• Myths Surrounding High Protein Diet Safety

    Posted In: News  /  Posted On: 08.16.12

    Ever since the day I first touched a weight I’ve heard all the myths surrounding weightlifting and bodybuilding.  I’m sure you’ve heard some of them at one time or another as well.  Everything from “weightlifting stunts your growth” to “lifting weights shrinks your penis” to “you know creatine is a steroid, right?”  While many myths are easy to write off as being ridiculous, the myths surrounding protein intake are more widespread.  Many people have the impression that high protein diets are unhealthy.  Kidney damage, liver damage, heart disease, osteoporosis and others have all been blamed to some degree high protein intakes.  What is even more shocking is that many in the medical and scientific community have accepted this as fact without hardly any evidence.  So what does the actual research say?  Is protein going to kill us?

    “High protein intake can damage your kidneys!”

    The kidneys are involved in nitrogen excretion, and thus it has been theorized by some that a high nitrogen intake (protein) may cause stress to the kidneys.  Additionally, low protein diets have typically been recommended to people who suffer from renal disorders.  To conclude that a high protein intake damages the kidney is very tenuous however.  A study examining bodybuilders with protein intakes of 2.8g/kg vs. well trained athletes with moderate protein intakes revealed no significant differences in kidney function between the groups.1  Additionally, a review of the scientific literature on protein intake and renal function concluded that “there is no reason to restrict protein in healthy individuals.”  Furthermore, the review concluded that not only does a low protein intake NOT prevent the decline in renal function with age, it may actually be the major cause of the decline!2  This conclusion is supported by the fact that low proteins diets have NOT been shown to be beneficial for blunting the progression of chronic renal failure.3

    “High protein intake can contribute to liver disease.”

    There is absolutely no evidence to support the notion that a high protein intake is detrimental to the liver.  Protein is needed to repair liver tissue and for the conversion of fats to lipoproteins so that they may be removed from the liver.4  Amino acids are also the main fuel source for the liver.  Additionally, in alcoholic liver disease a high protein diet has been shown to improve liver function and reduce mortality and BCAAs are also being investigated as a treatment for liver disease.5,6  It could even be postulated that in the case of liver damage/disease a high protein diet may be required in order to repair liver tissue damage and to aid in recovery.

    “High protein intake causes bone loss.”

    Another major knock on high protein diets is that they cause increased calcium excretion.  Thus a hypothesis stands that over a long period of time, a high protein diet may contribute to the onset of osteoporosis.  However, the real world data is somewhat equivocal as early studies that demonstrated calcium loss due to increased protein intake.7  However, there is some recent evidence suggesting that an increase in dietary protein may not cause an increase in calcium excretion at all and an increase in dietary protein may potentially improve bone mass in the elderly.8  Moreover, several epidemiological studies actually found a positive association between protein intake and bone mineral density.9,10  Furthermore, low protein diets may actually have a detrimental effect on bone.  Although low protein intakes cause less calcium to be excreted, they also cause a reduction in calcium absorption through the intestine.11  The net effect is a DECREASE in calcium balance due to a reduction in protein intake.  Thus, while increasing protein may increase calcium excretion, there is no evidence that the increased calcium lost in urine is from bone, and the overall net calcium balance is either unaffected or actually improved by a high protein diet.

    “High protein diet cause heart disease.”

    Much has been written about the association of high intakes of red meat with heart disease, but these associations are from the fact that 1) red meat is typically high in fat 2) people who eat high amounts of red meat are less likely to consume adequate fiber and 3) people who eat large amounts of red meat also typically exercise less than other people.  If you statistically correct for those three confounding variables you find that red meat has virtually no association with heart disease.  Not only does the scientific literature not support the statement that a high protein diet may have a negative impact on the heart, it actually supports a high protein diet for the prevention of heart disease.  Research suggests that replacing dietary carbohydrates with protein may decrease the risk of heart disease.12  This is supported by the fact that replacing dietary carbohydrates with protein improves blood lipid profiles by decreasing triglyceride levels and increasing HDL (good) Cholesterol levels.13  Furthermore, metabolism of carbohydrates and/or fats increases the production of free radical levels to a much greater degree than the metabolism of protein.14  High levels of free radicals are thought to accelerate the formation of atherosclerosis, the major cause of heart disease.15

    “High protein intakes can increase the risk of diabetes.”

