none of the studies was the average greater than 30 kg/m 2 .Among the studies that described ethnicity (50 of 75; 66.6%), in most of them (n = 38, 76%), more than half of the sample of participants was White.

ME and IE Measurement
Among the studies that measured IE (n = 51), the IES proposed by Tylka (2006) [10] and its different versions were the more frequently used scales (n = 46, 90.2%).Among the studies that measured ME (n = 27), MEQ [34] and its different versions were used in approximately two-thirds (n = 17, 62.9%) (Table 3).Of the total collection of studies, four used IES-2 subscales and one used an MEQ subscale (Table 2).* Three studies evaluated both intuitive eating and mindful eating.

Discussion
In this systematic review, the objective was to analyze the state of the art of research on ME and IE among higher education students.It was found that the studies predominantly involved young, female, and White participants, with average BMI values in the normal weight category.Furthermore, it was observed that although research on ME and IE has been ongoing for over two decades, the increase in the number of publications has been more significant in the last 10 years.
ME and IE are two important concepts in the field of nutrition, health, and eating behavior that can be particularly relevant for higher education students who are in a transitional phase from adolescence to adulthood, with significant demands for adaptation in their routines, including eating habits, new responsibilities, new relationships, and academic activities that require time, concentration, and performance evaluation [99,100].These factors can influence eating behavior and patterns and require greater attentional and emotional regulation [101,102].
Although the fundamental principles of ME and IE are universal and can be applied in any culture or context, the cultural context can affect how people perceive and practice ME and IE.This systematic review found that most studies focused on North America, especially the United States, which has been a major country in ME and IE research.However, these concepts have also been studied in other countries, including Turkey, Canada, United Kingdom, Japan, and others.In countries like Japan, researchers have proposed ME scales with expanded dimensions to encompass aspects such as health promotion and sustainability [65].Given the cultural and social differences, it is important for researchers to be aware of the necessary adaptations for different cultural contexts, in terms of both measurement scales and intervention protocols.
Based on the studies analyzed in this review, it was found that the scales most frequently used for measuring IE were the Intuitive Eating Scale [10] and its different versions, and those for measuring ME were the Mindful Eating Questionnaire [34] and its different versions.Studies on the psychometric properties of the IE scales have been more consistent and systematic for the IES [10,11], which is based on four constructs: Body-Food Congruence, Eating for Physical Reasons and not Emotional Reasons, Reliance on Hunger and Satiety Cues, and Unconditional Permission to Eat.On the other hand, the scales for ME have important differences in their conceptual bases and psychometric properties.One factor that has likely contributed to this is the lack of a clear definition of ME.

