Effectiveness of Sports Nutrition Education Based on Self-Determination Theory for Male University Rowing Athletes: A Randomized Controlled Trial

To resolve problems in the dietary life of university athletes, education is essential to enable athletes to change their own dietary behavior. The purpose of this research was to verify the effectiveness of sports nutrition education based on self-determination theory (SDT). The participants were 36 male university rowers. A stratified randomized comparison test was conducted by student year (SDT group and control group). Sports nutrition education was held three times, via an Internet conferencing system. Furthermore, group work over social media was used for the SDT group. Four evaluations were carried out based on anthropometric measurements, a brief self-administered diet history questionnaire (BDHQ), sports nutrition knowledge test (SNK), and treatment self-regulation questionnaire (TSRQ). The results showed no differences between the two groups. However, for the intragroup factor, "Protein", a significant difference was evident in the self-determination theory group (50.0 ± 28.5, 78.6 ± 28.1, 81.0 ± 21.5, p < 0.000, units: %) and improved knowledge (p = 0.002, p = 0.002). And for the BDHQ, the self-determination theory group also showed significant differences and increased their intake of green and yellow vegetables, fruits, and dairy products (159.1 ± 74.2-126.7 ± 70.6, p = 0.009, 306.0 ± 196.2-195.2 ± 146.1, p = 0.020, 257.0 ± 147.0-183.3 ± 167.9, p = 0.040, units: g). In conclusion, sports nutrition education based on SDT improved dietary knowledge and increased food requirements for athletes.