Introduction

Grazing is a problematic eating behavior characterized in the literature by the repetitive and unplanned ingestion of small/modest amounts of food throughout a period of time in the absence of hunger/satiety cues [1,2,3]. It has been subtyped into non-compulsive grazing, characterized by eating in a distracted or mindless manner, and compulsive grazing, described as the sense of inability to resist or going back to repetitively eat tempting foods while trying to resist [1].

Grazing and/or grazing-type behaviors, such as picking or nibbling and snaking [1], have been increasingly studied in the adult population, particularly in patients undergoing bariatric surgery. Evidence shows associations with higher Body Mass Index (BMI) and obesity, poor weight loss or weight regain, and increased psychopathology [4,5,6]. For example, grazing has been associated with greater negative affect, emotional dysregulation, emotional eating, food addiction, dietary disinhibition, anxiety/depression, and less sensitivity to gain weight [6,7,8,9,10,11]. Moreover, recent research showed that grazing can be conceptualized as an eating behavior in association with low to moderate degrees of loss of control eating [3].

Grazing, or grazing-type behaviors, seems to be notably present in community/college samples, ranging from 48.2 to 91% [11, 12], in adults with obesity, ranging from 23.3 to 47.1% [4, 12], and among adult eating disorders samples—from 57.6 to 58.3% in patients with bulimia, from 34.3 to 41.6% in patients with anorexia nervosa, and from 44 to 67.8% in patients with binge eating disorder [12, 13]. Grazing-type behaviors seem to be also prevalent in children and adolescents with eating disorders: 34.4% in anorexia nervosa or atypical anorexia nervosa, and 52.2% in bulimia nervosa or subclinical bulimia nervosa [14]. However, no previous research assessed grazing and its correlates in a non-clinic population of children.

Healthy eating in childhood plays an important role to promote an appropriate cognitive and physical development, and it also reduces the risk of overweight or obesity [15]. The presence of problematic eating behaviors is greater in overweight/obese children than in their normal-weight peers and has been linked to problematic eating and obesity in adulthood [16, 17]. Given the associations previously described between grazing, weight loss outcomes, and problematic eating psychopathology in adults, the need to investigating if these associations hold true in childhood is a timely matter in the field.

Despite the lack of research on grazing in children, a few studies investigated snacking behavior in this population. Rhee et al. [18] reported that 89.2% of overweight children and 59.5% of normal-weight children engage in excessive snacking behaviors, defined as eating between meals and at night. Additionally, other studies point out that the amount of food particularly consumed from snacks is thought to be associated with the children’s unhealthy eating habits such as skipping meals and overweight [19, 20].

Children who experience loss of control eating present a higher snack consumption [21], and are also thought to present higher body image dissatisfaction, more anxiety/depressive symptoms, and higher BMI [22]. Finally, evidence suggests that children who engage in loss of control eating episodes also present poor emotional regulation strategies [23, 24] and that greater consumption of snacks may occur when children are alone with no social interaction, especially in case of children with overweight [25].

Parents are key players in the development and maintenance of their children eating behavior (including snacking behavior) by playing a major role in choosing when the eating will occur, the context, the quality of the food and the portion sizes available, which feeding practices will be adopted, and also by influencing their children’s eating habits via their own beliefs and eating choices [26,27,28,29,30,31]. Considering the role of parental feeding practices in their children's feeding behavior, the literature showed contradictory results. Some research suggests that restrictive feeding practices and greater psychological control have been associated with higher BMI and greater excessive snacking among both normal-weight and overweight children, meaning that coercive practices seem to have a paradoxically effect on children overeating [27, 30, 32,33,34,35]. Additionally, parental concerns about their children’s weight have been associated with parental restrictive feeding practices [34]. However, it is important to note that, in overweight/obese children (aged 8–12 years.), firm behavioral control seems to be associated with less snacking [18]. More pressure to eat and less covert control (parental food control practices that are unnoticed by the child) have been associated with increased ingestion of unhealthy snacks [33,34,35,36]. Parental feeding practices, such as pressure to eat and greater restriction, are also associated with increased odds of loss of control eating among 7–13 years old children with overweight and obesity [37].

