How can I gain weight with Crohn's Disease?

Introduce more starches to your diet...like pastas and rice. Also eat meats with lower fat content, which will help you gain weight without aggravating your stomach, such as chicken and fish, or ground turkey instead of ground beef. Drink lots of milk, but if you're lactose intolerant, drink lactaid. It's high in calories and protein, so you can put on healthy weight. I've only had crohn's for a few months and I've gained back most of my weight by eating the above foods... good luck!