Comparison of eating behaviors between single-child and child with siblings: an analytical cross-sectional study

Abstract

Introduction

The importance of accurately understanding school-aged children (7–12 years) and implementing efforts to safeguard and promote their physical and psychological health is widely recognized. Changes in family structure, including the rise of single-child households, may influence children’s eating behaviors; however, evidence from Iran is limited. The present study aimed to determine and compare eating behaviors among children (aged 7–12 years) from single-child and multi-child families.

Methods

To assess eating behaviors among elementary school children in Khalkhal City, 318 boys and girls from urban and rural primary schools were selected using cluster random sampling. Demographic questionnaire, Physical Activity Questionnaire for Older Children (PAQ-C), and Children’s Eating Behavior Inventory (CEBI) were applied. SPSS software (IBM SPSS Statistics, Armonk, USA) was used for data analysis.

Results

The mean age was 9.55 ± 1.77 years in the single-child group and 9.71 ± 1.70 years in the multi-child group, with no statistically significant difference between groups (P = 0.42). The mean global CEBI score was significantly higher in the multi-child group compared to the single-child group (113.91 ± 6.76 vs. 105.47 ± 8.31; P < 0.001). Similarly, the mean scores of skill (35.30 ± 3.33 vs. 32.29 ± 4.57), compliance (52.85 ± 3.85 vs. 49.45 ± 4.57), and preferences (25.75 ± 3.15 vs. 23.72 ± 3.62) were significantly higher in the multi-child group (all P < 0.001). Multivariable logistic regression analysis demonstrated that multi-child participants had significantly higher odds of being in the “normal or good” category compared to single children. For skill, the fully adjusted model showed an OR of 19.49 (95% CI: 2.25–168.80; P = 0.007). For compliance, the adjusted OR was 19.23 (95% CI: 5.43–68.05; P < 0.001). For preferences, the adjusted OR was 2.77 (95% CI: 1.64–4.69; P < 0.001).

Conclusions

We found that having siblings was associated with more scores across all measured domains, including skills, compliance, and preferences. These differences remained even after controlling for confounders.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1186/s12887-026-07145-2.

Introduction

Children constitute a substantial proportion of the world’s population; in developing countries, they account for nearly 50% of the total population. The importance of accurately understanding this population group and implementing efforts to safeguard and promote their physical and psychological health is widely recognized [1, 2].

In many countries, declining fertility and changes in family structure have reduced household size and increased the proportion of single-child families [3, 4]. In Iran, the marked decline in fertility has increased the number of smaller families and single-child households, which may have implications for children’s development and health-related behaviors [5, 6]. Single children may have fewer opportunities for sibling-based interaction at home, which can influence social development, behavioral regulation, and exposure to diverse eating patterns [7–9]. It has been suggested that being a single child may be associated with childhood obesity and unhealthy eating behaviors. Studies show that children with siblings engage in more daily physical activity than single children [10, 11]. In a national study in China, children from single-child families had lower levels of physical activity and consumed more fast food and sugar-sweetened beverages [11]. In contrast, having more children may promote more balanced parenting practices and may reduce the likelihood of chronic nutrition-related problems [12].

Eating behavior is defined as the thoughts, actions, and tendencies through which an individual consumes solid and liquid foods [13]. Unhealthy or inappropriate eating behaviors during childhood and adolescence are major concerns because they may be associated with chronic diseases in adulthood [14]. In general, eating habits and food preferences are acquired early in childhood and reflect behavioral characteristics that may evolve over time based on personal experiences [15]. Evidence indicates that eating behaviors interact with body composition and body mass index (BMI). In recent years, childhood and adolescent obesity has become a major public health challenge in developed countries and is expanding globally [16–18]. Healthy eating behaviors support appropriate growth in weight, height, and head circumference and help prevent malnutrition, growth retardation, acute feeding problems, and long-term health conditions such as cardiovascular diseases, type 2 diabetes, cancer, obesity, osteoporosis, and impaired bone development due to insufficient calcium intake [19, 20]. Adequate nutrition plays a critical role in children’s neurological, cognitive, emotional, and social development [21].

Despite growing global evidence on the role of family structure in shaping children’s eating behaviors [22, 23], there is limited data from Iran. Moreover, the 7–12 age range represents a critical developmental period during which eating behaviors become more stable and are influenced by family environment and social impacts [24, 25]. Therefore, the present study aimed to determine and compare eating behaviors among children (aged 7–12 years) from single-child and multi-child families. We hypothesized that children with siblings would demonstrate more favorable eating behaviors compared to single children.

