Contrary to what some people say. Masterbation will not harm you in any way. It helps relieve stress and at orgasm the prostate shrinks when it releases prostate fluid to mix with sperm to make semen. This is helpful later in life to prevent an enlarged prostate.
Gets you prepared for sex; gives you pleasure; relieves stress and tension (some); 'recharges' the batteries; puts hair on your chest. Well, maybe not the last bit.
if u do this everyday, then u are loose important body resources...so eat more healthy food to recompensate.
Some people loose weight some are just fine...it depends.