I've never seen that part of the explanation. I don't think it was in the Eating for IBS book, or else I didn't read it entirely just assuming it was the fat content.
The time I started extreme C was when I first started eating this bread with egg yolks! I only have a piece or 2 every other day. But maybe that's enough. I must do some experimenting for sure.
I eat egg white omelettes every other day. It seems from what Heather says, this would not cause the constipation. And I can keep eating the egg white omelettes. Is that how you would interpret this info?