Evaluation of nutrition knowledge level and eating attitude in adolescent athletes: cross-sectional study

MURAT URHAN1, EZGI KARATAŞ1, RANA NAGIHAN AKDER1, CEREN AKANALÇI1, MESUT NALÇAKAN2

1Ege University Faculty of Health Sciences Department of Nutrition and Dietetic, Izmir, Turkey; 2İzmir Metropolitan Municipality Eşrefpaşa Hospital Athlete Health Unit, Izmir, Turkey.

Summary. Background. It is of great importance for athletes to have adequate nutritional knowledge in order to maintain a healthy diet and high sports performance. The aim of this cross-sectional study was to evaluate the nutritional knowledge levels of adolescent athletes in different disciplines and to determine the proportion of athletes at risk of eating disorders. Materials and methods. This study was conducted with 120 adolescent athletes (elite level n=75, licensed amateur n=45) participating in different sports disciplines in Izmir Metropolitan Municipality Sports Club. Data were collected by face-to-face interview method with a questionnaire form including demographic variables, information about the sports branch, eating habits, Sports Nutrition Knowledge Questionnaire (SNKQ) and Eating Attitude Test-26 (EAT-26). Results. The total nutritional knowledge scores of the athletes were 34.4 ± 8.34 (highest score: 78). An eating disorder risk was found in 15.8% of the participants. The mean EAT-26 scores of individual athletes were higher than team athletes and individual male athletes were higher than individual female athletes (p=0.021; p=0.001, respectively). According to the nutritional knowledge score, the age and sports history of the athletes in the 3rd tertile were significantly higher than those in the 1st tertile (p<0.05). Conclusions. In order to increase the nutritional knowledge level of adolescent athletes, comprehensive trainings for athletes, coaches and families of athletes should be given by dietitians. Continuity of trainings and dietitian-athlete communication should be ensured.

Key words. Adolescent athletes, nutritional knowledge level, eating attitude.

Valutazione del livello di conoscenza nutrizionale e dell’atteggiamento alimentare negli atleti adolescenti: studio trasversale

Riassunto. Background. È di fondamentale importanza che gli atleti possiedano un’adeguata conoscenza nutrizionale per mantenere una dieta sana e garantire elevate prestazioni sportive. L’obiettivo di questo studio trasversale è stato valutare il livello di conoscenza nutrizionale di atleti adolescenti appartenenti a diverse discipline e determinare la proporzione di soggetti a rischio di disturbi del comportamento alimentare. Materiali e metodi. Lo studio è stato condotto su 120 atleti adolescenti (livello élite n=75, dilettanti con licenza n=45) appartenenti a diverse discipline sportive presso il Club Sportivo del Comune Metropolitano di Izmir. I dati sono stati raccolti tramite interviste faccia a faccia utilizzando un questionario contenente variabili demografiche, informazioni sulla disciplina sportiva, abitudini alimentari, il Sports Nutrition Knowledge Questionnaire (SNKQ) e l’Eating Attitude Test-26 (EAT-26). Risultati. Il punteggio totale medio di conoscenza nutrizionale degli atleti è risultato pari a 34,4 ± 8,34 (punteggio massimo: 78). Il 15,8% dei partecipanti è risultato a rischio di disturbi del comportamento alimentare. I punteggi medi dell’EAT-26 erano più alti negli atleti di discipline individuali rispetto a quelli di squadra, e negli atleti maschi di discipline individuali rispetto alle loro controparti femminili (p=0,021; p=0,001, rispettivamente). In base al punteggio di conoscenza nutrizionale, l’età e la storia sportiva degli atleti appartenenti al terzile superiore erano significativamente maggiori rispetto a quelli del primo terzile (p<0,05). Conclusioni. Per aumentare il livello di conoscenza nutrizionale degli atleti adolescenti è necessario fornire formazioni complete rivolte agli atleti, agli allenatori e alle famiglie, a cura di dietisti. È inoltre fondamentale garantire la continuità di tali interventi formativi e mantenere una comunicazione costante tra dietisti e atleti.

Parole chiave. Atleti adolescenti, livello di conoscenza nutrizionale, atteggiamento alimentare.

