I have celiac so it's absolutely essential that I avoid gluten in its entirety. I have several food allergies as well but none developed post sleeve, they were all pre existing.
The gluten free diet plays nicely with good nutrition post-op. Personally I think we have an advantage over those who are tempted by cookies, pasta, pizza, bread etc because we simply can't eat them. You just have to watch for hidden sources of gluten, like soy sauce, anything with modified corn starch as an ingredient, etc.