Materials and methods

Study design and participants

To assess eating behaviors among elementary school children in Khalkhal City, Ardabil province 318 boys and girls from urban and rural primary schools were selected between September and December 2025 using cluster random sampling. Primary schools were first selected as clusters. A total 15 primary schools from urban and rural areas were included in the study. Classes were then randomly selected from the selected schools, and eligible students were randomly recruited. The inclusion criteria were children aged 7–12 years enrolled in urban or rural primary schools, parental age > 17 years, parents’ ability to read and write in Persian; absence of severe or chronic maternal illness that could substantially interfere with childcare and feeding practices, absence of major Axis I psychiatric disorders in the child according to DSM criteria, term birth, appropriate birth weight, absence of major congenital anomalies affecting feeding, chewing, swallowing, or nutritional status such as craniofacial disorders, and no use of medications affecting appetite, eating behavior, or growth.

Not meeting the required age criteria for the mother or child, incomplete questionnaires, child living in a single-parent household, lack of parental motivation to participate were exclusion criteria of the present study. Incomplete questionnaires were defined as those with more than 10% missing data.

The sample size was calculated using the standard formula considering 95% power and an α of 5%. The required sample size was estimated based on the study by Patro et al. [26], who examined behavioral patterns in children aged 5–15 years. Regarding the 10% withdrawal rate a sample of 318 Iranian children aged 7–12 years old were selected.

The research protocol was in accordance with the guidelines of the Declaration of Helsinki. The Ethics Committee in Research of Khalkhal University of Medical Sciences approved the study protocol (Ethical code: IR.KHALUMS.REC.1403.007, Approval date: 2024-10-15). Informed consent was obtained from all the parents at the beginning of the study. The reporting of this cross-sectional study follows the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement. (STROBE-checklist supplementary file)

Data collection

Weight was measured using a digital scale with minimal clothing and without additional items. Height was measured in the standing position without shoes, with heels against the wall, head upright, and eyes facing forward, using a measuring tape. Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared (kg/m²) [27]. Data on physical activity and eating behaviors were collected using the relevant questionnaires through face-to-face interviews with parents.

Data were collected using the following questionnaires:

1) Demographic questionnaire: Included information such as sex, age, residence status, number of family members, ethnicity, parental education levels, and parental jobs.

2) Physical Activity Questionnaire for Older Children (PAQ-C): The PAQ-C was developed by Crocker et al. (1997) [28]. It is a 7-day self-report physical activity recall questionnaire consisting of 10 items. Responses are rated on a 5-point Likert scale (1 = no activity to 5 = five to seven times or more), where higher scores indicate higher physical activity. The total PAQ-C score is calculated as the mean of the first nine items [29]. In the study by Zameni et al. (2020), content validity index was 0.91 and reliability was examined using internal consistency and test–retest methods; Cronbach’s alpha was 0.89 in the overall sample, and the intraclass correlation coefficient (ICC) over a 15-day interval in 120 students was 0.92 [30].

3) Children’s Eating Behavior Inventory (CEBI): In this study, eating behavior outcomes were defined based on the CEBI framework. Food preferences refer to the child’s acceptance and variety of food choices; eating-related motor skills reflect the child’s ability to independently manage eating tasks such as using utensils; and behavioral compliance indicates the child’s cooperation with mealtime structure and parental guidance. The CEBI is a parent-report measure designed to assess eating behaviors and feeding-related problems during mealtimes in children aged 2–12 years [31]. The scale includes 40 items: 28 child-focused items (assessing food preferences, eating-related motor skills, and behavioral compliance) and 12 items focused on parents and the family system (assessing the extent of parental control over the child’s eating behavior, parents’ cognitions and emotions regarding feeding, and family interactions). The validity and reliability of the CEBI have also been confirmed in Iran [32]. The CEBI child-focused items (28 items) are scored on a 5-point scale (1–5). Therefore, the total score across the 28 child items ranges from 28 to 140, with a median of 70. While the subscales scores provide detailed information regarding specific eating dimensions, the total score is also computed and interpreted to provide an overall index of eating behaviors. Subscales (child-focused items) are: Child Food Preferences (items 3, 5, 15, 18, 19, 23, 28), Child Motor Skills (items 1, 4, 6, 11, 12, 16, 20, 24), and Child Behavioral Compliance (items 2, 7, 8, 9, 10, 13, 14, 17, 21, 2 2, 25, 26, 27).

