For the first time here at the ISSA, we’ve decided to do a follow-up article addressing the best questions we received in our comments section and on our social media platforms. We received many great responses to the “Protein Myths” article that we published not too long ago, and along with that response, more great questions surfaced that we wanted to answer in more depth.Read this post
How Much is Too Much? Protein Myths Busted
You’ve heard that too much protein can be bad for your health, but is it true? Get the real answers, based on research
As a trainer, you’ve probably heard it all when it comes to protein:
Too much protein will destroy your kidneys.
A lot of protein makes your bones weaker.
Only professional bodybuilders need that much protein.
There are myths galore about protein, from how too much is damaging to your body to the idea that protein isn’t that important unless you’re a serious lifter.
The truth about protein is that it is misunderstood
Protein is an essential nutrient that plays a huge role in helping to keep you healthy and is essential to building muscle mass. And those statements about bone strength and kidney function? Totally untrue, in fact the opposite is true.
Protein actually plays a role in preventing osteoporosis and strengthening bones. And there is no evidence that a healthy person will get kidney damage from a typical high-protein diet.
You probably already know some of this, but you need to be able to convince your clients and people who ask you for fitness and nutrition advice. Tell them why getting enough protein is so important:
- Protein builds muscle mass
- Adequate protein is needed for post-workout recovery
- Protein in the diet supports fat loss
- Protein is important for a healthy immune system and connective tissue
- Insufficient protein skews body composition
So, we know protein is good and necessary, especially if you’re active. But can there be too much of a good thing?
Sure, too much of anything is always possible, but with protein, that danger level is much higher than most people realize.
To convince the people that they are definitely not eating too much protein, and in fact that they might even need more, let’s take a look at the myths about protein and bust them wide open.
Protein Myth #1 – A High-Protein Diet Damages Your Kidneys
Think of the kidneys as our body’s water filter. They get rid of unneeded substances, metabolites, and other waste from the body.
And yes, kidneys play a crucial role in metabolizing and excreting the nitrogen byproducts from protein digestion. But, this doesn’t mean that eating a lot of protein will overtax your kidneys.
One reason this myth has perpetuated is that research has shown a high-protein intake can increase how hard kidneys work—for people who already have chronic kidney disease and damaged kidney function.1
Multiple studies concluded that healthy individuals will NOT develop kidney disease or impaired kidney function from increased protein intake. 2,4,7
To get into a little more detail, what the researchers found was that increased protein intake does change how your kidneys function, leading to hyperfiltration—but this isn’t a bad thing.
Think about people who have donated a kidney. That one kidney left over suddenly has to handle more protein. If higher levels of protein damaged healthy kidneys, we would see it in donors. But we don’t. That one kidney just adapts and donors have no increased risk for kidney disease.
Need some more evidence?
Researchers have found that bodybuilders and other athletes who consume high protein diets are also not at a greater risk for kidney damage or disease.7 These people may consume more than 2 grams of protein per kilogram of bodyweight, much more than the average person eats per day.
Protein Myth #2 – Too Much Protein Weakens Your Bones
The idea of protein leading to weaker bones comes from the fact that protein increases the acidity of the body, and that this causes calcium to leach from the bones to counteract it.
Excess acidity has been found to lead to bone weakness, but protein is not the culprit. 3
As a matter of fact, protein in the diet has the opposite effect: it strengthens bones. Increased protein in the diet leads to greater levels of insulin-like growth factor-1, better calcium absorption, and more vitamin D.
All of these effects act to strengthen the bones.
And that’s not all. More protein in the diet, combined with weight training increases muscle mass and strength. This is especially important as we age and naturally start to lose muscle mass. Having more muscle is associated with greater bone density.
So How Much Protein Do You Actually Need?
Now that you explained to the naysayers that more protein is better, how much should you recommend?
Currently the FDA recommendation is for 50 grams of protein per day for both men and women. This is a very general recommendation and isn’t accurate for people who are really active.
For people who work out, for athletes and trainers, more protein is necessary to build muscle and aid in recovery.
Personally, I have not found any studies showing that 2 grams of protein per kilogram of body weight is harmful - although I'm still doing my own research on that intake (if you find any, please leave the link or study in the comments section!).
For anyone who is moderately to extremely active, 2 to 3 grams of protein per kilogram of bodyweight is a good general guideline.
This means that for an athlete who weighs 175 pounds (this is about 80 kilograms), protein in the range of 160 to 240 grams per day is reasonable, much more than the FDA recommendation.
While helping people figure out how much protein to eat, it is important to keep in mind that too much protein can be harmful for anyone with kidney disease or kidney damage.
Unfortunately, chronic kidney disease is known as a “silent disease.” Symptoms are hard to detect, but you can get some simple tests done at your doctor’s office to find out if you have any issues with your kidneys.
A serum creatinine level test or a urinary dipstick test for proteinuria will tell your doctor if you have any kidney damage and whether or not you need to be careful about protein intake. For anyone with kidney damage, an intake of about 0.6 grams per kilogram is recommended. 6
Now you have the myth-busting facts to go help your clients, friends, and family make better choices about protein—go forth and change some minds.
- Friedman, A.N. High-protein diets: potential effects on the kidney in renal health and disease. Am. J. Kidney Dis. 44(6): 950-62, 2004.
- Juraschek, S.P., L.J. Appel, C.A.M> Anderson, and E.R. Miller III. Effect of a high-protein diet on kidney function in healthy adults: results from the OmniHeart trial. Am. J. Kidney Dis. 61(4): 547-54, 2013.
- Kerstetter, J.E., A.M. Kenny, K.L. Insogna. Dietary protein and skeletal health: a review of recent human research. Curr. Opin. Lipidol. 22(1): 16-20, 2011.
- Landau, D. and R. Rabkin. Effect of nutritional status and changes in protein intake on renal function. In: Nutritional Management of Renal Disease (Third Edition), Chap. 13, J.D. Kopple (Ed.) Academic Press, 2013, pp. 197-207.
- Levey, A.S., S. Adler, A.W. Caggiula, B.K. England, T. Greene, L.G. Hunsicker, J.W. Kusek, N.L. Rogers, and P.E. Teschan. Effects of dietary protein on the progression of moderate renal disease in the modification of diet in renal disease study. J Am. Soc. Nephrol. 7(12): 2616-26, 1996.
- Levey, A.S., S. Adler, A.W. Caggiula, B.K. England, T. Greene, L.G. Hunsicker, J.W. Kusek, N.L. Rogers, and P.E. Teschan. Effects of dietary protein on the progression of advanced renal disease in the modification of diet in renal disease study. Am. J. Kidney Dis. 27(5): 652-63, 1996.
- Martin, W.F., L.E. Armstrong, and N.R. Rodgriguez. Dietary protein intake and renal function. Nutr. Metab. 2:25, 2005.