For someone with IBD, I would recommend starting with a small amount of NutriBlast like 8-10 oz at best and then slowly increase it to 10-12oz and so on. Be sure to add consistent amount of fiber in your diet so your body doesn't have to overwork to process them.
here is a list of low-fiber foods to include in your diet. Remember that you are having a diet that is not no fiber but just low in fiber. Slowly include these foods and test and try things you know will work and build your repertoire that way. Be careful you do not add too much sugar into your smoothie because excess sugars consumed at one time can cause diarrhea. Add things like seeds and healthy fats in small amounts to avoid excess sugars being introduced to your digestive system.