What’s the big deal about protein? It builds and repairs muscle tissue. It also supports immune function and satisfies your appetite, so you feel full between meals. Studies also show it’s the most satiating of the three macronutrients, protein, carbohydrates, and fat, meaning it keeps you satiated longer than eating a similar amount of carbohydrates or fat.
With so much focus on protein, it’s no wonder there are myths and misconceptions floating around about how much you need and what foods you should get it from. Let’s separate protein fact from fiction.
Myth #1: You Need Lots of Protein
Fitness magazines often say you need to consume at least 1 gram of protein for every pound you weigh to support muscle growth and prevent muscle breakdown. But is all that protein necessary, or is this just another myth the bodybuilders perpetuate?
Reality: According to research, the average person only needs 0.36-0.45 grams of protein per pound of body weight per day. Strength athletes and hardcore exercisers need a little more – 0.54-0.68 grams per pound – but nowhere near the mythical 1 gram per pound each day. Where did that number come from?
Some sources believe the 1-gram rule is an effort by protein powder companies to sell more products. Others say it stems from a misunderstanding of the role protein plays in muscle repair and how much is necessary to do the job. Regardless of the origins, it persists, especially in bodybuilding circles.
Not everyone who works out needs a full gram of protein per pound of body weight daily. However, you need more protein, sometimes up to a gram per pound of body weight, if you do heavy weight training or high-intensity exercise. So, it’s important to adjust your protein intake to your goals and workouts. But if you’re inactive or do light workouts, you don’t need a full gram per pound of body weight.
Myth #2: Plant Proteins Are Incomplete
The confusion about plant protein being incomplete stems from an outdated hypothesis about protein combining. In the 1970s, researchers theorized that you need to combine certain plant foods in the same meal to get all the essential aminos. So, for example, you’d have to mix beans with rice and eat them in the same meal, as beans contain the amino acids that rice lacks and vice versa.
Reality: The human body can utilize amino acids from a varied plant-based diet over the course of a day. It doesn’t require food combining to get the benefits of plant-based protein. If you eat a variety of plant proteins like beans, lentils, tempeh, and tofu spread over a day, you will get all the essential amino acids your muscles need to repair and grow.
Myth #3: Soy Reduces Testosterone in Males
In the 1990s and early 2000s, a few small studies found that soy supplements containing high doses of isolated isoflavones reduced testosterone levels in men. These early studies fueled speculation that the phytoestrogens in soy mimic estrogen in the human body and could be harmful to males by affecting testosterone.
Reality: It seems those early small studies led to premature conclusions. The phytoestrogens in soy do not appear to significantly impact hormones in men who eat moderate quantities of soy foods as part of a balanced diet. There is no strong evidence that consuming soy foods leads to decreased testosterone levels in men. Soy contains phytoestrogens, but multiple studies show these do not significantly affect testosterone in the amount most people eat.
Therefore, most men can still enjoy edamame and tempeh guilt-free. However, they shouldn’t overdo supplements containing concentrated soy isoflavones, as the effects of concentrated sources on hormones are less clear. Moderation is key when it comes to soy as well as other foods.
Myth #4: You Need Protein Supplements
People think they need fancy protein powders and supplements to maximize strength training gains. Manufacturers of protein powders and shakes have hammered this message into people’s heads.
Reality: Protein supplements like powders and bars are unnecessary for most people who meet their protein needs through whole food sources. Foods like meat, dairy, eggs, legumes, and soy products should be the bulk of the average person’s protein intake.
While supplements can be useful for athletes and those who struggle to eat enough high-protein whole foods, they’re not a requirement for building muscle or getting stronger. Plus, they’re highly processed. Even worse, independent testing shows some contain heavy metals.
Myth #5: High Protein Diets Cause Kidney Damage
The idea that eating a lot of protein might strain or damage the kidneys was popular years ago. It makes logical sense on the surface. Since your kidneys are responsible for processing protein byproducts, you might think eating more protein would strain your kidneys.
Reality: There is no evidence that high protein diets place excessive stress on healthy kidneys or cause kidney problems. These issues only occur in those with pre-existing kidney disease or dysfunction. Consuming protein within the recommended daily ranges does not negatively impact kidney function in healthy people.
However, if you already have compromised kidney function, due to diabetes, hypertension, or other issues, your doctor may still recommend that you moderate your protein intake.
Keep These Myths about Protein in Mind When Planning Your Diet
Protein needs vary based on your goals. If you strength train intensely, aim for 0.54-0.68 grams of protein per pound of body weight from high quality whole food sources like meat, dairy, eggs, beans, and soy foods. Supplements can help fill gaps for some athletes but aren’t unnecessary for most. And plant proteins can meet all your amino acid needs over the course of a day. Hopefully, this clears up some of the most common myths about protein.
References:
- Reed KE, Camargo J, Hamilton-Reeves J, Kurzer M, Messina M. Neither soy nor isoflavone intake affects male reproductive hormones: An expanded and updated meta-analysis of clinical studies. Reprod Toxicol. 2021 Mar;100:60-67. doi: 10.1016/j.reprotox.2020.12.019. Epub 2020 Dec 28. PMID: 33383165.
- Ko GJ, Rhee CM, Kalantar-Zadeh K, Joshi S. The Effects of High-Protein Diets on Kidney Health and Longevity. J Am Soc Nephrol. 2020 Aug;31(8):1667-1679. doi: 10.1681/ASN.2020010028. Epub 2020 Jul 15. PMID: 32669325; PMCID: PMC7460905.
- Messina, Mark, Alison Duncan, Virginia Messina, Heidi Lynch, Jessica Kiel, and John W Erdman. “The Health Effects of Soy: A Reference Guide for Health Professionals.” Frontiers in Nutrition 9 (August 11, 2022). doi.org/10.3389/fnut.2022.970364.
- US), Medicine. “Effects of Protein Intake on Renal Function and on the Development of Renal Disease.” Nih.gov. National Academies Press (US), 2024. https://www.ncbi.nlm.nih.gov/books/NBK224634/.
- “Arsenic, Lead Found in Popular Protein Supplements.” 12 Mar. 2018, .consumerreports.org/dietary-supplements/heavy-metals-in-protein-supplements/.
- Abou-Samra R, Keersmaekers L, Brienza D, Mukherjee R, Macé K. Effect of different protein sources on satiation and short-term satiety when consumed as a starter. Nutr J. 2011 Dec 23;10:139. doi: 10.1186/1475-2891-10-139. PMID: 22196620; PMCID: PMC3295702.
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