    This one is just completely false.  In fact, a high protein diet may be beneficial for combating obesity and diabetes.  Recent research indicates that a diet consisting of 30:40:30 (protein:carbs:fats) was superior to the food guide period diet of 15:55:30 in maintaining glucose homeostasis, increasing insulin sensitivity, and improving glucose control in normal people and those suffering from type II diabetes.13,16,17  This same high protein diet has also been shown to be superior to the food guide pyramid diet for weight loss.  Furthermore, subjects consuming the high protein diet maintained more lean muscle tissue and lost a greater proportion of fat than those subjects consuming the high carb diet.17  Several investigators have also reported increased satiety with the high-protein diet compared to a control high carb diet.18,19  In summary, a high protein, lowered carbohydrate diet is superior to a high carb (i.e. food guide pyramid) diet in promoting fat loss, muscle maintenance, and appetite suppression.

    You can have your high protein cake and eat it too!

    Much of this evidence I have presented not only contradicts statements that high protein diets are unsafe, but supports high protein diets in the prevention/treatment of heart disease, diabetes, and obesity.  Those are three of the world’s biggest killers, and a high protein diet may be the key to reducing the incidence of all of them!  Perhaps the American Heart Association and the rest of the high protein naysayers would be best served to get the facts first, rather than making statements with little to no scientific support.  So next time someone tells you that a high protein diet is bad for you, slide this article on over to them, then sit back and enjoy your next high protein meal.


    1.  Poortmans JR, Dellalieux O. Do regular high-protein diets have potential health risks on kidney function in athletes? Int J Sports Nutr 2000;10:28-38.

    2.  Walser M. Effects of protein intake on renal function and on the development of renal disease. In: The Role of Protein and Amino Acids in Sustaining and Enhancing Performance. Committee on Military Nutrition Research, Institute of Medicine. Washington, DC: National Academies Press, 1999, pp. 137-154.

    3.  Klahr S, Levey AS, Beck GJ et al. The effects of dietary protein restriction and blood-pressure control on the progression of chronic renal failure. N Engl J Med 1994;330:877-884.

    4.  Navder KP, Lieber CS. Nutrition and alcoholism. In: Bronner, F. ed. Nutritional Aspects and Clinical Management of ChronicDisorders and Diseases. Boca Raton, FL: CRC Press, 2003, pp. 307-320.

    5.  Mendellhall C, Moritz T, Roselle GA et al. A study of oral nutrition support with oxadrolone in malnourished patients with alcoholic hepatitis: results of a Department of Veterans Affairs Cooperative Study. Hepatology 1993;17:564-576.

    6.  Suzuki K, Kato A, Iwai M.  Branched-chain amino acid treatment in patients with liver cirrhosis.  Hepatol Res.  2004 Dec;30S:25-29.

    7.  Ginty F. Dietary protein and bone health. Proc Nutr Soc 2003;62:867-76.

    8.  Dawson-Hughes B, Harris SS, Rasmussen H et al. Effect of dietary protein supplements on calcium excretion in healthy older men and women. J Clin Endocrinol Metab 2004;89:1169-73.

    9.  Geinoz G, Rapin CH, Rizzoli R et al. Relationship between bone mineral density and dietary intakes in the elderly. Osteoporos Int 1993;3:242-8.

    10.  Cooper C, Atkinson EJ, Hensrud DD et al. Dietary protein intake and bone mass in women. Calcif Tissue Int 1996;58:320-325.

    11.  Kerstetter JE, Svastislee C, Caseria D et al. A threshold for low-protein-diet-induced elevations in parathyroid hormone. Am J Clin Nutr 2000;72:168-173.

    12.  Hu FB, Stampfer MJ, Manson JA et al. Dietary protein and risk of ischemic heart disease in women. Am J Clin Nutr 1999;70:221-227.

    13.  Layman DK, Boileau RA, Erickson DJ, Painter JE, Shiue H, Sather C, Christou DD.  A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women.  J Nutr. 2003 Feb;133(2):411-7.

    14.  Mohanty P, Ghanim H, Hamouda W et al. Both lipid and protein intake stimulates increased generation of reactive oxygen species by polymorphonuclear leukocytes and mononuclear cells. Am J Clin Nutr 2002;75:767-772.

    15.  Paolisso G, Esposito R, D’Alessio MA, Barbieri M.  Primary and secondary prevention of atherosclerosis: is there a role for antioxidants?  Diabetes Metab. 1999 Sep;25(4):298-306.

