In fact I became unable to digest fat while I was omnivore and eating plenty of proteins and fats, even if I was on a "healthy" diet.
Lately I've been taking a lot of soy lecithin and my ability to digest fat is improved indeed, but still have some spasms and loads of mucus when I eat some fats and my already chronically swollen lymphatic nodes seems to become even more swollen.
I plan to try to take a bit of taurin to see if that helps or even just MCT (medium chain triglycerides that requires no bile nor enzymes to be digested).
In fact in our mother's milk we have only 5-7% of proteins and it decreases progressively during the lactation process so I don't know if we really need that much proteins ;). And if you investigate comparative anatomy it is clear that we are more frugivores than omnivores.
But of course I'm staying cautious and not dogmatic. But I know a lot of people that have Lyme disease who would pay thousands of dollars to improve their health as much as I did (and I believe it will still improve a lot thanks to great people like you who have so much knowledge to share and this great forum!)...