Increased fruit consumption was favorably associated with dietary habits, obesity, sedentary time, and physical fitness among Greek children and adolescents

Introduction

During the school age, it is crucial to establish healthy dietary habits, as they tend to persist into adulthood (1). This highlights the importance of promoting higher fruit intake at a young age (1). Consuming fruits has been linked to a reduced risk of obesity, improved psychological well-being, and enhanced gut health (2). Increased fruit consumption relates to a decreased risk of hypertension, stroke, heart disease, and cancer (3). In contrast, unhealthy eating patterns, such as a lack of fruits and vegetables, can contribute to developing conditions like diabetes, obesity, cardiovascular diseases, and weakened immunity, even during childhood (4).

While each country has dietary recommendations regarding fruit and vegetable consumption, these guidelines share many similarities. The World Health Organization (WHO) recommends that children and adolescents consume at least five daily servings of vegetables and fruits, amounting to a minimum of 400 g per day (5). At the same time, European and USA dietary guidelines emphasize the inclusion of fruits in children’s diets, as they provide essential nutrients like vitamins, calcium, and dietary fiber (5,6).

Children’s eating habits, such as fruit consumption, depend largely on their socio-demographic characteristics and are linked to other lifestyle factors [e.g., obesity, sedentary lifestyle, physical activity (PA), etc.] (7-17). Analytically, scientific data has shown a correlation between fruit consumption and the age of children (7). In addition, it has been determined that watching television and using computers are contributing causes because they frequently encourage the consumption of fast food while ignoring fruits (8). For instance, among overweight Canadian children, longer sedentary time was associated with lower fruit consumption (9). A review of multiple studies also found moderate evidence linking sedentary time, particularly television viewing, to reduced fruit intake in children and adolescents (10). Scientific evidence suggests that higher fruit consumption among schoolchildren aged 6 to 18 years is associated with increased PA levels and potentially better physical fitness (PF) (11-13). Additionally, it is thought that the absence of fruit and vegetable markets discourages children from making healthy food choices, which adds to childhood obesity (14). Previous findings concluded that lower frequency of fruit intake is correlated to children’s overweight status, while higher fruit consumption is associated with lower body mass index (BMI) and reduced risk of childhood obesity (9,15-17). Lastly, it appears that children’s sleep quality is correlated with unhealthy eating behaviors (18-20).

Although fruit consumption has been linked to sedentary time, childhood obesity, PA, and PF in children and adolescents, most studies have examined these relationships separately and in small age ranges (8-20). Additionally, no scientific evidence has correlated fruit consumption with healthy eating habits. Also, there is a lack of national and representative studies that have evaluated the prevalence of fruit intake among schoolchildren and the factors associated with it. Therefore, the study intends to significantly add to the body of current scientific literature by presenting descriptive data regarding the relationship between increased fruit consumption and its favorable consequences and correlates in children of school age. This knowledge can inform health policies aimed at improving fruit consumption.

The present study seeks to specifically report on the prevalence of increased fruit intake among schoolchildren and explore potential relationships between increased fruit consumption and sedentary time, obesity, dietary habits, PA, and PF while accounting for several confounders. We present this article in accordance with the STROBE reporting checklist (available at https://jphe.amegroups.com/article/view/10.21037/jphe-24-1/rc).

Methods

Participants

A large, nationally representative sample of Greek students 8 to 17 years old was used for the study. Specifically, it utilized population-based data from a nationwide school-based survey known as the EYZHN (National Action for Children’s Health) program, which was carried out under the direction of the Greek Ministry of Education and the Harokopio University of Athens to document health and lifestyle-related variables for all Greek students. A formal letter was sent by the Greek Ministry of Education to all the country’s Primary and Secondary Education Boards, inviting all of Greece’s primary and secondary schools to take part in the EYZHN initiative. The experimental protocols of the study were explained to all children, and each child who participated verbally gave their consent. Anthropometric, nutritional, sedentary time, PA, PF, gender, and age data were gathered between March and May 2015. In addition, parents provided formal agreement for their children to participate in the school health survey after being informed about it in writing. The working sample’s chi-square P value, when compared to the current sample that included the age-sex distribution of all Greek areas, was 0.93, indicating that it was representative of all Greek students.