Discussion
In this systematic review, the objective was to analyze the state of the art of research on ME and IE among higher education students.It was found that the studies predominantly involved young, female, and White participants, with average BMI values in the normal weight category.Furthermore, it was observed that although research on ME and IE has been ongoing for over two decades, the increase in the number of publications has been more significant in the last 10 years.
ME and IE are two important concepts in the field of nutrition, health, and eating behavior that can be particularly relevant for higher education students who are in a transitional phase from adolescence to adulthood, with significant demands for adaptation in their routines, including eating habits, new responsibilities, new relationships, and academic activities that require time, concentration, and performance evaluation [99,100].These factors can influence eating behavior and patterns and require greater attentional and emotional regulation [101,102].
Although the fundamental principles of ME and IE are universal and can be applied in any culture or context, the cultural context can affect how people perceive and practice ME and IE.This systematic review found that most studies focused on North America, especially the United States, which has been a major country in ME and IE research.However, these concepts have also been studied in other countries, including Turkey, Canada, United Kingdom, Japan, and others.In countries like Japan, researchers have proposed ME scales with expanded dimensions to encompass aspects such as health promotion and sustainability [65].Given the cultural and social differences, it is important for researchers to be aware of the necessary adaptations for different cultural contexts, in terms of both measurement scales and intervention protocols.
Based on the studies analyzed in this review, it was found that the scales most frequently used for measuring IE were the Intuitive Eating Scale [10] and its different versions, and those for measuring ME were the Mindful Eating Questionnaire [34] and its different versions.Studies on the psychometric properties of the IE scales have been more consistent and systematic for the IES [10,11], which is based on four constructs: Body-Food Congruence, Eating for Physical Reasons and not Emotional Reasons, Reliance on Hunger and Satiety Cues, and Unconditional Permission to Eat.On the other hand, the scales for ME have important differences in their conceptual bases and psychometric properties.One factor that has likely contributed to this is the lack of a clear definition of ME.
Mantzios [9] points out that the lack of a clear definition of ME has resulted in variations in its description in the academic and clinical literature, as well as different psychometric tools, which interfere with comparisons of evidence between studies and the quality of evidence produced from clinical interventions.In addition to the discussions regarding semantics, there is a central problem in the definition of mindful eating: the attention to and perception of hunger and satiety during the meal results in a conflicting feedback loop for the ability to maintain a posture without judgment, as it ends up interfering, for example, when making decisions about eating [9].MEQ [34] and MES [36] are the scales most frequently used in studies, and although both are useful for measuring attention specifically focused on eating behavior, they have important issues to be discussed, especially regarding how they were developed and the constructs they comprise.The MEQ measures five constructs: disinhibition, awareness, external influences, emotional response, and distraction [34], while the MES measures six constructs: acceptance, awareness, non-reactivity, acting with awareness, routine, and non-structured eating [36].
Although the MEQ [36] was the first instrument proposed to measure ME, it was conceived based on items and constructs from various existing scales for assessing eating behavior and mindfulness, and there is the possibility of overlap between the constructs due to the selected items used to compose the scale.On the other hand, the MES [36] was proposed in a manner more consistent with the standard definitions of mindfulness, and its validity was assessed based on outcomes to which mindfulness-based interventions apply.However, it has the limitation of being conceived in a study involving a small (n = 127) and predominantly female (77.2%) sample of students.
Therefore, researchers must be aware of the limitations when choosing a scale to measure and interpret the results of research on ME and IE and, whenever possible, culturally adapt and test the reliability and validity of these scales before applying them to the target population.Low Cronbach's alpha values condition the reliability of the data.Therefore, researchers should prefer scales with high Cronbach values and ideally measure the alpha value each time the test is administered.Despite the limitations pointed out in this review, the currently available scales have allowed the measurement of ME and IE and the exploration of these concepts in different aspects of physical and mental health in the university population.
Another aspect identified in this review was the diversity of outcomes studied regarding ME and IE.The most frequently investigated outcomes were eating behavior and eating disorders; anthropometric measures, especially BMI; mental health; and body image.Studies including biochemical markers were scarce, possibly due to them being more expensive and complex to conduct.
Regarding the effects of ME and IE approaches in the university population, the evidence is limited due to the scarcity of clinical trials.It is still uncertain whether students can benefit from the effects of these approaches based on results from other studies conducted with the general population [103].In terms of psychological aspects, IE has been inversely associated with multiple indices of pathological eating, body image disturbances, and psychopathology and positively associated with positive psychological constructs such as positive body image, self-esteem, and well-being [15,104].According to a meta-analysis of clinical trials, mindfulness-based interventions have resulted in improvements in mindfulness scores and binge eating symptoms [105,106].Additionally, a meta-analysis of clinical trials found a significant weight loss effect of ME/IE strategies compared to no-intervention controls.However, these effects were not different from those observed for conventional diet programs [6].Regarding the influence of ME and IE on energy intake or diet quality, a systematic review conducted by Grider et al. [4] pointed out that the evidence is still too limited to draw strong conclusions, and the authors suggest high-quality study designs for future research.
IE and ME are not centered on body weight and weight loss, and in the scientific literature, it is not fully understood whether and how these approaches may affect weight development.Some studies have suggested that IE is inversely associated with maladaptive eating behaviors, such as restrained, emotional, and external eating [107], and that ME and IE could be a practical approach to weight control; however, the effects that are observed when ME and IE are compared to non-intervention controls are no longer observed when ME and IE interventions are compared to conventional diet programs [6].
So far, we are not aware of any studies that have compared the effects of ME and IE on health, and it is not possible to say whether there is any type of advantage of one approach over the other.Both include the process of being mindful about eating without judgment, connecting with bodily sensations and sensory experiences with food, noticing hunger and satiety, and making conscious food choices.However, Kerin et al. [108] studied the associations between the IES and MES subscales, and they showed that some associations were small or nonsignificant, suggesting that some ME and IE components have more in common than others.For example, acceptance (a subscale of the MES) showed the greatest and most consistent overlap with all three subscales of IE and with Unconditional Permission to Eat, while Eating for Physical Reasons and not Emotional Reasons showed overlap with present eating, acceptance, and acting with awareness.It is necessary to better investigate the interfaces and differences between ME and IE and to identify the extent to which these approaches produce similar or distinct effects on eating behavior and health.
Future cohort and RCT studies with university students are needed to measure the effectiveness of ME and IE interventions in promoting healthy eating and preventing and/or treating obesity and chronic diseases in this population.Considering that ME and IE can influence attention regulation, emotion regulation, and executive function [109,110], future studies could contribute to better clarify the effects of these approaches on the mental health and academic performance of higher education students.
This review contributes to clarifying the state of the art regarding ME and IE in the university population and provides important insights into the measurement scales and existing gaps in the research with higher education students in order to support researchers.A limitation of this review is that despite extensive research in various databases, there is always a possibility that some studies may have been missed.

Conclusions
Although ME and IE have received increased attention in recent years, there are still significant gaps in the scientific knowledge on the subject.It can be considered that the scientific evidence on ME and IE in higher education students is still limited, especially due to most studies being cross-sectional in nature, conducted with small sample sizes, and lacking appropriate control groups in clinical trials and longitudinal study data.Most studies are cross-sectional, of short duration, and with a predominance of female individuals, of normal weight, residing in the USA and Europe.IES-2 and MEQ were the instruments most frequently used, and the measurement of ME and IE occurred predominantly in studies related to eating behavior and psychological features.Clearly, it is important that further research better assess the effects of ME and IE on diet quality, overweight/obesity management, and cardiometabolic markers, especially cohort studies and RCT.

Figure 1 .
Figure 1.PRISMA flow diagram illustrating the identification of studies.

Figure 1 .
Figure 1.PRISMA flow diagram illustrating the identification of studies.

Figure 2 .
Figure 2. Countries and years of publication of the studies included in this systematic review.

Figure 2 .
Figure 2. Countries and years of publication of the studies included in this systematic review.

Figure 3 .
Figure 3. Outcomes evaluated in the studies included in this systematic review.

Figure 3 .
Figure 3. Outcomes evaluated in the studies included in this systematic review.

Table 1 .
PICO criteria for inclusion of studies.
OutcomeScales used to measure ME and IE and associated outcomes.

Table 2 .
Study participant characteristics for included studies measuring mindful eating and intuitive eating in higher education students.

Table 3 .
Scales and questionnaires used to measure mindful eating and intuitive eating.