Protein is one of the three main macronutrients (along with carbohydrate and fat) that contribute a significant portion of calories towards our total daily energy intake (TDEE).
They are composed of various amino acids, which serves as the “building blocks” the body uses to build and repair muscle and other tissues (structures) in the body.
Beyond their role in supporting the structural integrity of the body, protein (amino acids) are also used to synthesize enzymes, neurotransmitters, hormones, and hemoglobin as well as support immune function.
And, protein can also be used for energy; however, it’s not the first (or even the second) choice for energy production. The reason for this is that metabolizing protein is very expensive for the body to digest, and then even more energy is required to convert it into glucose (via gluconeogenesis).
Research has highlighted the importance of dietary protein regarding health, wellness, and immune function. Individuals who engage in resistance training also have considerably higher protein requirements due to the additional stress demands they impose on their bodies.[1]
Despite the importance protein plays in everyday life, there are (unfortunately) many myths surrounding its consumption and subsequent effects on the body.
Today, we look at 4 protein myths to stop believing.
Top 4 Protein Myths to Stop Believing
Protein Myth #1: High Protein Diets Are Bad for Your Kidneys
Without question, the biggest myth surrounding protein is that consuming too much will wreak havoc on your kidneys.
This myth started nearly 100 years ago when a study by Jackson et al. found that high protein diets resulted in moderate to severe renal damage in rats who were missing a kidney.[2]
Of course, if social media was around in 1928 when the study was initially published, the caption would have read:
“High protein diets are bad for kidneys” instead of the more honest (less click-baity) title: “high-protein diets are harmful to rats when they are missing a kidney.”
Based on this one study (in rats), the foundation was laid for the belief that high-protein diets are detrimental to an individual’s kidneys, and that belief has continued to plague the fitness industry ever since.
But, when you look past the hype and fear-mongering and do a little bit of searching, you’ll come across a vast array of studies, literature reviews, and meta-analyses that dispute the notion that high-protein diets are harmful to a person’s kidneys.
More specifically, every single one of these studies shows that in otherwise healthy individuals, high-protein diets do NOT impair kidney function, negatively impact glomerular filtration rate (GFR), or hurt electrolyte balance.[3-10]
“High protein diets” are generally considered diets with protein accounting for ~30% of total daily energy intake. This comes out to roughly 0.8-1.2 grams per pound (depending on body weight, activity level, metabolism, etc.).
Two different studies have investigated the effects of “very high” protein intake on kidney function in resistance-trained individuals.
The first study has participants consume ~2.51–3.32 g/kg (1.14-1.5 g/lb) protein per day for an entire year and found no evidence of harmful effects concerning kidney function, liver function, or blood lipids.[3]
The second study had resistance-trained men consume upwards of 4.4g/kg (2g/lb) of protein per day for eight weeks and documented no detrimental effects to kidney function.[9]
You might also be interested to know that 4.4g/kg of protein per day is roughly FIVE times the RDA for protein intake.
Suffice it to say that if an individual is otherwise healthy (no history of kidney damage or disease) and exercises regularly, a high protein diet does not pose any inherent dangers or damage to kidneys.
Now, if someone has impaired kidney function or chronic kidney disease (CKD), it’s another story entirely, and protein intake should be monitored (under the guidance of a physician). The reason for this is that research notes that high-protein diets may worsen kidney function due to the difficulty CKD patients experience when trying to eliminate waste products of protein metabolism.
Myth #2: Protein Weakens Bones
The second most infamous protein myth to stop believing is that high protein diets weaken bones.
The myth stems from the misconception that consuming protein increases the acidity of the blood.
In order to prevent the body from becoming overly acidic (which could be toxic), it must remove calcium from bone to neutralize the acid.[11]
What’s not mentioned when discussing this protein myth is that the purported calcium-leaching from bone is transient, meaning it does not lead to long term decalcification of bone.[12]
In fact, longer studies give evidence that high protein diets not only support bone health, buy actually lead to improvements in several hormones (including IGF-1) that support bone health.[13]
Moreover, a comprehensive review of the literature in 2016 led by leading protein researcher Dr. Stu Phillips noted that:
“Despite persistent beliefs to the contrary, we can find no evidence-based link between higher protein diets and renal disease or adverse bone health.”[14]
A 2017 systematic review and meta-analysis conducted by The National Osteoporosis Foundation also concluded that high protein intakes do not weaken bones. Researchers did, however, document a positive trend towards higher protein intakes improving bone health.[15]
Yet another review, published in 2018 by the International Osteoporosis Foundation[16] noted that:
- Bone mineral density is positively correlated with dietary protein intakes (meaning higher protein intakes are linked to greater bone mineral density)
- Dairy products, which naturally combine protein with calcium, beneficially impact calciotropic hormones (hormones involved in the regulation of calcium in the blood and in bone), bone turnover markers and bone mineral density.
