Objectives Despite recommendations to implement nutrition standards in schools, low-nutrient foods and high-energy drinks are still some of the most important challenges for school management and students' purchasing and consumption behavior. In this regard, the aim of the present study is to examine school nutrition policies and their effect on the promotion of low-nutrient foods in the context of sports advertising. Methods A partial least square technique with SmartPLS 3.0 and bootstrapping with 500 resamples was used to examine the effect of food marketing on school nutrition policies and students' nutritional involvement. Online surveys were done through The Iranian Educational Network of students and measured on a 5-point Likert scale. The survey questionnaire consisted of 3 scales to measure the following: school nutrition policies, advertising of low-nutrient foods, and student nutritional involvement. Results Results from a sample of 382 Iranian high school students revealed that low-nutrient food advertising has a significant effect on student consumption, and the greatest overall effect on students' nutritional involvement. School nutrition policies were affected by media, endorsement, and the environmental advertising, whereas school financial capabilities had the greatest direct effect on students' nutritional involvement. Conclusions These findings suggest that advertising through sports media plays a mediating role in school nutrition policies and student nutritional involvement. Policy changes to restrict food marketing for young people must include both television and non-broadcast media.