Assessment of demographic data

Principals from the various schools gave demographic data about the students, such as date of birth, gender, and school. Based on their dates of birth and examination, the individuals’ precise ages were determined.

Assessment of anthropometric data

To achieve maximum validity and precision, children’s height, waist circumference, and body weight were measured in the morning at schools using a standardized technique conducted by qualified physical education (PE) specialists. The devices, such as weight scales, were also systematically calibrated. Using a consistent technique, students’ height and body weight were assessed in the morning without shoes. Children were told to dress modestly and to stand with their feet close together and their arms at their sides to ensure that their body weight was distributed equally. With an accuracy of 100 g, weight was measured using electronic scales while the subject was standing straight up. The children’s weight was evenly divided across their feet, with their head, back, and buttocks on the vertical axis, and their stature was measured to the nearest 0.1 cm. Using a flexible measure to the closest 0.1 cm, the waist circumference was measured at the midpoint between the top of the iliac crest and the lower edge of the least perceptible rib. Every measurement was done twice, and the average was determined if the results were within one centimeter of each other. The children were classified as normal weight, overweight, or obese based on their BMI using the age- and gender-specific cut-off criteria established by the International Obesity Task Force (21). One definition of central obesity was waist circumference to height ratio (WHtR) ≥0.5 (22).

Assessment of fruit consumption

The main outcome of this study was increased fruit consumption, which was determined by whether participants consumed two or more fruits or juices every day. Increased fruit intake is a question in the KIDMED (Mediterranean Diet Quality Index in children and adolescents) index (23). Students who did not consume fruit or juice daily were classified as “non-consumers”. The question “Has a second fruit or juice every day?” was used to measure fruit consumption, and responses were incorporated for analysis.

Assessment of dietary habits

With the help of their instructors and/or information technology professors, the participating children filled out an electronic questionnaire at school that captured their eating habits. The participants’ eating habits were evaluated using the KIDMED index (23). This index has 16 yes/no questions that evaluate adherence to basic dietary guidelines for children and adolescents as well as the principles of the Mediterranean diet. Positive responses are given a value of +1, whereas negative ones receive a value of −1. The KIDMED total score starts at 0 and goes up to 12, with ≥8 signifying excellent adherence to the Mediterranean diet (sufficient dietary habits); 4–7, which indicates average adherence to the Mediterranean diet and a need for improvement to fulfill dietary requirements (relatively sufficient dietary habits); and ≤3, which indicates poor adherence to the Mediterranean diet and generally low diet quality (insufficient dietary habits).

Assessment of 24-hour movement behaviors

Using a validated questionnaire with closed-type items on the frequency, duration, and level of children’s participation in school-related PA, organized sports, and leisure time PA, the assessment of self-reported PA and sedentary time was conducted (24). To calculate the average daily time the participants spent engaging in moderate-to-vigorous physical activity (MVPA), the reported physical activities were multiplied by the minutes of MVPA and divided by 7. Children who participated in MVPA for at least 60 minutes a day satisfied the PA requirements (sufficient PA). The weekly frequency and length of each session of engaging in sedentary activities were multiplied, and the resulting sedentary time was divided by 7. Students were categorized as sedentary or not based on the threshold of 2 hours per day (increasing vs. acceptable) when it came to screen viewing, which was employed as a proxy for sedentary time (25). Children and adolescents were categorized as fulfilling the criteria for adequate sleep if they slept for at least 9 and 8 hours per day, respectively. Sleep duration was measured by self-report (26). Participants were categorized as having inadequate sleep if they slept fewer hours each day than the recommended amount (26).

