I've also read that excess protein consumption is hard on the kidneys and can lead to osteoporosis. However, if your body is using it,
what is excess?
I've done a lot of reading, and my conclusion from it is to get enough dietary calcium (you don't need dairy, you can get it from lots of other sources) and drink water! Regardless of whether or not guzzling water aids in weightloss or is a myth, it's
good for your kidneys. My husband just suffered through two weeks of on and off kidney stone attacks and it's the number one instruction that his doctor stressed: to keep your kidneys healthy, keep them busy
Most bodybuilders that I know eat 40-50% protein. A very few, usually guys who can eat a lot of carbs without getting fat, eat 35%, but that's low to maintain let alone build muscle mass.
Mel