- No direct evidence was found between the acid load of higher protein intakes and compromised bone strength, the progression of osteoporosis, or bone fractures.
- Higher protein intakes lead to a slightly reduced risk of hip fracture, provided calcium intake is sufficient
Suffice it to say that this is another protein myth you need to stop believing.
Myth #3: Protein Cannot Cause Fat Gain
Earlier we mentioned that protein is very expensive from a metabolic standpoint to breakdown, meaning it takes a lot of energy to digest and absorb protein.
Now, when you consume more protein than your body needs, more energy is expended to convert it into storage products (carbs or fat) or burned for energy.
Based on this, many individuals think that protein cannot be stored as fat. There are also a couple of studies noting that individuals overconsuming protein in isolation do not gain body fat.[5,9]
Now, in theory, if you overeat your calorie needs, you will gain weight. This is basic thermodynamics.
Furthermore, certain amino acids (called glucogenic amino acids) can be converted into glucose and subsequently used for energy to again be converted and stored as fat.
Other amino acids are ketogenic amino acids and can be converted to a molecule called acetyl-CoA, which can be used for fatty acid synthesis or energy production.
Additionally, when you really crunch the calorie intakes of the subjects in the studies, you’ll find that they ate at maintenance or slightly more or less energy than they required. There was no gross over-consumption of total energy (from protein or any other macronutrient).
The truth is that protein is hard to over-eat (subjects in these studies were essentially force fed protein shakes to get their intakes up to the 3.4-4.4 g/kg range).[5,9]
Protein is highly satiating, meaning it keeps you full, and it’s highly thermogenic, meaning your body burns a lot of calories digesting it. In fact, roughly 30% of the energy our bodies get from protein is used to break it down.
Studies involving an energy surplus where subjects were over-consuming both protein and another macronutrient indicate it is possible to gain fat.
The takeaway here is that an excess intake of calories will lead to fat gain, regardless of the composition. Consuming a higher protein diet increases energy expenditure and satiety, both of which can help mitigate the amount of fat gained.
Myth #4: More Protein = More Muscle & Strength
At the beginning of this article, we mentioned that physically active individuals, especially those participating in resistance training and weight lifting, have increased demands for dietary protein.
This is to support the additional recovery and repair processes needed to accompany intense exercise as well as provide enough “raw materials” for the body to synthesize new muscle tissue.
However, there is a limit to everything, including the amount of protein needed to support muscle recovery and growth.
Yes, you do need to consume more protein in order to build muscle, but only to a certain point.
Above this threshold, excess protein will be converted to glucose and used for energy production, glycogen replenishment, energy storage, etc.
In other words, once you meet your personal dietary requirements for protein consuming substantially more won’t lead to exponentially greater muscle growth.
So, how much protein do you need to support muscle recovery and growth?
Current evidence suggests that resistance training individuals should consume between 1.6–2.2 g/kg/day of protein.[17]
Ideally, individuals would consume 0.40–0.55 g/kg dietary protein per meal and distributed those protein feedings evenly throughout the day (3–6 meals, depending on needs) including within 1–2 hours pre- and post-training.[17]
Best Protein Sources
Now that we’ve busted a few of the most popular (“infamous”) myths surrounding protein, let’s now discuss some of the best protein sources to include in your diet.
These sources of protein offer high bioavailability (meaning our bodies efficiently utilize them) as well as a complete spectrum of essential amino acids the body needs to repair and rebuild muscle tissue.
This list isn’t exhaustive by any means, but highlights some of our favorite protein sources to include in any muscle building or fat loss diet.
- Lean beef
- Chicken
- Turkey
- Eggs
- Whey Protein
- Bison
- Venison
- Greek Yogurt
- Cottage Cheese
- Shrimp
- Salmon
- Rainbow trout
- Steelhead trout
- Mahi Mahi
- Pork
1UP Whey Protein offers a wide variety of delicious flavors that are high in protein, easy to mix, and low in calories. They make for a delicious pre or post workout shake as well as a luxurious treat any other time of day.
