I take creon 20's, and I was extremely successful in gaining weight with them. When I was very sick, and before I even knew what enzymes were, I weighed 95 pounds. After using them for 5 months...I now weigh 127! I gained 32 pounds in a quck a mount of time, and I didn't drink scandishakes or anything.
As for ultrase, I've never tried them, because I never want to get off of creon. But my brother uses creon 20's also, and hasn't gained a pound in 5 months, and still has digestive issues. SO he might be trying ultrase or atleast another kind of enzyme. So I guess it completely depends on the person's own body. I can't say for you, but I love creon!