Im a pro rugby player,and i to was like you when left school,couldnt put weight on no matter what i ate.then came across a well known old head he advised me to eat everything.all the shit things+eat when your not even hungry and make sure you eat before ou go to bed.found jaffa cakes good.as for training you dont want do to much aerobic training,ie,no long runs no weights that are light and keep away from high reps.What you need to be doing is somthing called power cleans(kings of training}),this can be done using a weight lifting power bar,start off with a light to medium weight.the motion is