Statistical analysis

In this study, the normal distribution of the data was evaluated using the Kolmogorov-Smirnov statistical test. All quantitative data were described as mean ± standard deviation, and categorical data as numbers (percentages). An independent t-test was used to compare quantitative variables in two groups (single-child and multi-child), and a Chi-square test was used to compare categorical variables. The correlation between global CEBI score, Motor Skills, Behavioral Compliance, Food Preferences was evaluated using the Pearson test. The relationship between single-child status (independent variable) and quantitative Motor Skills, Behavioral Compliance, Food Preferences scores (dependent variables) was assessed using linear regression analysis in 3 models: Model 1: without adjustment, Model 2: linear regression analysis with adjustment for age and sex, Model 3: linear regression analysis with adjustment for age, sex, residence status, disease, father’s job, mother’s job, father’s education, mother’s education, number of family members, ethnicity, and mean PAQ-C. Odds ratios (95% CI) for the qualitative status of Motor Skills, Behavioral Compliance, Food Preferences scores (normal or good) according to the status of single child (yes or no) using Multivariable logistic regression in 3 models: model 1: unadjusted, model 2: adjusted for age and sex, model 3: adjustment for age, sex, residence status, disease, father’s job, mother’s job, father’s education, mother’s education, number of family members, ethnicity, and mean PAQ-C. The adjustment variables were selected based on previous studies and their potential role as confounders in the relationship between single-child status and children’s eating behaviors [33–35]. SPSS software (IBM SPSS Statistics, Armonk, USA) was used for data analysis. A p-value less than 0.05 was considered a significant level.

Results

Demographic characteristics and comparison of behavioral scores between single-children and children with siblings

A total of 318 children, including 159 children from single-child and 159 children from multi-child families, were enrolled in the study. The mean age was 9.55 ± 1.77 years in the single-child group and 9.71 ± 1.70 years in the multi-child group, with no statistically significant difference between groups (P = 0.42). There were no significant differences between the two groups regarding sex, place of residence, disease status, parental job, or parental education level (P for all > 0.05). The mean PAQ score was similar in both groups (P = 0.93). The mean global CEBI score was significantly higher in the multi-child group compared to the single-child group (113.91 ± 6.76 vs. 105.47 ± 8.31; P < 0.001). Similarly, the mean scores of skill (35.30 ± 3.33 vs. 32.29 ± 4.57), compliance (52.85 ± 3.85 vs. 49.45 ± 4.57), and preferences (25.75 ± 3.15 vs. 23.72 ± 3.62) were significantly higher in the multi-child group (P for all < 0.001). In the qualitative classification, a significantly higher proportion of multi-child participants were categorized as “good” in skill and compliance dimensions compared to single children (P = 0.002 and P < 0.001, respectively). Likewise, the proportion of participants classified as “good” in preferences was higher in the multi-child group (59.1% vs. 40.3%; P < 0.001). CEBI scores were categorized into three groups based on tertiles of the score distribution. The lowest tertile was classified as weak, the middle tertile as normal, and the highest tertile as good. Classification based on BMI-for-age Z-scores indicated that the majority of participants in both single-child and multi-child groups had normal nutritional status. The proportions of overweight, obesity, and thinness were low, and no cases of severe thinness were identified. Moreover, there was no significant difference between the groups in BMI-for-age Z-score distribution (P = 0.57). (Table 1)

Table 1.