Assessment of PF levels

The children’s PF levels were evaluated using the Euro-fit PF test battery (27). Five tests comprised the test battery: a maximal 10×5 m shuttle run test (10×5 m SRT) to evaluate speed and agility; a multi-step 20 m shuttle run test (20 m SRT) to evaluate aerobic capacity; a sit-ups in 30 s (SUs) test to evaluate hip flexor and abdominal endurance; a standing long jump (SLJ) test to evaluate lower body explosive strength; and a sit-and-reach (SR) test to evaluate flexibility (27). Every fitness test was administered in class by physical education specialists who were trained to administer them using a comprehensive manual. A consistent measurement approach was used to reduce inter-rater variability between schools. Only the 20 m SRT data was used in this investigation.

Ethical approval

The study was conducted following the Declaration of Helsinki (as revised in 2013). The ethics of this research was approved by the Ethical Review Board of the Ministry of Education and the Ethical Review Committee of Harokopio University (No. 37/20-02-2013) and individual consent for this analysis was obtained from children’s parents.

Statistical analyses

The frequency (percentages) or mean ± standard deviation was used to represent descriptive statistics. The Student’s t-test was utilized to evaluate variations in the means of normally distributed data, and the chi-square test was employed to investigate correlations between categorical variables. A binary logistic regression analysis was carried out to ascertain the possible impact of various dietary practices on increased fruit consumption (yes vs. no). The odds ratio (OR) was computed with the appropriate 95% confidence interval (CI) and corrected for confounding variables. A hierarchical binary logistic regression analysis was also carried out to evaluate the possible influence of different lifestyle and demographic characteristics on the frequency of fruit consumption. To get an adjusted association of the covariates while adjusting for confounding variables, the OR with the appropriate 95% CI was computed. The model’s goodness-of-fit was evaluated using Hosmer and Lemeshow’s goodness-of-fit test, and residual analysis was carried out to find outliers and significant data using the Dbeta, leverage, and Cook’s distance D statistics. Lastly, discriminant analysis was used to assess each component’s strength concerning the result. SPSS Inc., Chicago, IL, USA, provided the SPSS version 23.0 software for Windows, which was used for all statistical studies. Two-sided hypotheses were considered statistically significant if the P value was less than 0.05.

Results

Approximately 40% of the total population, or 177,091 participants aged 8 to 17 years old from elementary (8 to 12 years old) and middle (13 to 17 years old) public and private schools, took part in the study (49% girls and 51% boys). The basic descriptive statistics of the whole sample, broken down by gender, are shown in Table 1. Boys and girls were 9.9±2.8 and 9.8±2.8 years old, on average. Compared to girls, boys reported eating fruits two or more times a day in a slightly larger percentage (51.2% vs. 48.8%, P=0.74). Boys and girls differed significantly in anthropometric measurements, dietary habits, PA levels, sedentary time, and aerobic fitness (all P values <0.001).

The anthropometric and behavioral characteristics of the research subjects are displayed in Table 2, based on their daily fruit consumption (≥2/day or none). When compared to non-consumers of the same gender, both genders who were classified as increased fruit consumers had better aerobic fitness measurements, improved anthropometric measurements, healthier eating habits, decreased sedentary time, and more sleep (all P values <0.01).

The unadjusted binary logistic regression analysis showed that regular consumption of fish, pulses, olive oil, and two yogurts and/or cheese (40 g) daily increased the odds of being a fruit consumer in both genders while skipping breakfast and frequently consuming fast food and sweets decreased those odds (Table 3, Model 1). The eating behaviors were still substantially correlated with fruit consumption in both genders even after controlling for age, BMI, and waist circumference (Table 3, Model 2). The results were not significantly affected by additional adjustments for sedentary time, sleep duration, or PA (Table 3, Model 3).