References
- Hoffman JR, Falvo MJ. Protein - Which is Best?. J Sports Sci Med. 2004;3(3):118‐130. Published 2004 Sep 1.
- H. Jackson and O. J. Moore, “The effect of high protein diets on the remaining kidney of rats,” Journal of Clinical Investigation, vol. 5, no. 3, pp. 415–425, 1928.
- Jose Antonio, Anya Ellerbroek, Tobin Silver, et al., “A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males,” Journal of Nutrition and Metabolism, vol. 2016, Article ID 9104792, 5 pages, 2016. https://doi.org/10.1155/2016/9104792.
- Poortmans JR, Dellalieux O: Do regular high protein diets have potential health risks on kidney function in athletes? Int J Sport Nutr Exerc Metab 2000, 10:28-38.
- Antonio J, Peacock CA, Ellerbroek A, Fromhoff B, Silver T: The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals. J Int Soc Sports Nutr 2014, 11:19
- Devries MC, Sithamparapillai A, Brimble KS, Banfield L, Morton RW, Phillips SM. Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets: A Systematic Review and Meta-Analysis. J Nutr. 2018;148(11):1760-1775.
- F Martin, W., Armstrong, L., & Rodriguez, N. (2005). Dietary Protein Intake and Renal Function. Nutrition & Metabolism(Vol. 2). https://doi.org/10.1186/1743-7075-2-25
- Schwingshackl L, Hoffmann G. (2014) Comparison of High vs. Normal/Low Protein Diets on Renal Function in Subjects without Chronic Kidney Disease: A Systematic Review and Meta-Analysis. PLOS ONE 9(5): e97656. https://doi.org/10.1371/journal.pone.0097656
- J. Antonio, A. Ellerbroek, T. Silver et al., “A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women—a follow-up investigation,” Journal of the International Society of Sports Nutrition, vol. 12, no. 1, article 39, 2015.
- Friedman AN, Ogden LG, Foster GD, Klein S, Stein R, Miller B, Hill JO, Brill C, Bailer B, Rosenbaum DR, Wyatt HR: Comparative effects of low-carbohydrate high-protein versus low-fat diets on the kidney. Clin J Am Soc Nephrol 2012, 7:1103-1111.
- Barzel, U. S., & Massey, L. K. (1998). Excess dietary protein can adversely affect bone. The Journal of Nutrition, 128(6), 1051–1053. https://doi.org/10.1093/jn/128.6.1051
- Cao, J. J. (2017). High Dietary Protein Intake and Protein-Related Acid Load on Bone Health. Current Osteoporosis Reports, 15(6), 571–576. https://doi.org/10.1007/s11914-017-0408-6
- Dawson-Hughes, B., Harris, S. S., Rasmussen, H., Song, L., & Dallal, G. E. (2004). Effect of dietary protein supplements on calcium excretion in healthy older men and women. The Journal of Clinical Endocrinology and Metabolism, 89(3), 1169–1173. https://doi.org/10.1210/jc.2003-031466
- Phillips, S. M., Chevalier, S., & Leidy, H. J. (2016). Protein “requirements” beyond the RDA: Implications for optimizing health 1. Applied Physiology, Nutrition, and Metabolism, 41(999), 1-8. http://dx.doi.org/10.1139/apnm-2015-0550
- Shams-White, M. M., Chung, M., Du, M., Fu, Z., Insogna, K. L., Karlsen, M. C., … Weaver, C. M. (2017). Dietary protein and bone health: a systematic review and meta-analysis from the National Osteoporosis Foundation. The American Journal of Clinical Nutrition, 105(6), 1528–1543. https://doi.org/10.3945/ajcn.116.145110
- Rizzoli, R., Biver, E., Bonjour, JP. et al. Benefits and safety of dietary protein for bone health—an expert consensus paper endorsed by the European Society for Clinical and Economical Aspects of Osteopororosis, Osteoarthritis, and Musculoskeletal Diseases and by the International Osteoporosis Foundation. Osteoporos Int (2018) 29: 1933. https://doi.org/10.1007/s00198-018-4534-5
- Iraki J, Fitschen P, Espinar S, Helms E. Nutrition Recommendations for Bodybuilders in the Off-Season: A Narrative Review. Sports (Basel). 2019;7(7):154. Published 2019 Jun 26. doi:10.3390/sports7070154