The characteristics of the subjects in the single-child and multi-child groups

Variables	Single-child (n = 159)	Multi-child (n = 159)	P- value
Age (years)	9.55 ± 1.77	9.71 ± 1.70	0.42*
Sex (N) (%)			0.19**
Male	48 (30.2)	59 (37.1)
Female	111 (69.8)	100 (62.9)
Residence status (N) (%)			0.30**
Urban	153 (96.2)	149 (93.7)
Rural	6 (3.8)	10 (6.3)
Disease (N) (%)			0.09**
Yes	5 (3.1)	1 (0.6)
No	154 (96.9)	158 (99.4)
Father’s job (N) (%)			0.77**
Government	42 (26.4)	49 (30.8)
Private	31 (19.5)	23 (14.5)
Freelance	42 (26.4)	41 (25.8)
Worker	39 (24.5)	41 (25.8)
Unemployed	5 (3.1)	5 (3.1)
Mother’s job (N) (%)
Government	29 (18.23)	22 (13.83)	0.45**
Private	10 (6.3)	7 (4.4)
Student	1 (0.6)	0 (0)
Housekeeper	119 (74.8)	130 (81.8)
Father’s education (N) (%)
Elementary	14 (8.8)	16 (10.1)	0.72**
Middle and high school	78 (49.1)	71 (44.7)
University	67 (42.1)	72 (45.3)
Mother’s education (N) (%)
Elementary	8 (5.0)	10 (6.3)	0.58**
Middle and high school	84 (52.8)	75 (47.2)
University	67 (42.1)	74 (46.5)
Mean PAQ-C ()	2.91 ± 0.62	2.91 ± 0.61	0.93*
CEBI scores
Global	105.47 ± 8.31	113.91 ± 6.76	< 0.001*
Motor Skills	32.29 ± 4.57	35.30 ± 3.33	< 0.001*
Behavioral Compliance	49.45 ± 4.57	52.85 ± 3.85	< 0.001*
Food Preferences	23.72 ± 3.62	25.75 ± 3.15	< 0.001*
Motor Skills.cat (N) (%)
Weak	0 (0)	0 (0)	0.002**
Normal	12 (7.5)	1 (0.6)
Good	147 (92.5)	158 (99.4)
Behavioral Compliance.cat (N) (%)
Weak	0 (0)	0 (0)	< 0.001**
Normal	31 (19.5)	3 (1.9)
Good	128 (80.5)	156 (98.1)
Food Preferences.cat (N) (%)
Weak	0 (0)	0 (0)	< 0.001
Normal	95 (59.7)	65 (40.9)
Good	64 (40.3)	94 (59.1)
Anthropometric indices
Weight (kg)	33.35 ± 10.47	33.95 ± 9.33	0.59
Height (cm)	136.96 ± 12.52	137.22 ± 12.45	0.85
BMI (kg/m2)	17.50 ± 3.90	17.84 ± 3.44	0.40
Z score (BMI for age), (N) (%)#
Severe thinness	0 (0)	0 (0)	0.57**
Thinness	2 (1.3)	0 (0)
Normal	131 (82.4)	138 (86.8)
Overweight	19 (11.9)	16 (10.1)
Obese	5 (3.1)	4 (2.5)
Severe obese	2 (1.3)	1 (0.6)

Values are expressed as mean ± SD. *P was estimated using Independent t-test for comparison between the two groups. ** P was estimated using Chi-square test

PAQ-C: Physical Activity Questionnaire for Older Children, CEBI: Children’s Eating Behavior Inventory

#Z score (BMI for age): ≤ -3 (severe thinness), -3 to -2 (thinness), -2 to + 1 (normal), + 1 to + 2 (overweight), + 2 to + 3 (obese), and ≥ + 3 (severe obese)

Comparison of eating behavior scores between boys and girls

Among the participants, 107 were boys and 211 were girls. There were no statistically significant differences between boys and girls in the global CEBI score (109.23 ± 8.85 vs. 109.93 ± 8.58; P = 0.49). Similarly, no significant differences were observed in skill (P = 0.78), compliance (P = 0.49), or preferences scores (P = 0.26). (supplementary Table 1)

Correlations between global CEBI Score and its dimensions

Pearson correlation analysis demonstrated significant positive correlations between the global CEBI score and skill (r = 0.70, P < 0.001), compliance (r = 0.77, P < 0.001), and preferences (r = 0.59, P < 0.001). Skill was positively correlated with compliance (r = 0.31, P < 0.001) and preferences (r = 0.23, P < 0.001). Additionally, compliance showed a positive correlation with preferences (r = 0.11, P = 0.03). All correlations were statistically significant. (supplementary Table 2)

The relationship between single-child status (independent variable) and quantitative motor skills, behavioral compliance, food preferences scores (dependent variables)

Linear regression analysis indicated that single-child status was significantly associated with lower motor skills, behavioral compliance, food preferences scores across all models. For skill, the unadjusted model showed a significant association (B = 3.00, R² = 0.12, P < 0.001), which remained significant after adjustment for age and sex (Model 2: B = 3.05, R² = 0.13, P < 0.001) and after full adjustment for demographic and familial variables (Model 3: B = 3.54, R² = 0.18, P < 0.001). Similar patterns were observed for compliance (Model 3: B = 3.91, R² = 0.17, P < 0.001) and preferences (Model 3: B = 2.45, R² = 0.16, P < 0.001), indicating robust associations after controlling for potential confounders. (Table 2)

Table 2.

