I had physically violent reactions to whey protein post operatively. I tolerated them pre-op but not post-op. I switched protein sources to egg white Protein Powder and they are tremendous. No GI upset, no gas/bloating, no nausea. Great taste, no chalky aftertaste. The brand I use has 23g protein per scoop. Vanilla, chocolate, strawberry. I have a fruit shake in the morning and at night. Best decision I have made.