Being a devoted weight trainer for many years now I often hear the well intentioned warning to not eat too much protein because it damage my kidneys. On social media, this topic often comes up where the dangers of too much protein is espoused. For once, I truly wish that someone could give me a definitive answer as to how much exactly is too much protein for the kidneys to handle and what is your scientific evidence to back your opinion up. Not a single person, including my personal physician has ever been able to give me a definitive answer. Want to know why this is? It is because it is a opinion only and not a proven theory. There is a tremendous amount of flawed thinking behind these opinions which often come from folks with an agenda such as some Vegan web sights where they are simply trying to turn people away from eating meat and any other food products which come from animal sources.
Now, what is protein and how does our body use it; Protein is an important component of every cell in the body. Hair and nails are made mostly of protein. Your body uses protein to build and repair tissues. You also use protein to make enzymes, hormones, and other body chemicals. Protein is an important building block of of bones, muscles, cartilage, and blood. Along with fat and carbohydrates, protein is a macronutrient, meaning that the body needs relatively large amounts of it. Unlike fats and carbohydrates, the body does not store protein, and therefore has no reservoir to draw on when it needs a new supply. (1)
There are arguments that people who eat too much protein run the risk of kidney disease. It is said that when you eat too much , more nitrogen is taken in than required which is supposed to place a strain on the kidneys which must expel the excess through urine. I get that people with kidney disease need to watch there protein intake, but they need to watch everything they place into their bodies, not just protein. And this is especially true of anyone who is on dialysis treatments. But again, I have searched high and low, and still fall short on the answer of how much is too much. Please, someone do a scientific report and let the world know the answer to where the threshold lies as to how much is too much.
I am as health conscious as they come and do not want to damage such an important internal organ. Our kidneys do so much; they remove wastes and extra fluid from our bodies. They also remove acid that is produced by the cells of your body and maintain a healthy balance of water, salts, and minerals such as sodium, calcium, phosphorous and potassium in your blood. Without this balance, nerves, muscles and other tissues in your body may not work normally. Your kidneys also make hormones that help control blood pressure, make red blood cells and keep your bones strong and healthy. (2)
I live my life as healthy as they come. I have researched this topic of how much protein is too much pretty extensively and have yet to find any medical organization that gives a definitive answer to this question. For a healthy individual, .6 gram per pound of body weight is usually recommended for women while .8 gram per pound of body weight is recommended for men. Those numbers go up for those of us who weight train or who are involved in strenuous athletic activities. Women who strength train should eat between .8 to 1 gram per pound of body weight and men 1 to 1.25 grams per pound of body weight in order to build muscle. I personally eat up to 2 grams of protein per pound of body weight daily and my blood labs are perfect.
I would truly like to know the backgrounds of the subjects studied where the conclusions have come that their kidneys were harmed by too much protein. Were any of them the types who drank little water, yet drank large amounts of of soft drinks instead? Were any of them body builders who are especially known to consume large amounts of protein? If so, there are a couple of factors to consider. Teen age boys new to strength training are known to drink massive amounts of protein drinks in order to gain size. The problem is, many of them are drinking protein shakes known as mass gainers which are very calorically dense and will cause a user to pack on a lot of body fat which can skew blood labs. Young men who are involved in body building are also known to use massive amounts of supplements both legal and illegal. Every nutrition store out there sells what are known as “Stacks” of supplements to take together to increase strength and size. These supplements can be harmful when misused. I wonder how many parents believed their son only used protein and did not know about supplement stacks when Little Johnny was being autopsied. And then there are the gray area drugs known as SARMS (Selective Androgen Receptor Modulators) which can be bought from supplement stores and online. How many with kidney failure ever admitted to using them? And of course, there are the illegal steroid users who jack up their bodies. If they are competitive, they will rarely admit to using a performance enhancing drug which might have caused problems with their internal organs.
I am pragmatic in how I view different issues. I have taken great interest in this topic. I believe there are certainly people who consume large amounts of protein who develop kidney problems. However, I also do not believe that correlation equals causation all the time. There may be a correlation of people with bad kidneys who consume lots of protein, yet there are certainly going to be other possible factors which may contribute to their problems too. In closing, if anyone can show me a definitive amount of protein which is too much, please do. But also be ready to cite legitimate sources. Until then, I will remain on my high protein diet while keeping my complex carbs fairly low.
(1) WbMD, The Benefits of Protein
(2) National Institute of Diabetes and Digestive and Kidney Diseases