Military training in universities is very hard, but there is a big difference between universities and middle schools, and it is very free. Nobody cares about your own food. There is more than one canteen in the school, so you can choose at will. Of course, if conditions permit, you can eat outside the school. However, during military training, the free time at noon is very short (if you want to sleep). If you want to eat well, you must plan your time. There is plenty of time in the evening, so you can have more time to choose where to eat.