Stepwise logistic regression analyses (4 Models) were carried out to examine the potential associations of various factors on fruit consumption (increased vs. non) in both genders based on the prior results, which indicate that fruit consumers had a better lifestyle profile than non-consumers (Table 4). According to the preliminary data, the likelihood of being a fruit consumer fell by 8% for boys and 12% for girls for every year of age growth. Furthermore, the likelihood of being a fruit consumer was lowered by central obesity and overweight/obesity (Table 4, Model 1). Additional KIDMED index adjustment (Table 4, Model 2) did not change the findings of the impact of age and obese status. On the other hand, healthy eating practices raised the likelihood of fruit consumption by almost seven times in both genders. Increased sedentary time and insufficient sleep hours reduced the likelihood of being a fruit eater by 22% and 25%, respectively, after additional adjustment for sedentary time and sleep (Model 3). Lastly, the significance of the preceding components persisted after the analysis (Model 4) considered the assessments of aerobic fitness and PA levels. Additionally, it was discovered that low levels of PA were linked to a lower likelihood of eating fruit, whereas higher levels of aerobic performance were linked to a higher likelihood of doing so for both genders.

To evaluate if the predictors could more accurately separate increased fruit consumers from non-fruit consumers, discriminant analysis was used. Standardized function coefficients indicate that age (−0.29), dietary practices (0.81), and PA (0.45) are more important in differentiating between individuals who regularly eat fruits and those who do not, for both genders. According to the categorization results, 84% of increased fruit consumers and 56% of non-consumers were properly predicted by the model.

Discussion

Key findings

The most noteworthy findings are as follows: (I) nearly half of schoolchildren consumed two or more fruits daily; (II) boys and girls who consumed fruit had a healthier lifestyle; and (III) increased fruit consumption was significantly and independently correlated with genders reduced sedentary time and increased sleep duration, aerobic fitness, and healthy eating habits.

Strengths and limitations

The current study included multiple factors and was conducted throughout a wide age range (8 to 17 years old). Since primary and secondary education are required in Greece, a sizable portion of the student body was examined in the study. The approach taken makes it possible to compare our findings with those of other representative and comparable research. To the best of our knowledge, only a small number of studies have examined various anthropometric and lifestyle correlates of fruit consumption in a community-representative sample.

The study is limited by methodological problems and the lack of assessment of potential confounding variables, such as socioeconomic position and fruit availability, which were likely linked to fruit consumption. Since this study is cross-sectional, causality cannot be determined. Furthermore, the data on PA, sleep, sedentary time, and eating behaviors were self-reported, making them vulnerable to bias in favor of reporting. However, there was no motivation for participants to give misleading information because their responses were anonymous. Finally, statistical significance may be reached even with such a large sample size.

Comparison with similar research and explanations of findings

We found that almost 50% of the participants consume two or more fruits daily. Fruit consumption varies considerably among and within countries (28). Findings from the National Health and Nutrition Examination Survey (2015–2018) in the USA stated that nearly 75% of children and adolescents (2–19 years old) consumed fruit, daily (29), while the average daily consumption of total fruit is almost to the lowest level of the recommended intake range (1 cup), for both genders (6). In contrast, a review study of 58 papers, aiming to investigate fruit and vegetable intake in adolescents living in North America, Europe, and Oceania (using the KIDMED questionnaire) concluded that the average fruit consumption was strongly below the recommendations of 400 g per day in almost all the examined populations (30). Moreover, a study among nine European countries revealed that fruit intake in 11-year-old children was in all countries far from reaching dietary guidelines on national and international levels (31), while, another study examining food habits in 162,305 adolescents (11 to 15 years old) in 35 countries referred to large differences in food habits between countries with the frequency of fruit consumption varied from on average 2.8 to 5 d/week (32). Probably, the fact that in Greece there is a high availability of fruit throughout the year largely explains the increased consumption by children and adolescents compared to other countries.

