Very interesting.
My diet is around 5% carb, 20% protein, 75%fat.
When my protein is higher, my BG levels after 2 hrs eating are not detectably higher, but they do not drop back so quick. For example I may be 4.8 before eating, 5.6 2hr after then, with a high protein meal I could well be 5.8 4hrs after. So I have to watch my protein, and I find the more fatter the meat, the quicker my BG levels drop (because there is less protein and more fat), thus I now try to avoid eating chicken breast... To much protein, not much fat.
I don't think my protein input equates to 50% carb, I think much lower, maybe 33% carb or even 20%. That's just me.