Good advice regarding enzymes.
Try using some Pancreatin and/or Protease to help with the protein.
If you’re doing the high fat thing, consider some Lapase to aid that.
And if you’re consuming milk several times throughout the day – especially using it to mix your powders, then take some Lactase.
I can handle milk, but too much of it at once does me in.
Also, if you’re not already, add some fiber to your diet in the forms of vegetables, some fruits, and even a bit of grains (they won’t kill you).
It may be that you’re simply eating more than your body can handle, and that is what’s accounting for the GI distress.
If that’s the case, the above remedies will only help so much.
You may have to scale back your overall caloric intake.