What is the amount of nutrition that a growing teenager need and what is some good food to eat

I want to be a dietician or a nutritionist.
If you can tell me, I would appreciate it.
I have looked into nutrition at some university’s websites but they didn’t have that listed under any departments. I dunno…. maybe I wasn’t looking good enough.
btw, is the University of York good?

I am looking for a website that can allow me to enter in the ingredients of a recipe and then it will tell me per serving what the nutrition facts are. The only ones I can find have a monthly fee that is very high. Thank you so much!

So I guess what I’m asking is.. am I intaking less sodium than what is stated on the Nutrition Facts for canned tuna when I drain out the water?

What are some cookbooks that give the nutrition information in the book?