Introduction

Nutrition has a significant impact on athletes’ performance due to its effects on body composition, training adaptation, and recovery1. The foods and fluids consumed before, during, and after training ensure adequate energy availability during exercise, aid in post-exercise glycogen resynthesis, and maximize training adaptation. In adolescent athletes, nutrition is even more critical, not only because of its effects on performance but also due to the rapid growth and development occurring during this period, which influences neurodevelopment, bone mineral density, and chronic disease risk2.

While many factors influence food choices (such as taste, cost, hunger, convenience, etc.), athletes’ knowledge of sports nutrition can affect their dietary behaviors, which may lead to positive or negative outcomes on overall athletic performance. In this context, nutrition education is a crucial strategy to support athletes’ nutrition and health, and it is vital for athletes to learn about nutrition from reliable sources3,4. It is well known that a lack of nutritional knowledge and the spread of incorrect dietary guidance can have negative consequences, particularly for athletes5. Studies have shown that athletes often obtain their nutrition-related knowledge from non-expert sources, such as friends, coaches, family, or the internet, which prevents them from following optimal dietary practices. This frequently results in low energy availability, which increases the risk of Relative Energy Deficiency in Sport (RED-S) and poses long-term risks to health and performance6,7. Previous studies have demonstrated that higher nutritional knowledge is associated with better diet quality and that interventions aimed at improving nutritional knowledge in athletes lead to better dietary behaviors and improved food intake8.

The prevalence of eating disorders is higher among athletes compared to the general population, often emerging during adolescence, a critical period for their sports careers, and is more common in females than in males. Eating disorders lead to low energy availability, adverse health outcomes, and negatively affect athletic performance. Assessing the risk of eating disorders is seen as one of the important steps in promoting healthy eating habits in young athletes and achieving the goal of maximizing athletic performance6,9.

To maintain healthy growth and high performance in adolescent athletes, it is essential for them to develop proper eating habits and meet their increased energy and nutrient requirements. Ensuring that athletes possess sufficient nutritional knowledge becomes a matter of increasing importance. Providing nutrition education to adolescent athletes by a dietitian, as well as assessing their risk for low energy availability and eating disorders, is seen as an effective approach for achieving both health and performance goals. This study was planned and conducted to evaluate the level of sports nutrition knowledge in adolescent athletes engaged in different disciplines, examine the factors affecting their level of sports nutrition knowledge, and identify athletes at risk of eating disorders.

Materials and methods

Study design

The research was conducted using a cross-sectional survey model, one of the quantitative research methods.

Study population and sample

A total of 120 adolescent athletes, aged between 12-18 years, participated in the study. These athletes were divided into two groups: 75 elite athletes (41 females/34 males) and 45 licensed amateur athletes (24 females/21 males), all of whom were practicing different sports at the city’s municipal sports club. The distribution of athletes by sports discipline was as follows: 25 athletes in volleyball (25 females), 17 in judo (11 females/6 males), 17 in taekwondo (5 females/12 males), 15 in handball (14 females/1 male), 13 in ice skating (5 females/8 males), 11 in water polo (11 males), 8 in wrestling (8 males), 6 in tennis (1 female/5 males), 5 in table tennis (4 females/1 male), and 3 in basketball (3 males). Among the elite athletes, 15 individuals (3 females/12 males) were members of national teams.

Ethical considerations

The study received ethical approval from the Ege University Medical Research Ethics Committee with the approval number 20-4.1T/19. All athletes and their parents were informed about the study, and written consent was obtained from those who voluntarily agreed to participate. The data collection process was conducted in accordance with the principles of the 2008 Helsinki Declaration and the Italian Sports Medicine Federation10.

Data collection tools

Data were collected through face-to-face interviews using a questionnaire. In the first section of the questionnaire, demographic variables and information related to the athletes’ respective sports disciplines were queried. The second section included questions about their nutritional habits and sports nutrition knowledge.

Sports Nutrition Knowledge Questionnaire (SNKQ): The scale was developed by Zinn et al. to assess the sports nutrition knowledge of sport-related groups11. The Turkish validity and reliability study of the scale was conducted by Özener et al.12. The Sports Nutrition Knowledge Questionnaire consists of five sub-sections – “nutrients,” “fluids,” “recovery,” “weight control”, and “supplements” – comprising 20 questions and 78 items. Each correctly answered item is scored as “1”, and incorrectly or unsure answers are scored as “0.” A higher score indicates greater sports nutrition knowledge.

