How bad is a high protein diet for your kidneys. i am taking 2 grams per lb of body weight and doing heavy lifting.?

Can cause problems: Megadoses of protein can be harmful to the kidney, and in extreme cases can lead to renal failure. It's important to note that this occurs because all that extra protein is unnecessary and is excreted, in stool but also in urine as Amino Acids (or whole proteins if kidney is damaged). Huge amounts of protein don't build more muscle- diet rich in veggies and lean protein is just as good or better.

OK if kidneys are OK: Normal kidneys should be able to handle without major problems. Need to rule out any underlying CKD or proteinuria. Also important to exclude liver disease and with any underlying metabolic diseases.