Together, these data highlight the possible interplay between grazing behavior and anxiety/depression, body dissatisfaction, social withdrawn, and parental feeding practices. Therefore, the aim of this work is to investigate the associations between parents’ report of their children's grazing behavior, children’s psychological variables (anxiety/depression, withdrawn, and body dissatisfaction), children eating habits, and parental feeding practices among primary school children and their parents. According to the literature presented, we hypothesized that children’s psychological variables, eating habits, and parental feeding practices would be associated with grazing behavior in children. Specifically, we expected that greater psychological distress (depression, anxiety and withdrawn symptoms, and body image dissatisfaction) would be linked with more children grazing behavior. Moreover, considering that grazing behavior has been described as an unplanned eating pattern [1], we expect that this behavior would be favored in a context of poor eating habits and lack of eating routines. Additionally, parental concerns about their children’s weight are expected to be greater for children with higher BMI. Such concerns would be associated with parental restrictive feeding practices, which in turn, would be linked with children's grazing behavior.

Methods

Participants

Participants were children and their parents or legal guardian (henceforward identified as the parent) in four public primary schools in the North of Portugal. Schools were located in urban areas. Inclusion criteria were age between 6 and 10 years. Children presenting development disorders (e.g. autism spectrum disorder), learning and intellectual disabilities were excluded.

Procedures

This cross-sectional study was approved by the ethical committees of the university involved and by the Portuguese General Department of Education (DGE). Teachers from the different classes gave each student a sealed envelope with a set of questionnaires and the informed consent form to all children attending school that day. Parents whose children were interested in participating in the study would send the signed consent form for themselves and their children. Parents (and their children) accepting participating in this study responded to the questionnaires and sent the envelope back to the teacher. The researcher visited the school on a fixed day to collect the envelope with the completed questionnaires and informed consent form signed. During this visit, the weight and height of all participating children were measured.

Measures

Anthropometric data

A SECA model 899 flat scale (SECA Corp., Hamburg, Germany, 2008) was used to collect weight. Height was assessed with a portable stadiometer with no shoes (in centimeters). BMI z-scores for age and sex were calculated by the World Health Organization Anthroplus software 3.2.2. version [38]. The National Centre for Health and Statistics (NCHS) grow curves were used to define BMI percentiles for age and sex.

Psychological questionnaires.

Responded by parents about children

Sociodemographic questionnaire This questionnaire evaluated age, sex and school year.

Repetitive Eating Questionnaire (Rep(eat)-Q) [2] This questionnaire was originally developed to the adult population and was adapted, for the purpose of this study, to be responded by parents about their child’s grazing behavior (See Online Resource 1 for the adapted questionnaire and Online Resource 2 for preliminary psychometric properties). This is a 12-item questionnaire responded on a 7-point Likert scale (0 = never, 6 = every day) which result in a total score and two subscales: compulsive grazing and repetitive eating. Higher scores indicate a more pronounced grazing eating pattern. Cronbach´s α for this sample was 0.91 for the total score, 0.80 and 0.87 for the compulsive grazing and repetitive eating subscales, respectively.

Child behaviour checklist (CBCL) [39, 40] For the purpose of this study, only Social Withdrawn (eight items) and Anxiety/Depression (13 items) scales were used. Higher scores indicate more psychological distress. Cronbach’s s α for this sample was 0.63 for the withdrawn scale and 0.74 for anxiety/depression scale.

Family eating and activity habits questionnaire (FEAHQ) [41] This measure was translated and back-translated by the authors of this work for the purpose of this study. Only the 12-item eating habits and style subscale regarding the child’s behavior was used in this study. All items were assessed on a 5-point Likert scale from “never” to “always”. Higher scores indicate more inappropriate children eating habits (e.g., eat while watching television; eat straight from the pot; not having an eating schedule). Cronbach’s α is 0.61 for eating habits and style child subscale.

Responded by parents about themselves

Child feeding questionnaire (CFQ) [42, 43] For this study the following subscales were used: Parents’ concerns about child weight (three items that assess parents' concerns about the child’s risk of being overweight), Monitoring (three items that assess the degree to which parents oversee their child’s eating), Restriction (eight items that assess the degree to which parents restrict their child’s access to food), and Pressure to eat (four items that assess parents' predisposition to pressure their children to eat more food). Responders rate each item on a 3-point Likert scale from “never” to “always”. Higher scores indicate a higher endorsement on the respective parental feeding practice or weight concern. Cronbach’s α for this sample was.72 for Parents’ concerns about child weight subscale, 0.94 for Monitoring children’s eating subscale, 0.75 for Restriction subscale and 0.71 for Pressure to eat subscale.

Responded by children with help from their parents.

Collins’ Silhouettes scale [44, 45] This is a pictorial instrument to examine body image dissatisfaction. Seven male/female silhouettes ordered in morphology from 1 (thinness) to 7 (obesity) are showed and subjects are asked to select the silhouette which they believed is most similar to their own (Self) as well as the silhouette, which they most desire (ideal self). The discrepancy between the “self” and the “ideal self” represents the degree of body image dissatisfaction.