Eating Attitudes Test-26 (EAT-26): The EAT-26 was developed by Garner et al. to measure symptoms of anorexia nervosa13. The Turkish validity and reliability study of the scale was conducted by Ergüney-OkumuŞ and Sertel-Berk14. In the Eating Attitudes Test-26, the results are determined by evaluating the sum of the scores of the 26 items. The test yields values between 0-53, with 20 points considered the cutoff score. Scores of 20 and above indicate a risk of eating disorders, while scores below 20 are defined as normal eating behavior13.

Anthropometric measurements

The participants’ height was measured using a stadiometer (Seca 240, Germany) with an accuracy of ± 0.1 cm. Body weight, body fat percentage, and fat-free mass (kg) were measured using a bioelectrical impedance device (Tanita MC-780MA, Japan). Body Mass Index (BMI) was calculated using the formula: Body Weight (kg) / Height² (m²).

Handgrip strength

Handgrip strength (HGS) was measured using a hand dynamometer (Takei Physical Fitness Test TKK 5401 Grip Dynamometer). Measurements were taken while individuals were standing, with their elbow and wrist fully extended. Measurements were repeated three times for both the dominant and non-dominant hands, with a 1-minute interval between each trial, and the averages were recorded in kilograms15.

Data analysis

For the evaluation of qualitative data, numbers and percentages were used, while for quantitative data, means and standard deviations were employed. The normality of the data distributions was checked using the Shapiro-Wilk test. The Sports Nutrition Knowledge Questionnaire (SNKQ) scores of adolescent athletes were divided into tertiles, with the lowest tertile representing the group with the lowest SNKQ scores. The values of other groups were compared to this group. In cases where the assumption of normal distribution was met for numerical variables according to tertiles, the ANOVA test and Bonferroni correction for multiple comparisons were applied. For the comparison of two group means, an independent samples t-test was used for normally distributed data, and the Chi-square test was applied for comparing qualitative data. Statistical analyses were performed using SPSS 26.0 (IBM, USA), and statistical significance was set at p < 0.05.

Results

A total of 120 athletes participated in the study, 75 at the elite level and 45 licensed amateurs. Of the athletes, 54.2% were female (n=65) and 45.8% were male (n=55). The average age of the participants was found to be 16.0 ± 1.56 years, with 83.3% being high school students.

Table 1 shows the results of the athletes’ Sports Nutrition Knowledge Questionnaire (SNKQ) scores and the Eating Attitudes Test-26 (EAT-26) scores.




When examining the nutrition knowledge scale scores, it was found that the athletes scored less than 50% of the highest possible score in all subscales except for “weight control.” The athletes’ total SNKQ score was determined to be 34.4 ± 8.34 points, with elite athletes scoring 34.4 ± 8.89 points and amateur athletes scoring 34.3 ± 7.42 points (p=0.906). When evaluating the subscales, it was found that athletes scored the lowest in the “supplements” knowledge category.

It was determined that 15.8% of the participants were at risk of eating disorders, and although the percentage of individuals at risk of eating disorders was higher among elite athletes, this difference was not statistically significant.

Table 2 presents the evaluation of SNKQ scores and the risk of eating disorders according to sports disciplines and the gender of the athletes. It was determined that male athletes in team sports had significantly higher scores on the fluids subscale compared to female athletes (p=0.015).




While no significant difference was found between the SNKQ scores of team athletes and individual athletes (p=0.499), the mean EAT-26 score of individual athletes was significantly higher than that of team athletes (p=0.021). Additionally, among individual athletes, the mean EAT-26 score of males was significantly higher than that of females (p=0.001).

The athletes’ anthropometric measurements, age, duration of training, hand grip strength, and EAT-26 scores according to the tertiles of SNKQ scores are presented in table 3.




It was determined that the athletes in the 3rd tertile, based on nutrition knowledge scores, had significantly higher age and longer duration of training compared to those in the 1st tertile (p<0.05). No significant differences were found between the participants’ anthropometric measurements and BMI according to their athlete knowledge scores.