Regarding age effect in increased fruit consumption, our data showed that there was a significant reduction from 54% at age 8 years old to 31% at age 18 years old. These findings follow a study from the United Kingdom including 2,131 individuals aged 2–23 years old which stated that fruit intake started to reduce from the age of 7 years old for both genders and reached its lowest level during adolescence (17 years old) (33). Also, a study conducted by the Center for Disease Control and Prevention (CDC) reported that the proportion of children and adolescents who consumed any fruit daily reduced with age, while approximately 80% of children (aged 6–11 years old) consumed any fruit, compared with 64.0% of adolescents (aged 12–19 years old) (29). These results are probably attributed to the fact that older children had more autonomy in fruit intake than younger ones who were more likely to be under their parent’s influence.

In the present sample of schoolchildren, increased fruit consumption was significantly associated with lower odds for overweight/obesity and central obesity by almost 20% and 10%, respectively, in both genders, after adjustment for several covariates. Several studies that have explored the association between childhood obesity and fruit intake revealed that adequate fruit consumption was associated with a lower risk of obesity, while, in contrast, a low frequency of fruit intake was associated with overweight (9,15-17). The WHO contends that promoting healthy food choices, such as fruit and vegetable intake could delay or prevent childhood obesity (34).

In the current study, we found that students who had increased fruit consumption were nearly seven times more likely to have sufficient dietary habits, while it was a fact that increased fruit consumption was negatively associated with unhealthy eating habits such as frequent consumption of fast food and sweets. Several national dietary guidelines and WHO recommend that children should consume adequate amounts of fruits as part of a healthy diet, as they provide a lot of essential nutrients and may help protect against a wide range of diseases (5,6,34,35).

According to our findings, sleeping and sedentary time were strongly correlated with higher fruit consumption. Both genders’ probabilities of eating fruit were 22% lower for people who reported spending more than 2 hours a day in front of a screen. A review by Costigan et al. included evidence of a negative correlation between sedentary time and healthy eating habits, and another review by Pearson and Biddle suggested there was a moderate correlation between sedentary time and children’s and teens’ consumption of fruits and vegetables (36,37). Additionally, moderate support for the same correlations in children and adolescents was found in a review of cross-sectional studies (10).

Furthermore, the available data suggests that inadequate sleep duration (<8–9 h/d) is linked to a 25% decrease in the likelihood of eating fruit for both genders. A study among 33- to 60-month-old children concluded that more frequent fruit and vegetable consumption was associated with shorter nap time (18). Also, the results of research on 213,879 young adolescents showed that fruit and vegetable intake once a week or more was connected to fewer sleep difficulties (19). In a recent review among schoolchildren, the results revealed that high consumption of fruits and vegetables was associated with better sleep quality (20). Finally, in another review, the authors reported significant associations between short sleep duration and lower-quality diets (38).

Regarding the potential association of fruit consumption with PA and PF it seems that insufficient PA levels decreased the odds of being a fruit consumer by almost 30%, while it appeared that better aerobic performance was associated with a greater probability of being a fruit consumer, in both genders. Research among girls showed that those whose parents reported high PA modeling had higher odds of consuming ≥5 portions of fruits and vegetables, daily (13). The present findings are in line with a study among 9,842 schoolchildren aged 6- to 17-year-old which proposed that high levels of PA were associated with higher consumption of juice, fruits, and vegetables among both boys and girls (11). Comparably, earlier research on children and adolescents showed that eating a second fruit each day was linked to a higher chance of meeting PA recommendations for both sexes (12).

The current results suggested a trend that as aerobic fitness performances were improved, the odds of eating fruit increased, even though the likelihood ratio of aerobic fitness performance to predict fruit consumers was small (for every one lap increase in the 20 m SRT, there is an increase per 1% of being a fruit consumer, 95% CI: 1.01–1.02, P value <0.001). These results are consistent with earlier research on schoolchildren, which showed a favorable correlation between PF and eating habits and higher probabilities of a healthy aerobic fitness level when eating fruits daily (39,40). Additional investigation is necessary to validate this correlation. Improved aerobic fitness involved leading a healthy lifestyle, and these kids were most likely more inclined to favor healthy dietary habits such as fruit intake.