The relationship between single-child status (independent variable) and quantitative Motor Skills, Behavioral Compliance, Food Preferences scores (dependent variables)

Variables	B (Unstandardized)	R square	P-value
Motor Skills
Model 1a	3.00	0.12	< 0.001
Model 2b	3.05	0.13	< 0.001
Model 3c	3.54	0.18	< 0.001
Behavioral Compliance
Model 1a	3.39	0.14	< 0.001
Model 2b	3.47	0.14	< 0.001
Model 3c	3.91	0.17	< 0.001
Food Preferences
Model 1a	2.03	0.08	< 0.001
Model 2b	2.07	0.08	< 0.001
Model 3c	2.45	0.16	< 0.001

P < 0.05 was considered as significant

(a) Model 1: linear regression analysis without adjustment, (b) Model 2: linear regression analysis with adjustment for age and sex, (c) Model 3: linear regression analysis with adjustment for age, sex, residence status, disease, father’s job, mother’s job, father’s education, mother’s education, number of family members, ethnicity, and mean PAQ-C

Odds ratios (95% CI) for the qualitative status of motor skills, behavioral compliance, food preferences scores (normal or good) according to the status of single child (yes or no)

Multivariable logistic regression analysis demonstrated that multi-child participants had significantly higher odds of being in the “normal or good” category compared to single children. For skill, the fully adjusted model showed an OR of 19.49 (95% CI: 2.25–168.80; P = 0.007). For compliance, the adjusted OR was 19.23 (95% CI: 5.43–68.05; P < 0.001). For preferences, the adjusted OR was 2.77 (95% CI: 1.64–4.69; P < 0.001). (Table 3)

Table 3.

Odds ratios (95% CI) for the qualitative status of Motor Skills, Behavioral Compliance, Food Preferences scores (normal or good) according to the status of single child (yes or no)

Variables	B	OR (CI)	P- value
Motor Skills
Model 1a	2.55	12.89 (1.65-100.42)	0.01
Model 2b	2.56	12.94 (1.65-101.11)	0.01
Model 3c	2.97	19.49 (2.25–168.80)	0.007
Behavioral Compliance
Model 1a	2.53	12.59 (3.67–42.14)	< 0.001
Model 2b	2.63	13.87 (4.11–46.83)	< 0.001
Model 3c	2.95	19.23 (5.43–68.05)	< 0.001
Food Preferences
Model 1a	0.76	2.14 (1.37–3.35)	< 0.001
Model 2b	0.79	2.21 (1.41–3.48)	< 0.001
Model 3c	1.02	2.77 (1.64–4.69)	< 0.001

P < 0.05 statistically significant by Multivariable logistic regression

(a) model 1: unadjusted. (b) model 2: adjusted for age and sex. (c) model 3: adjustment for age, sex, residence status, disease, father’s job, mother’s job, father’s education, mother’s education, number of family members, ethnicity, and mean PAQ-C

Discussion

This study compared eating behaviors and nutrition-related challenges among 318 school-aged children—half of whom were single-child and half who had at least one sibling. We found that children growing up with siblings displayed significantly more scores across all measured domains, including skills, compliance, and preferences. These associations remained even after controlling for confounders. Interestingly, despite these behavioral differences, the two groups did not differ in BMI for age Z-scores or in levels of physical activity. Higher scores in the CEBI child-focused domains indicate healthier eating-related behaviors. In the food preferences domain, higher scores indicate greater acceptance and variety of foods. In the eating-related motor skills domain, higher scores reflect better independence in eating-related tasks. In the behavioral compliance domain, higher scores indicate greater cooperation with mealtime routines and parental guidance [31].

An explanation for the observed differences in CEBI scores may relate to parental perception and reporting behavior. Since the CEBI is a parent-reported instrument, parents of single children may exhibit greater attention or concern toward their child’s eating behaviors, which could affect their responses. This may partially explain the lower scores among single children, independent of actual differences in dietary intake. This interpretation is supported by the lack of significant differences in anthropometric indices, suggesting that behavioral differences may not necessarily translate into measurable nutritional disparities. Eating behaviors were also similar between boys and girls, suggesting that family structure may play a more prominent role than gender at this stage of development.