    16.  Layman DK, Baum JI.  Dietary protein impact on glycemic control during weight loss.  J Nutr. 2004 Apr;134(4):968S-73S.

    17.  Layman DK.  Protein Quantity and Quality at Levels above the RDA Improves Adult Weight Loss.  J Am Coll Nutr. 2004 Dec;23(6 Suppl):631S-6S.

    18.  Hill AJ, Blundell JE. Composition of the action of macronutrients on the expression of appetite in lean and obese human subjects. Ann N Y Acad Sci. 1990;580:529–31

    19.  Stubbs RJ, van Wyk MC, Johnstone AM, Barbron CG. Breakfasts high in protein, fat or carbohydrate:  effect on within-day appetite and energy balance.  Eur J Clin Nutr 1996;50:409–17

    • James Baggett

      Just a question more than a comment….I was on a steady weight training and exercise regimine and still am. About two years ago I was on a high protein diet and added protein shakes to them. I ended up in the hospital shortly after adding the drinks with some kidney stones. Was it the protein mix responsible? Or another factor?
      I’d like to start a supplement plan this coming fall while at college…

      • http://www.biolayne.com Layne Norton

        I’ve yet to see evidence that high protein intakes cause kidney stones.

        • Chris

          Hi Layne,

          Great article on protein, especially since many of us have kidney disease in our families. I checked out your reference but did not see any current references for 2010-2013. What is the current research showing? What peer reviewed journals do you recommend that Bodybuilders follow?

          Thanks for the insight,


      • Kent Trivette

        I’ve had kidney stones several times and protein intake had nothing to do with it. It was probably a coincidence and you were about to have them anyway. Two key factors to cause kidney stones are 1) being dehydrated and the kidneys not being able to flush calcium out properly, (2) the caramelization process used in sodas (the only sodas without carmelization are completely clear. Eat your protein, your muscles and metabolism need it.

      • Lorin Bosoc

        It’s not the protein, it’s because you’re not drinking enough water. Simple as that.

    • Benson Cheek

      Another great article Layne! Appreciate all the time you have invested in writing these.
      It’s always enjoyable reading your work. Keep it up my man!

      • http://www.biolayne.com Layne Norton

        you are welcome!

    • David

      Great article, thanks layne!

      • http://www.biolayne.com Layne Norton

        thanks for reading!

    • Eric
    • Faiqanuar

      Very good article indeed Layne! Thanks !

    • Antti

      I recently watched a BBC Horizon documentary, where they argue that high protein diet causes cancer, diabetes and accelerates aging. To summarize, protein increases IGF-1 levels pushing the cells to divide faster. This then prevents the body to repair itself when diseases start to develop.

      These are the scientists interviewed,


      Here a link to the part of the video where they discuss protein and IGF-1

    • tom

      will creatine suppliment give good result and increase the weight lifting capacity?
      what is the right dose?

      • http://www.biolayne.com Layne Norton

        In most people creatine has a modest but significant effect on improving strength and performance. 5g creatine monohydrate per day is more than enough

        • http://www.facebook.com/profile.php?id=100001696177047 Toms George

          thank you, doc…

    • Mark Smith

      Layne, people have always been telling me ( since I eat so much chicken) that all of the estrogens they feed the chickens are going to transfer over to me. I can only help but laugh. Have you come across this? In the end, I wouldn’t mind having a nice set of boobs to cop a feel off of once in a while lol

      • http://www.biolayne.com Layne Norton

        this is nonsense, the hormones fed chickens are destroyed during the harvesting, cooking, and digestion processes… there is zero evidence they make it into your food supply that I’ve seen.

    • http://www.exerciseequipmentfanatic.com michael h

      great article layne, you are like the mythbusters of fitness BS. what about long term effects? it seems like that first study with the body builders and athletes was only over a short term (7-days).

      was wondering your thoughts on long term effects? the longer term study they site in Int J Sports Nutr 2000;10:28-38 is for older women, and then it doesn’t really say how much protein intake they had.

    • Jodie Ringin

      Thanks for a very informative read! There’s a lot of bad stuff going on out there thanks to a poorly informed media fed world!

    • https://twitter.com/SamJBooth Sam Booth

      I think its rediculous that the government think this. Probally a reason why they keep putting the Tax higher in the UK. Just to make more money, I thought they wanted people to be healthier but instead they are making it more expensive! Great read.


      layne i think you rock i loved the article. i’m new to bodybuilding and i’m enjoying reading and watching your video’s keep up the good work i think your amazing.