Demographic variables, sources of nutrition knowledge, and information about the nutritional habits of the athletes, as well as the distribution of these parameters according to tertiles, are presented in table 4.




It was found that athletes who were continuing their undergraduate education had significantly higher nutrition knowledge scores compared to those in primary education, those who stated that no expert was available on sports nutrition had higher scores compared to those who stated that an expert was available, and those who believed their level of nutrition knowledge was good had significantly higher scores compared to those who believed their knowledge was poor (p<0.05). The majority of athletes who stated that no expert was available on sports nutrition were in the 2nd tertile according to nutrition knowledge scores (39.3%), while those who stated that an expert was available were mostly in the 1st tertile (51.6%) (p<0.05).

Discussion

This study was conducted to evaluate the nutrition knowledge levels and the risk of eating disorders in adolescent athletes. The results show that both elite and amateur athletes have low levels of nutrition knowledge. It was determined that athletes scored the lowest on the subscales of nutritional supplements, recovery, and fluids. Only 15.8% of the athletes had received sports nutrition training, and it was observed that athletes faced difficulties in finding sources of nutrition information. While the risk of eating disorders was found to be higher in elite athletes, the EAT-26 scores of individual athletes were significantly higher than those of team athletes.

Nutrition plays an important role in athletic performance by affecting the athlete’s body composition, training adaptation, and recovery process. Having sufficient nutrition knowledge is a crucial factor in helping athletes make the right food choices. Adequate nutrition knowledge not only increases an athlete’s awareness of eating habits but also helps them practically apply this knowledge when selecting the correct foods or meals, ensuring they meet their energy and nutrient needs16,17. Studies show a positive relationship between nutrition knowledge and diet quality among athletes, and it has been found that football players with higher nutrition knowledge have greater lean muscle mass and maximal power output, as well as better physical fitness and football performance18,19.

Research conducted on both adolescent and adult athletes shows that their nutrition knowledge scores are low. In a study of athletes from different sports disciplines, it was found that adolescent athletes had low nutrition knowledge scores, with athletes correctly answering an average of 43.8 ± 11.4% of the questions and scoring the lowest on the subscales of nutrient knowledge and ergogenic support20. Manore et al. (2017) reported that adolescent football players had low levels of nutrition knowledge (45.6%), with only 6.0% of athletes achieving a score considered sufficient, and no significant gender differences in nutrition knowledge scores were found7. Similarly, a study of professional female volleyball players found that the athletes’ nutrition knowledge scores (45.4 ± 10.0%) were inadequate, and no athlete reached a sufficient knowledge level 21. A study conducted in Turkey, which included professional football players (n=19) and volleyball players (n=24), found that all athletes had poor nutrition knowledge22. In this study, the athletes’ nutrition knowledge scores were also found to be low, consistent with the literature.

It is crucial to ensure sufficient energy, macro- and micronutrient, and fluid intake according to the type of sport performed to enhance performance and maximize functional and metabolic adaptations in athletes. In a study of elite adolescent football players in Turkey, it was found that 93.5% of the athletes had poor diet quality, their available energy levels were low, and they did not consume the recommended amount of carbohydrates23. In this study, 47% of the athletes were found to have low scores in nutrient knowledge. Similarly, O’Brien et al. (2021) reported that elite football players had low scores in both macronutrient (52.8 ± 10.0) and micronutrient (34.2 ± 11.9) knowledge24. A study conducted on female athletes found that their nutrition knowledge scores were low, 30.0% had low available energy levels, 96.3% of those engaging in moderate exercise, and all of those engaging in intense exercise consumed lower-than-recommended levels of carbohydrates25. A weak-to-moderate positive relationship was found between increased nutrition knowledge in athletes and positive nutritional behaviors, diet quality, and energy and carbohydrate intake26,27.

