Ive been taking Martial arts for about 6 years now and want to put on some lean muscle. Im 15, very skinny and have no problem with my diet, i have 5 meals a day 3 hours apart and about 4-5 protien shakes a day. I dont gain weight, when i lift, been doing it for about a year. I dont gain, any tips? P.S i weight about 112.