    • http://drinknatureswater.com Bill Mabry

      From what I have heard from your video’s there is some truth in them. However, I have to disagree with you on the information on protein. I have been in the fitness, health industry for 30+ years, does that mean I know a lot yes, however I’m still learning something new about the human body on a daily bases. First, all proteins are not the same just like all waters are not the same, not all wines are the same. There is research on how much protein your body actually needs to sustain itself in a homeostasis environment. There is also a lot of research on how important utilization and how much of the nutrients are we really absorbing, and that is where my focus has been. All nutrients all supplements need some type of transport system to get it into the cells, and of course, we all know that is water, so you have to have the right type of water and you need to
      understand the science behind water. You also have to look at types of protein and utilization. I have done my own research on that, on my self. My wife and I have both competed in bodybuilding and we know how important recovery is for building muscle mass. The faster you recover after a hard training session the faster you can get back into the gym. You made a comment about the China Study, there is a lot of truth to that and as you mature and keep an open mind you will understand the complexity of the human body and what it will recognize as good food from bad food. You cannot fool the human body it knows good food from bad food. From my studies it is all about acid/alkaline imbalance, you fix that, you will live a long healthy life.

      • http://www.biolayne.com Layne Norton

        please cite said research sure. And come strong, don’t send me a link to articles on a silly website. Send me RESEARCH. Don’t talk about it… SHOW ME THE RESEARCH!

    • Jon

      Hi Layne,

      Thanks for the great read. I recently donated a kidney, and am looking to get back in the gym as soon as possible. The dietitian, surgeon, nephrologist, and post-care nurse have all given me differing opinions on how much protein I can safely ingest now that I only have one kidney remaining. Their answers have ranged from 105g max per day to as much as I want. I tend to put the most stock in what the nephrologist said, as I believe he would understand kidney function and health better than the others. His recommendation fell somewhere in the middle, around 200g per day.

      My question to you, is whether or not these recommendations in your article change due to my situation. I have been lifting for over 10 years, have had a protein intake as high as 450g per day, and my kidneys were still in perfect health to donate. My remaining kidney will eventually enlarge to make up for the other, but will never operate at the capacity of having 2 healthy kidneys. Have there been any studies showing the effects of high protein on people with a single kidney?

      Thanks for your help!

    • Shiva

      Hi Layne,

      Like others I too am impressed with your work specially the research based writing.
      I wanted to know your take on “egg white powder”. Do you think it is better than other sources ??

    • historian3x

      Hi Layne, I realize this is a older article and I apologize for asking this a little late, but to clarify what you said with regards to the safety of HP diets, are you concluding this from a stance of to short term(i.e. months to a year) or do you believe it doesn’t matter in duration(i.e indefinitely) of length that one follows a HP diet. I ask because most studies are short term and everyone says “we don’t know the long term effects” and I can’t get a straight answer.

    • Pure Science

      Full of holes… You think you have answered the question?

      Not even close…. A person in renal failure… is not a good indicator… or a test subject for reduced protein intake.

      And a study short term… of high and low… isn’t the key…. Millions… of test subjects over years… is the key…

      and … then we will have definitive answers.

      YES the evidence on both sides… is still WEAK…. either pro or con…

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    • Laure Scollard

      Relatively little evidence has been gathered regarding the effect of long-term high intake of protein on the development of chronic diseases.^-‘”

      View all of the most up-to-date blog post on our own internet site http://www.healthmedicinebook.comuo

    • http://www.TheCarbNiteSolutionReview.com Ahmad

      Currently it looks like BlogEngine is the best blogging platform available right now.
      (from what I’ve read) Is that what you are using on your blog?

    • Maneesh

      I have been lifting weight since last six months. I eat 8-12 whole eggs everyday. Is it safe?

    • Denise

      I was just wondering if it’s true that Americans are consuming too much protein, specifically animal proteins, that, especially in our middle ages, apparently cause cancer. Some study between the US and Italy was cited in regards to this, however, I hadn’t seen the study cited anywhere, just an article, and highly contradictory, at that: low-protein in middle ages, increase to high protein past 65. What??

      Again, just curious… some keyboard warrior attmepted to school me with this drivel. All I can think of that may be cancer-causing is the ridiculous sugar consumption and GMO/chemical-ladened foods.

      Thanks for any insight, sir!

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