The salad bar will help students attain their recommended daily intake of fruits and vegetables. There are nutrients that are only present in certain types of food. Also, vegetables are frequently associated with a healthier life style. By adding those to the menu, there's nothing bad to the students. Quite the opposite. They can attain the recommended intake of whatever is needed (many things better attained through eating vegetables), you add an option to vegetarians, and vegans and it's also a low carb healthy choice for them.