Implications and actions needed

Given the available data, it is extremely concerning that public health programs should address persistent issues with fresh, high-quality fruit access and price in addition to knowledge gaps in nutrition (41,42). To prevent negative health impacts in the future, it is important to establish healthy fruit consumption habits in children and create circumstances that encourage fruit consumption at home, at school, and in the community.

Conclusions

The current study proposed that increased fruit intake is significantly associated with a healthier lifestyle profile (e.g., PA, PF, obesity, sedentary time, sleeping time) among Greek schoolchildren. Public health efforts should be targeted on access and affordability of fresh fruits and to help schoolchildren adopt healthier dietary habits.

Acknowledgments

The authors want to thank the study participants for their willingness to take part.

Funding: None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jphe.amegroups.com/article/view/10.21037/jphe-24-1/rc

Data Sharing Statement: Available at https://jphe.amegroups.com/article/view/10.21037/jphe-24-1/dss

Peer Review File: Available at https://jphe.amegroups.com/article/view/10.21037/jphe-24-1/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jphe.amegroups.com/article/view/10.21037/jphe-24-1/coif). All authors reported this study was supported by the Hellenic Ministry of Education and Religious Affairs, and the Department of Nutrition and Dietetics Graduate Program, Harokopio University of Athens. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted following the Declaration of Helsinki (as revised in 2013). The ethics of this research was approved by the Ethical Review Board of the Ministry of Education and the Ethical Review Committee of Harokopio University (No. 37/20-02-2013) and individual consent for this analysis was obtained from children’s parents.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Craigie AM, Lake AA, Kelly SA, et al. Tracking of obesity-related behaviours from childhood to adulthood: A systematic review. Maturitas 2011;70:266-84. [Crossref] [PubMed]
2. Saxe-Custack A, LaChance J, Hanna-Attisha M. Child Consumption of Whole Fruit and Fruit Juice Following Six Months of Exposure to a Pediatric Fruit and Vegetable Prescription Program. Nutrients 2019;12:25. [Crossref] [PubMed]
3. Boeing H, Bechthold A, Bub A, et al. Critical review: vegetables and fruit in the prevention of chronic diseases. Eur J Nutr 2012;51:637-63. [Crossref] [PubMed]
4. Schröder H. Protective mechanisms of the Mediterranean diet in obesity and type 2 diabetes. J Nutr Biochem 2007;18:149-60. [Crossref] [PubMed]
5. World Health Organisation European Region. Food-based dietary guidelines in the WHO European Region. Copenhagen: WHO, Europe, 2003.
6. U.S. Department of Health and Human Services, U.S. Department of Agriculture. 2020. 2020-2025 Dietary Guidelines for Americans, 9th ed. Assessed November 10, 2023. Available online: https://www.dietaryguidelines.gov/sites/default/files/2021-3/Dietary_Guidelines_for_Americans-2020-2025.pdf
7. Health Survey for England. Children Aged 5 to 15 Who Eat Five or more Portions of Fruit and Vegetables per Day, by Age. 2016. Accessed September 5, 2023. Available online: http://healthsurvey.hscic.gov.uk/data-visualisation/data-visualisation/explore-the-trends/fruit-vegetables.aspx
8. Nicklas TA, Johnson CC, Farris R, et al. Development of a school-based nutrition intervention for high school students: Gimme 5. Am J Health Promot 1997;11:315-22. [Crossref] [PubMed]
