"What happens if you eat too much protein?
Most Americans eat too much protein. This results in a waste product called ammonia, a very toxic substance. Because it is so toxic, the body protects itself by turning the ammonia into urea, which is then carried to the kidneys and excreted. If you don't eat too much protein, the liver can neutralize ammonia. If you eat too much protein, poor digestion and/or a defect in liver function can result and toxic levels of ammonia can accumulate. Abnormally high levels of urea can also inflame the kidneys and cause back pain."
The above was pasted from the Internet.