People that produce adequate insulin in their pancreas (i.e. not Type 1 diabetic) tend to see a fairly stable blood sugar response to protein. (optimisingnutrition.com)
A few of these beta cells usually survive, but don't produce adequate insulin to process sugars. (sciencenews.org)
Excess protein has minimal effect on blood sugar levels as long as adequate insulin is present. (onnit.com)