Statistical analysis

Data analyses were conducted with IBM® SPSS® Statistics 22.0. A Mann–Whitney test was conducted to investigate sex differences in the Rep(eat)-Q scores and to investigate differences between participants with missing excluded and participants not excluded in the model tested with a path analysis (further information in ‘Results’ section). Spearman correlations investigated associations between parents’ report of children’s grazing behavior, and the other children’s and parents’ variables. Finally, IBM® SPSS® Amos™ 24.0 was used to conduct a path analysis to test a model investigating how some children’s variables (such as BMI z-score, anxiety/depression symptoms and body image dissatisfaction), children eating habits, and parental feeding practices (such as parents concerns about child weight and parental food restriction) were associated to children’s grazing behavior. The overall model fit was examined using the following goodness-of-fit indices: nonsignificant chi-square (CMIN), Comparative Fit Index (CFI), Tucker-Lewis Index (TLI), Incremental Fit Index (IFI), Normed Fit Index (NFI) > 0.90, Root Mean Square Error of Approximation (RMSEA) < 0.08, and Standardized Root Mean Square Residual (SRMR) < 0.08 indicated an acceptable model fit [46].

Results

Initially, 530 children (all students attending school that day) and their parents were invited to participate. Two hundred did not return the questionnaires before the researcher’s visit to the school. A total of 330 dyads were recruited. The mean age of the children was 7.55 (SD = 1.19) years, 50.9% (n = 168) were girls and 49.1% (n = 162) boys. Mean BMI 17.63 (SD = 2.69), BMI z-score was 0.87 (SD = 1.24), and mean BMI percentile 71.19 (SD = 27.71): 1.5% (n = 5) were underweight; 54.5% (n = 180) were of normal weight; 18.5% (n = 61) had overweight; 25.5% (n = 84) had obesity.

Table 1 presents the mean and standard deviation of all the psychological measures used.

Table 1 Means and standard deviations for measures used in the study
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The Rep(eat)-Q scores ranged within the non-clinical values. There were no differences between boys and girls in the Rep(eat)-Q total score (Boys: M = 0.69, SD = 0.83; Girls: M = 0.60, SD = 0.99; U = 10,880, p = 0.148), compulsive grazing (Boys: M = 0.47, SD = 0.84; Girls: M = 0.42, SD = 0.89; U = 11,687, p = 0.456), and repetitive eating subscales (Boys: M = 0.88, SD = 1.05; Girls: M = 0.78, SD = 1.18; U = 10,835, p = 0.108).

Table 2 presents spearman correlations among variables under study. Our data suggest that higher scores in the parents’ report of children’s grazing behavior were associated with older age, higher BMI z-score, greater children’s anxiety/depression and withdrawn symptoms (CBCL scales), increased parents’ concerns about child weight and parental feeding restriction (CFQ subscales), and more disorganized children's eating habits and style (such as eating when bored/angry; eating while watching TV, eating disorderly throughout the afternoon, eating in the bedroom; FEAHQ subscale). Parents’ report of children’s repetitive and total grazing behavior were also significantly correlated with increased body image dissatisfaction (Collins’ Silhouettes).

Table 2 Non-parametric correlations between Rep(eat)-Q scales, socio-demographic/clinical information, and psychological variables in a non-clinical sample of children
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Additionally, Table 2 also shows that there were significant correlations between the other variables assessed. Specifically, older age was associated with greater body image dissatisfaction, increased parents’ concerns about child weight and less pressure to eat (CFQ subscale). Higher BMI z-score was associated with greater body image dissatisfaction, increased parents’ concerns about child weight, monitoring (CFQ subscale), parental feeding restriction and less pressure to eat. Greater children’s anxiety/depression symptoms were associated with this behavior children’s withdrawn symptoms, more pressure to eat, greater parental feeding restriction and more disorganized children’s eating habits and style. Greater children’s withdrawn symptoms were associated with more pressure to eat. Greater body image dissatisfaction was associated with increased parents’ concerns about child weight, monitoring, parental feeding restriction and less pressure to eat. Increase parent’s concerns about child weight were associated with greater parental feeding monitoring, parental feeding restriction, more disorganized children's eating habits, and style and less pressure to eat. Finally, more parental feeding monitoring was associated with greater parental feeding restriction.

