Being a teacher how do you see to ban fasting for their students by some schools?

There has to be a measure on the student extend of physical rigorousness and their ability to perform their regular task at school. If fasting effects the ability of students in performing their usual task then fasting could be avoided during peak days, whilst the intention of the student should also be considered. If any student want to fast, shouldn't be stopped, cause every individual has their own understanding on their ability to perform their task alongside fasting.