9. Hadi H, Nurwanti E, Gittelsohn J, et al. Improved Understanding of Interactions between Risk Factors for Child Obesity May Lead to Better Designed Prevention Policies and Programs in Indonesia. Nutrients 2020;12:175. [Crossref] [PubMed]
10. Stiglic N, Viner RM. Effects of screentime on the health and well-being of children and adolescents: a systematic review of reviews. BMJ Open 2019;9:e023191. [Crossref] [PubMed]
11. Manz K, Mensink GBM, Finger JD, et al. Associations between Physical Activity and Food Intake among Children and Adolescents: Results of KiGGS Wave 2. Nutrients 2019;11:1060. [Crossref] [PubMed]
12. Tambalis KD, Panagiotakos DB, Psarra G, et al. Concomitant Associations between Lifestyle Characteristics and Physical Activity Status in Children and Adolescents. J Res Health Sci 2019;19:e00439. [PubMed]
13. Pearson N, Timperio A, Salmon J, et al. Family influences on children's physical activity and fruit and vegetable consumption. Int J Behav Nutr Phys Act 2009;6:34. [Crossref] [PubMed]
14. Yang S, Zhang X, Feng P, et al. Access to fruit and vegetable markets and childhood obesity: A systematic review. Obes Rev 2021;22:e12980. [Crossref] [PubMed]
15. Yang N, Kim K. Is the Perceived Fruit Accessibility Related to Fruit Intakes and Prevalence of Overweight in Disadvantaged Youth: A Cross-Sectional Study. Nutrients 2020;12:3324. [Crossref] [PubMed]
16. Jakobsen DD, Brader L, Bruun JM. Association between Food, Beverages and Overweight/Obesity in Children and Adolescents-A Systematic Review and Meta-Analysis of Observational Studies. Nutrients 2023;15:764. [Crossref] [PubMed]
17. Yu HJ, Li F, Hu YF, et al. Associations of physical activity and fruit and vegetable intake with well-being and depressive symptoms among obese schoolchildren in Wuhan, China: a cross-sectional study. BMC Public Health 2018;18:986. [Crossref] [PubMed]
18. Holmes JF, St Laurent CW, Spencer RMC. Unhealthy Diet Is Associated With Poor Sleep in Preschool-Aged Children. J Genet Psychol 2021;182:289-303. [Crossref] [PubMed]
19. Zhao Y, Qu D, Liang K, et al. Eating habits matter for sleep difficulties in children and adolescents: A cross-sectional study. Front Pediatr 2023;11:1108031. [Crossref] [PubMed]
20. Amat-Camposo R, Riquelme-Gallego B, Soto-Méndez MJ, et al. Relationship between diet, nutritional aspects and sleep quality in a pediatric population. Nutricion hospitalaria 2023; [Crossref] [PubMed]
21. Cole TJ, Bellizzi MC, Flegal KM, et al. Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ 2000;320:1240-3. [Crossref] [PubMed]
22. Browning LM, Hsieh SD, Ashwell M. A systematic review of waist-to-height ratio as a screening tool for the prediction of cardiovascular disease and diabetes: 0·5 could be a suitable global boundary value. Nutr Res Rev 2010;23:247-69. [Crossref] [PubMed]
23. Serra-Majem L, Ribas L, Ngo J, et al. Food, youth and the Mediterranean diet in Spain. Development of KIDMED, Mediterranean Diet Quality Index in children and adolescents. Public Health Nutr 2004;7:931-5. [Crossref] [PubMed]
24. Grigorakis DA, Georgoulis M, Psarra G, et al. Prevalence and lifestyle determinants of central obesity in children. Eur J Nutr 2016;55:1923-31. [Crossref] [PubMed]
25. Colley RC, Wong SL, Garriguet D, et al. Physical activity, sedentary behaviour and sleep in Canadian children: parent-report versus direct measures and relative associations with health risk. Health Rep 2012;23:45-52. [PubMed]