The main aim of this study was to investigate how parental and children’s variables interact and are associated with grazing behavior in children. The model tested was based on the variables shown to be significantly associated with the parent report of their children’s grazing behavior in previous correlation analyses, and on the evidence from the scarce literature published. To run the path analyses of the proposed model, we decided to exclude the participants who presented missing values. Ninety-two participants (27.9% of the initial sample) were excluded from the initial sample, resulting in a final sample composed of 238 children. A Mann–Whitney test for independent samples showed that participants excluded did not differ significantly from the final sample concerning age (selected: M = 7.55, DP = 1.19; not selected: M = 7.53, SD = 1.20; U = 10,825, p = 0.870), sex (selected: 53.4% girls; not selected: 44.6% girls; U = 9985, p = 0.152), BMI z-score (selected: M = 0.84, SD = 1.23; not selected: M = 0.95, SD = 1.28; U = 10,552, p = 0.610), parental concerns about child weight (selected: 3.18; not selected: 2.98; U = 8172, p = 0.347), parental feeding restriction (selected: 3.63; not selected: 3.40; U = 6777, p = 0.125), body image dissatisfaction (selected: 0.07; not selected: 0.17; U = 6946, p = 0.334), children eating habits and style (selected: 9.62; not selected: 10.41; U = 4711, p = 0.290), anxiety/depression (selected: 6.08; not selected: 6.46; U = 7853, p = 0.850), and total grazing (selected: 0.63; not selected: 0.68; U = 8548, p = 0.976).

Figure 1 depicts the final model tested, which presents an excellent fit to our data: CMIN = 12.679; DF = 11; p = 0.315; RMSEA = 0.025, 90% confidence interval (CI) = 0.000, 0.075; CFI = 0.990; NFI = 0.935; TLI = 0.982; IFI = 0.991; SRMR = 0.045. The model showed that a higher BMI z-score in children was associated with increased parental concerns about their child’s weight. Greater parental concerns about the child’s weight were associated with more restrictive feeding practices, which, in turn, were linked to higher scores of the parent report of children’s grazing behavior. On the other hand, higher BMI z-scores and greater parental concerns about child weight were linked with greater body image dissatisfaction of children, which was also linked to increased scores of children’s grazing behavior. Finally, inappropriate children eating habits and style were directly and indirectly associated with more grazing behavior via higher anxiety/depression.

Fig. 1
figure 1

Path analysis: model tested for the interplay between children’s and parental variables to understand grazing in children. Rep(eat)-Q repetitive eating questionnaire, BMI z-score body mass index z-score for age, CBCL child behaviour checklist, CFQ child feeding questionnaire, FEAHQ family eating and activity habits questionnaire; correlations significant when *p < 0.05; **p < 0.01; ***p < 0.001

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Discussion

Grazing has been associated with higher BMI, obesity, poor weight loss outcomes in obesity treatments, and increased psychopathology in adults with obesity and in community samples [1, 2, 4,5,6,7,8,9, 12, 47]. However, little is known about grazing in children. The aim of this work was to investigate the link between the parents’ report of their children's grazing behavior, children’s psychological variables, children’s eating habits, and parental feeding practices.

Regarding children’s variables, we found an association between children's grazing behavior, and children’s anxiety/depression and withdrawn symptoms, body image dissatisfaction, BMI z-score, and age. Since grazing has been conceptualized as an eating behavior in association with loss of control eating [3]. Previous research pointed to an association between children’s experience of loss of control eating with snack consumption, anxiety, depressive symptoms, body image dissatisfaction and BMI [21, 22]. Previous results from a study by Salvy et al. [48] also suggested a link between the consumption of snacks and lack of social interaction. Regarding the association found between BMI z-score and grazing, it is important to note that 44% of the children assessed were overweight or obese, which stands higher than the national prevalence rates estimates of 37.1% [49]. Considering the association between grazing and lower weight loss in adults with obesity, this is a finding with important clinical implications for weight loss programs in children. Additionally, we found that grazing is associated with older age in this sample, which is in line with the findings stressed by Kass et al. [14] in a sample of children and adolescents with eating disorders. This might seem contrary to findings in adult populations in which grazing is inversely correlated with age [2, 12]. These apparently contradictory findings may be explained by two reasons: (1) grazing behavior in the youth may increase with age, probably because older children have more access to food and more autonomy regarding food choice; (2) loss of control eating, which is associated with grazing, is typically present among adolescents and young adults [50]. Thus, studies entailing an adult sample with older adults may find the inverse association between grazing and age.

