Alright, I know there is loads of stuff on this out there, but I figured I would post here any way.

I am 6'2" and 160lb, I have a random genetic thing called Marfan Syndrome that means I am pretty much extremely thin no matter what I do. I have been hitting the weights pretty hard for about 4 weeks now, and I am getting a lot stronger and more toned, but I started out at 159.5 lb and I am now 160.8lb. I am trying to just put on 10lb or so of muscle, I am kind of sick of being perpetually thin, but it just doesn't happen.

It's not just muscle either, I can pack in the calories for months or years and not put on any fat at all, it just doesn't happen.

I have heard people say that how you eat is the key, so I am wondering if any of you guys have any advice on good routines/diets to put on weight for someone like me?

Thanks!