Athletes use supplements to enhance cognitive and athletic performance, speed up recovery after intense training, and prevent nutrient deficiencies. Studies show that 47.8-93.7% of football players, 46.0% of university athletes, and 59.0% of elite athletes use dietary supplements to enhance performance and maintain health28,29. However, a noteworthy point in nutrition knowledge research is that athletes generally score the lowest on the supplement subscale20,21,25,30. In a study of female volleyball players, the supplement knowledge score was found to be 32.1 ± 18.0 points, while it was 39.4 ± 14.0 points for elite male football players and 18.2 points for female football players21,24,25. A study of Turkish national wrestling team athletes found that 30.1% used supplements, while only 28.4% of athletes believed they had sufficient knowledge about supplements8. Similar results were found in this study, with athletes scoring the lowest on the supplement knowledge subscale (16.7%).

Studies evaluating the effectiveness of nutrition education for athletes have shown significant improvements in overall nutrition knowledge, recovery, and hydration knowledge, but no significant improvements in supplement knowledge, suggesting that more comprehensive educational programs on supplements may be needed30,31. Acquiring sufficient knowledge about supplements can help athletes choose the right supplements they need and prevent the risk of violating anti-doping rules due to improper use.

The low nutrition knowledge of athletes in this study may be attributed to the high percentage of athletes who did not receive nutrition education (84.2%) and the lack of access to an expert on nutrition (74.0%). Similar to the literature, 71.0% of athletes who reported having an expert on nutrition said they received information from their coaches8,20,32. This result is expected, given the strong relationship between athletes and their coaches and the trust athletes place in them. However, studies show that coaches’ nutrition knowledge scores are low-to-moderate, with less than 30.0% of coaches understanding the importance of carbohydrates for athletes. Moreover, coaches often rely on questionable magazines and internet sources for nutrition information5,32,33. Improving the nutrition knowledge of coaches could be beneficial.

Eating disorders are a significant mental health issue that negatively affects athlete health. The prevalence of eating disorders in male athletes ranges from 0.0% to 19.0%, while in female athletes, it ranges from 6.0% to 45.0%34. In this study, the overall prevalence of eating disorders was found to be 15.8%. Additionally, it was determined that male athletes engaged in individual sports had higher eating disorder risk scores compared to female athletes, and athletes participating in individual sports had higher risk scores compared to those in team sports. In male athletes, psychological factors, gender role factors, the effects of social media on body image, the desire to have a muscular appearance, the association of muscularity with masculinity, and extreme changes in body weight contribute to the increase in eating disorders35. Individual sports often involve aesthetic and weight-class sports, where lean body mass is important, and weight loss diets are more prevalent. Athletes’ attempts to increase lean body mass and reduce body weight through unintentional energy restriction, especially in weight-class sports, where strict weigh-in rules before competitions are enforced, can lead to rapid weight loss attempts before competitions, increasing the risk of eating disorders34,36.

This research has some limitations. As it is a cross-sectional study, causal relationships cannot be established. Additionally, the athletes’ daily food consumption and dietary habits were not evaluated in detail. Another limitation is that the sample lacked a homogeneous distribution. It is necessary to include similar proportions of male and female athletes from various sports disciplines. Lastly, the evaluation of eating disorders was done using a self-report screening tool rather than a clinical diagnosis.

Conclusion

This study found that athletes have insufficient knowledge of sports nutrition, that they have not received nutrition education, and that they face difficulties in accessing experts who can provide information on sports nutrition. Previous studies have shown that nutrition education programs designed for athletes are an effective strategy. As a result of nutrition education provided by dietitians, significant improvements have been observed in athletes’ eating habits, the number of daily meals consumed, nutrition knowledge scores, and daily energy and nutrient intake levels30,31. Therefore, it is recommended that comprehensive education programs be developed and implemented by dietitians for adolescent athletes, their families, and coaches. Additionally, it would be beneficial to ensure that athletes have continuous access to dietitians for guidance when needed.

Conflict of interest. The authors declare that there is no conflict of interest.

Authors’ contributions. Idea/Concept: MU, CA; Design: MU, RNA, MN; Supervision/Consultancy: MU; Data Collection and/or Processing: MU, RNA, CA, MN; Analysis and/or Interpretation: MU, RNA, CA, EK; Literature Review: MU, EK, RNA; Writing the Article: MU, CA, RNA, EK; Critical Review: MU, EK, MN. All authors contributed equally to the manuscript and read and approved the final version of the manuscript.

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