We're worried that he won't get enough protein, and it's a nuisance to try to plan meals around his strict diet. We're not sure how to react. As hard as it is for parents to accept, one of the major developmental tasks of adolescence is to define oneself as different from parents and other adult authority figures. That's a primary way for teens to find an identity all their own. As for your concerns about the impact of a vegetarian diet on his physical health, there probably is no need to worry.
Vegetarian diets can be very healthy and more than adequate in terms of protein.
In fact, nutritionists say that most Americans far exceed the recommended intake of protein, as well as fat, which also is a part of many high-protein foods. If your son eats eggs and dairy products, such as milk, cheese, and yogurt, he probably is getting more than enough protein. Even if he has eliminated dairy products from his diet, foods such as whole grains and beans can provide sufficient protein. As for the mealtime hassles, perhaps a good approach for the whole family would be to affirm and support his choice to be a vegetarian, but not necessarily cater to it. When you cook as you normally would for the rest of the family, let your son eat what he can and then supplement from an assortment of breads, fruits and vegetables.