26. Paruthi S, Brooks LJ, D'Ambrosio C, et al. Consensus Statement of the American Academy of Sleep Medicine on the Recommended Amount of Sleep for Healthy Children: Methodology and Discussion. J Clin Sleep Med 2016;12:1549-61. [Crossref] [PubMed]
27. Eurofit: Handbook for the Eurofit Tests of Physical Fitness. 1993:1-75.
28. György B, Barna M, Kopeć A, et al. Review of current practices to increase the intake of fruit and vegetables. European Union. 2015. Available online: https://health.ec.europa.eu/system/files/2016-11/2015_myhealthyfamily_literaturereview_en_0.pdf
29. Wambogo EA, Ansai N, Ahulwalia N, et al. Fruit and Vegetable Consumption Among Children and Adolescents in the United States, 2015-2018. NCHS Data Brief 2020;1-8. [PubMed]
30. Rosi A, Paolella G, Biasini B, et al. Dietary habits of adolescents living in North America, Europe or Oceania: A review on fruit, vegetable and legume consumption, sodium intake, and adherence to the Mediterranean Diet. Nutr Metab Cardiovasc Dis 2019;29:544-60. [Crossref] [PubMed]
31. Yngve A, Wolf A, Poortvliet E, et al. Fruit and vegetable intake in a sample of 11-year-old children in 9 European countries: The Pro Children Cross-sectional Survey. Ann Nutr Metab 2005;49:236-45. [Crossref] [PubMed]
32. Vereecken CA, De Henauw S, Maes L. Adolescents' food habits: results of the Health Behaviour in School-aged Children survey. Br J Nutr 2005;94:423-31. [Crossref] [PubMed]
33. Albani V, Butler LT, Traill WB, et al. Fruit and vegetable intake: change with age across childhood and adolescence. Br J Nutr 2017;117:759-65. [Crossref] [PubMed]
34. Wallace TC, Bailey RL, Blumberg JB, et al. Fruits, vegetables, and health: A comprehensive narrative, umbrella review of the science and recommendations for enhanced public policy to improve intake. Crit Rev Food Sci Nutr 2020;60:2174-211. [Crossref] [PubMed]
35. World Health Organization. Increasing fruit and vegetable consumption to reduce the risk of noncommunicable diseases. 2023. Assessed November 28, 2023. Available online: https://www.who.int/tools/elena/interventions/fruit-vegetables-ncds
36. Costigan SA, Barnett L, Plotnikoff RC, et al. The health indicators associated with screen-based sedentary behavior among adolescent girls: a systematic review. J Adolesc Health 2013;52:382-92. [Crossref] [PubMed]
37. Pearson N, Biddle SJ. Sedentary behavior and dietary intake in children, adolescents, and adults. A systematic review. Am J Prev Med 2011;41:178-88. [Crossref] [PubMed]
38. Dashti HS, Scheer FA, Jacques PF, et al. Short sleep duration and dietary intake: epidemiologic evidence, mechanisms, and health implications. Adv Nutr 2015;6:648-59. [Crossref] [PubMed]
39. Tambalis KD, Panagiotakos DB, Psarra G, et al. Association of cardiorespiratory fitness levels with dietary habits and lifestyle factors in schoolchildren. Appl Physiol Nutr Metab 2019;44:539-45. [Crossref] [PubMed]
40. Thivel D, Aucouturier J, Isacco L, et al. Are eating habits associated with physical fitness in primary school children? Eat Behav 2013;14:83-6. [Crossref] [PubMed]
41. Deroover K, Bucher T, Vandelanotte C, et al. Practical Nutrition Knowledge Mediates the Relationship Between Sociodemographic Characteristics and Diet Quality in Adults: A Cross-Sectional Analysis. Am J Health Promot 2020;34:59-62. [Crossref] [PubMed]
42. McKinnon L, Giskes K, Turrell G. The contribution of three components of nutrition knowledge to socio-economic differences in food purchasing choices. Public Health Nutr 2014;17:1814-24. [Crossref] [PubMed]