Does Crohn's disease prevent building muscle? I'm skinny but I have like the minimal amount of muscle for the weights I use. I've seen people at the gym who I can lift more than but they're a lot bigger than me. Same exercise, same form, but different weights. I eat healthy and try to get a lot of protein in and I work out 4-5 days a week but I can't gain any bulk. I'm not looking to be a body builder but I just want to gain a little weight. I'm 6'0" and 155 pounds.