I used to work at a convalescent home, long before my nutritionist/PT days.
The registered Dietitians were always checking Kidney function. Protein intake was always an issue. I'm thankful that I got to learn at a young age.
I built a respectable physique (and most of you have seen pics of me, so we don't need the comments) on very small amounts of protein.
Study the "controlled" studies, and read the Journals of the AMA and such... here are a few excerpts:
"...as many as 20 million Americans are at risk for reduced kidney function but don't know it. Therefore, people on high-protein diets may be unknowingly damaging their kidneys."
"Knight's findings on high-protein diets are published in the March 18 edition of Annals of Internal Medicine. It's the latest chapter in the ongoing Nurses Health Study..." (controlled study, that is the point here)
"They were tracked for 11 years, and researchers found that those with mild kidney problems who ate a high-protein diet especially protein from meat -- had a faster loss in function."
Please don't take this to mean that eliminating meat from your diet will cure the problem, although eating meat has been shown time and time again to increase the probability.
Here is a statement in regards to the Atkins Diet: "We saw a significantly measurable association in those consuming about 1.3 grams of animal protein for each kilo of body weight," Knight tells WebMD. "That level is not as high as the protein you get from animal sources in the Atkins diet. So clearly a person who is undertaking a high-protein diet such as Atkins should have a kidney function test and carefully be monitored while following this diet."
Thanks to the rags, which are nearly 70% ads for protein supplements, bodybuilders and ESPECIALLY aspiring bodybuilders, believe that the more protein they consume, the bigger they will get.
Well then, why are our bodies so good at excreting Nitrogen?
Excess protein is taxing on the Kidneys. There is no question about it. Yes, if you have "healthy" Kidneys, you can get away with a lot... at first. But here's the rub: Your Kidneys are NOT just dealing with protein consumption, so logically, by the time you are nearing middle-age, your Kidneys are NOT functioning the way they used to because of all the other filtering they have to do. For a bodybuilder, this could be solely from your excess food, supplement and pharmaceutical intake. Make sense?
Your Kidneys will always work to eliminate waste and toxic substances. Once they start malfunctioning, they DO NOT HEAL! This is important to remember. The Liver can heal if "situations" are caught soon enough, but the Kidneys? No.
Try a lower protein intake just for your own empirical data. Just for shits n giggles, whatever. Everyone is so afraid they will "lose size" ~ how would you know unless you try?
I know what's coming next, so I'll let those comments fly. Peace.