Our results are in line with earlier research emphasizing the role of family structure and sibling dynamics in shaping children’s eating behaviors [23, 36, 37]. Studies have shown that children with siblings are often exposed to a wider variety of foods, engage in more social interactions during meals, and receive more consistent modeling of healthy behaviors [38, 39]. These experiences appear to promote openness to trying new foods and to strengthen internal regulation of hunger and satiety. In contrast, single-children may have fewer opportunities for such peer-like modeling at home, and their meals may rely more heavily on one-to-one interactions with parents, which sometimes involve more pressure or control [40, 41]. Several mechanisms such as social modeling and observational learning, structured routines and family rules, practice of self-regulation, and reduced parental pressure may explain why having siblings appears to have healthier eating behaviors. However, these mechanisms were not directly measured in the present study and should be interpreted as potential explanations rather than confirmed causal pathways. Children often imitate the behaviors of those around them. When siblings share meals, they serve as natural role models, demonstrating food acceptance, portion control, and table manners [38, 42]. Repeated exposure through sibling modeling can help reduce food neophobia and encourage greater dietary variety [43]. Families with more than one child typically establish clearer mealtime routines (set times, consistent seating, and fewer distractions) to manage the group efficiently [44]. Once these rules are in place, they benefit all children equally, fostering greater consistency and compliance [45, 46]. Eating with siblings often requires patience, sharing, and waiting one’s turn that help children develop self-control around food and strengthen their skills related to self-regulation [47, 48]. Parents of single children sometimes feel heightened responsibility for their child’s intake and may become more controlling during meals, pressuring the child to eat or restricting certain foods. Research shows that these practices can related to poorer self-regulation and more problematic eating behaviors [49, 50]. However, the large odds ratios and wide confidence intervals observed in some models suggest potential instability and should be interpreted with caution.

Our finding that BMI for age Z-scores did not differ between the groups is also consistent with prior evidence showing that behavioral differences often emerge well before measurable changes in body composition become apparent [51, 52]. Middle childhood is a period of relatively stable growth, making BMI less sensitive to behavioral variations over short periods [53]. Anthropometric outcomes are shaped by many interacting factors (energy intake, expenditure, genetics, and the external food environment such as school cafeterias and neighborhood food options), so the influence of better eating behaviors may require time or supportive environments to translate into visible physical outcomes [54]. The absence of gender differences suggests that during middle childhood, family rules and shared routines tend to overshadow sex-specific dietary preferences. Previous longitudinal studies have found that gender gaps in diet quality and body image appear more clearly in early adolescence, when autonomy and peer influence increase [55–57].

A key strength of this study is the balanced sample (equal numbers of single and multi-child families) along with comprehensive adjustment for confounders such as socioeconomic status and parental factors. Including both rural and urban populations enhances the external validity and generalizability of the findings, while controlling for residence status helps reduce potential confounding. However, several limitations should be noted. The cross-sectional design prevents causal inference. The parent-related subscale of the CEBI was not separately analyzed in the present study. Both eating behaviors and physical activity were assessed using parent-reported questionnaires, which may introduce recall bias, social desirability bias, and common method bias. The sample was predominantly urban, so results may not generalize to rural areas with different food environments. Residual confounding may exist due to unmeasured variables such as household income, food environment, and parental dietary behaviors. Finally, while the behavioral scales showed good internal consistency, further validation across cultural contexts would strengthen confidence in these tools. Longitudinal studies are needed to confirm whether the behavioral advantages observed in children with siblings translate into better diet quality and healthier weight trajectories over time. Future work should also explore how parental feeding styles, sibling age spacing, and birth order interact to shape eating behaviors. Incorporating objective dietary assessments and biomarkers could clarify whether the observed behavioral differences correspond to nutritional adequacy. Finally, interventions that mimic sibling-like modeling, through peer or classroom programs, should be tested for their potential to improve eating behaviors among single children.

Conclusion

The findings indicate that children with siblings had significantly higher scores in food preferences, eating-related motor skills, and behavioral compliance compared to only children. These associations remained statistically significant after adjusting for demographic and socioeconomic variables. However, no significant differences were observed between the groups in anthropometric indices, including BMI forage z-scores, or in physical activity levels.

Authors’ contributions

HB: data curation, validation, collection supervision, review, and editing; TM: collection supervision, data entry; AB, and AB: analysis, and interpretation; JA and AN: data curation, validation; VA and HRM: collection supervision, manuscript writing, revision, and submission approval. All authors reviewed the manuscript. The final version of the manuscript was approved by all authors.

Funding

This work has been financially supported by the Khalkhal University of Medical Sciences.

Data availability

All data and materials are fully presented in the manuscript.

Declarations

Ethics approval and consent to participate

The research protocol was in accordance with the guidelines of the Declaration of Helsinki. The Ethics Committee in Research of Khalkhal University of Medical Sciences approved the study protocol (Ethical code: Ethical code: IR.KHALUMS.REC.1403.007). The informed written consent form was completed for all subjects at the beginning of the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.