Start with high-confidence diet & nutrition books, then narrow by subgenre or adjacent topics.
The Diet for Teenagers Only
Barbara Schroeder, Carrie Wiatt
Eat Well and Feel Great
Tina Lond-Caulk
No Weigh!!
Signe Darpinian, Wendy Sterling
Strength and Conditioning for Teenagers
Mr Arj Thiruchelvam, Arj Thiruchelvam