Additionally, our results establish an association between grazing behavior in children and parental concerns about the child’s weight, parental restriction of their child’s eating and more inappropriate children eating behaviors. These findings are in line with previous research showing that more parents’ concerns about their child's weight are associated with greater parental restriction [51]. Moreover, other authors suggested that greater restriction, psychological control, and more inappropriate eating habits are associated with excessive snacking and loss of control eating among children [18, 27, 30, 32,33,34, 37]. Despite previous literature showing that pressure to eat is associated with increased odds of loss of control eating and increased unhealthy food intake [33, 37], in this study no association was found between this form of parental feeding practice (pressure to eat) and grazing behavior. Further research should clarify the underlying mechanisms that explain the association between pressure to eat and eating behavior. However, it is possible that parents who engage more in pressure to eat practices may not be particularly sensitive to identify grazing behavior in their children.

Finally, our data support an interplay between parental feeding practices, children’s psychological state, and grazing. Grazing seems to be higher when parents engage in restrictive feeding practices and when children have a more inappropriate eating habits and style (e.g., eat while watching television; eat straight from the pot; not having an eating schedule). However, our data do not allow us to conclude about the direction of this relationship, and it is not possible to know if parents engage in restrictive practices because of their children’s grazing behavior, or whether grazing behavior is a result of parental feeding practices. Previous research shows that the extent to which patients restrict their children’s eating may be related to their concerns about children’s overweight [52] and that less restriction is used when parents believe their children can self-regulate their eating [53]. However, overt restriction may lead to consequent consumption of food when made freely available [26] which is particularly facilitated in a context of more inappropriate children eating habits and style. Since restriction can compromise self-regulation, parents should be advised on how to promote eating self-regulatory skills in their children [53]. Moreover, parents should stimulate healthy eating habits by rewarding children for trying new foods, promoting repeated exposure, establish rules for what can be eaten and drunk, stimulate meals eaten together and modeling eating behavior [31].

BMI z-score seems to be linked with greater parents’ concerns about their child’s weight, and body image dissatisfaction. Greater parents’ concerns about their child’s weight, in turn, were associated with more restrictive parental feeding practices, which is in line with previous research [34]. Considering the importance of parental feeding practice to the children’s eating behavior, future research should investigate how parental BMI and eating behavior could impact their attitude towards their children. Additionally, children with greater body image dissatisfaction and anxiety/depression symptomatology also tend to present more grazing. Although we show an association between grazing, psychological distress, and parental practices, future studies should explore its role as a predictor of poor weight loss in children undergoing weight loss interventions as seen in adult samples [1]. Moreover, prevalence rates of grazing in childhood are still unknown and future research should provide a better representation of this problematic eating behavior in this population. Finally, despite literature regarding interventions to target grazing behavior is minimal Mantzios et al. [54] suggested that mindfulness, compassion, and acceptance interventions are useful in decreasing grazing.

This study presents some limitations, namely the cross-sectional design of the study limits the discussion in terms of the association between the variables under study and does not allow us to establish causality. Additionally, almost 40% of the parents did not return the questionnaires and we could not obtain any information from these families. This may indicate sample biases and limits the generalization of the results. Moreover, some of the main child’s variables (e.g., grazing, psychological distress) of this study were evaluated using parental reports. Considering that some of the items refer to internal experiences that may not be easily assessed observationally (e.g. felt upset after snacking), future research should investigate the validity of these items used as parent-report and test, for example, an adapted version of the Rep(eat)-Q for older children to allow self-report assessment of grazing. Nonetheless, research has shown that parents are reliable in reporting their children’s external behaviors in general [55], and also eating behaviors [56]. Additionally, children also responded to the body image dissatisfaction measure with help from their parents which may bias their answers. Finally, we did not collect data on the presence of impulsive disorders such as ADHD. Future research should investigate how the presence of impulsive behaviors impacts grazing behaviors and the associated variables.

Conclusion

Grazing has been widely studied in adult patients undergoing bariatric surgery and in community samples, but, to the best of our knowledge, no previous study evaluates this important eating behavior in children. Our results showed that grazing is also present in childhood and is related to higher BMI z-score, anxiety/depression symptoms, social withdrawn, and higher body image dissatisfaction. We also show that grazing in children tends to occur in a context of more inappropriate children eating habits and restrictive parental feeding practices, stressing the interplay between the child's psychological state and parental feeding practices. This work provides additional evidence that children’s psychological distress, children's eating habits, and restrictive feeding practices are associated with problematic eating behaviors, including grazing. Therefore, these variables should be considered to improve healthy eating habits and in weight loss intervention for children.