Haha, thanks for all the replies

Somewhat comforting to know.
Asked dad, he doubts I would have worms too.
I guess I just can't put on weight. Speaking of genetics here, he's lightweight too, and he eats a whole lot of food (leftovers, since usually the family can't always finish).
thingstodo : i doubt i'm burning that much fat, because I hardly have any to begin with. But I guess the increased metabolic rate with going to the gym explains it
Martian : I'm not going for a buff build anyways, just lean muscle would be fine with me.
Once again thanks for the replies

Paranoid me. :*)