Too much protein can indeed kick you out of ketosis, but I haven't had that problem and I have been doing 64% fat 33% protein and 3% carbs.
From Lyle Mcdonald's "The Ketogenic Diet":
"58% of dietary protein will appear in the bloodstream as glucose (3), raising insulin
and inhibiting ketogenesis. Note that the insulin response from consuming dietary protein is
much smaller than that from consuming dietary carbohydrates. Consequently protein must be
restricted to some degree on a ketogenic diet as excessive protein intake will generate too much
glucose, impairing or preventing ketosis."
"a protein intake of 1.5-1.75 grams protein per
kilogram of ideal body weight (ideal body weight was used to approximate lean body mass) would
spare most of the nitrogen loss, especially as ketosis developed and the body’s glucose
requirements decreased."
"Assuming zero carbohydrate intake, during the first 3 weeks of a ketogenic diet a protein
intake of ~150 grams per day should be sufficient to achieve nitrogen balance. Therefore,
regardless of bodyweight, the minimum amount of protein which should be consumed during the
initial three weeks of a ketogenic diet is 150 grams per day.
After 3 weeks of ketosis, as little as 50 grams of protein per day should provide enough
glucose to achieve nitrogen balance."
Hope that helps
