I am a 21 years old boy , i am about 176cm and 56kg . No matter what i do i can't gain weight . . . At the gym they told me to start taking proteins and muscle gain powder but i don't want to start taking this kind of things because my doctor prohibits it . please help . . . My doctor told me that i suffer from metabolic stress which means that every time that i am anxious or sad i just lose weight , despite the amount of food i eat ,and that i should consult a psychiatrist . Can that be true???