When you were little, your parents may have tried to get you to eat your vegetables by telling you that you need them to grow up big and strong. While certainly true (though not always the most persuasive argument to a young mind), hearty greens pale in comparison to the power of dietary protein for strength, muscle, and, in some cases, even health.
Proteins are found within — and around — each cell of your body, taking part in every bodily process from digestion and tissue repair to immune and brain function.
Though protein is essential for the bodybuilder avidly pursuing muscle growth or the strength athlete grinding away for a new personal record in the weight room, it provides a number of other health benefits as well. Fortunately, you can obtain dietary protein from a wide variety of both animal and plant-based foods to support your health and longevity.
Benefits of Protein
- Grows and Repairs Tissue
- Converts Food Into Energy
- Facilitates Cellular Communication
- Bolsters Your Immune System
- Enables Hypertrophy
- Supports Bone and Brain Health
- Regulates Digestive Health
Editor’s Note: The content on BarBend is meant to be informative in nature, but it should not be taken as medical advice. When starting a new training regimen and/or diet, it is always a good idea to consult with a trusted medical professional. We are not a medical resource. The opinions and articles on this site are not intended for use as diagnosis, prevention, and/or treatment of health problems. They are not substitutes for consulting a qualified medical professional.
Types of Protein
Protein is one of the three primary macronutrients (the other two being dietary fat and carbohydrate). It’s a composite of different amino acids bound together and then folded into “functional” shapes, each of which is suited for a different task in your body.
There are many different types of protein, each with a unique set and arrangement of amino acids — but they all have their own little important jobs to carry out behind the curtain.
Animal vs. Plant Proteins
Some amino acids are considered to be essential because they can’t be made in the body, so they have to be eaten in adequate amounts as part of your diet. When a dietary protein source is described as “complete” or “high-quality,” that generally means it provides all of the essential amino acids in adequate amounts. (1)
Animal proteins like meat and dairy are considered complete proteins. Most plant proteins are considered to be incomplete because they either wholly lack or have very low amounts of one (or more) of the essential amino acids. (1)
That said, a meat and dairy-free diet can still provide all of the essential amino acids in adequate amounts as long as it includes a variety of protein sources like beans, tofu, and whole grains (or if you choose to supplement your diet with, well, a supplement).
The amino acid profiles of many protein sources are often are complementary, which means that certain foods will have more of an amino acid that others might lack. (2)
Whole Foods vs. Meal Replacements
It might seem like protein shakes are necessary for athletes and fitness enthusiasts, but in reality, they’re a convenience, not a requirement. Protein powders are quick, easy, and portable, so they’re helpful if you’re on the go or have a very high protein intake requirement.
Whole foods can promote post-workout muscle protein synthesis and glycogen replenishment just as effectively, and usually at a lower cost per serving.
If it’s difficult to meet your protein requirements with whole food sources, one of the easiest solutions is to add a protein shake, (3) but you probably shouldn’t make shakes your primary source of protein long-term.
Every tissue and organ in the body contains proteins. Your intestines, bones, tendons, ligaments, and skin contain different types of a protein called collagen, which adds flexibility and elasticity.
Without collagen, your bones would be dangerously brittle and your joints would be extremely unstable. Your muscle cells also contain specialized contractile proteins called myosin and actin, which bind temporarily and bend to produce a muscle contraction. (4)
Your skin, hair, and nails contain keratin, a protein that strengthens your hair and nails while helping to create a waterproof barrier on the surface of your skin. Some of the proteins in your cells are used for storage, like ferritin, which stores iron in your intestinal cells. (4)
Protein can also take the form of enzymes, which catalyze chemical reactions. Enzymes are used to digest food in the intestines and can also regulate metabolic processes. For example, the enzyme lactase is used to break down lactose (a sugar found in most dairy processes.)
A cell receptor made of protein will allow the sugars to enter the cell where they can be used to make adenosine triphosphate (ATP) via a metabolic pathway catalyzed by enzymes (4) — ATP powers a large swath of intense athletic activities.
Cells communicate with each other in a number of ways that rely on proteins. In the nervous system, some neurotransmitters are made of proteins. Some hormones are made of proteins, too.
These types of neurotransmitters and hormones bind to specific receptors (also made of protein) on the surface of a cell to initiate or stop a process within that cell.
For example, when growth hormone binds to its receptor on a muscle cell, it initiates a process (catalyzed by enzymes) that activates muscle growth pathways. (4)
Your immune system uses a few types of proteins for cell-to-cell communication and fighting off infections. Antibodies are used to identify intruders as well as the body’s own cells, which normally prevents the immune system from attacking cells of the body.(4)
When an immune reaction is required, hormones called cytokines regulate the inflammatory process. Immune cells also produce proteins that can destroy infectious microbes and clean up damaged areas. (4)
If a physique change is your goal, protein is a real MVP for improving both size and strength. The amino acid leucine, specifically, is a potent stimulator of muscle protein synthesis, making it an important part of your post-workout meal. (5)
Though it has only a modest (if any) effect on your hunger levels, eating enough protein can prevent some of the muscle loss that takes place when you’re in a caloric deficit.
However, it can’t overcome the catabolic effects of a very low calorie diet, so it’s important to maintain a moderate deficit while you’re trying to shed some fat. (6) On the other hand, if you’re in a caloric excess to add some muscle mass, your body needs those spare amino acids from your dietary protein sources. (5)
Despite the pervasive myth that animal proteins may cause bones to lose density, adequate protein intake is associated with higher bone mineral density, especially in the elderly. (7)
This is an important factor that protects against fractures and frailty, which can improve longevity and increase life expectancy. A lower-fat, higher-protein and carb diet is also associated with better cognitive function in older individuals. (8)
Collagen is a component of the intestinal wall, and intestinal cells require plenty of the amino acid glutamine. That being said, there’s no direct evidence that supplementing with either one will improve your performance, immune system, or body composition. (9)
It might also bring intestinal permeability (often called “leaky gut”) back to a normal level in people with IBS-D, which is associated with abnormally high permeability. Collagen, on the other hand, isn’t supported by any human trials yet.
How Much Protein Do You Need?
One of the biggest pain points of the scientific community is its frustrating but necessary stance of “it depends” on most aspects of health. Fortunately, when it comes to determining protein intake (at least broadly), the literature is as close to crystal-clear as it gets.
Bodies like the World Health Organization or Food & Drug Administration tend to advise that most people consume a surprisingly low amount of protein on a daily basis — think in the ballpark of .3 to .5 grams per pound of bodyweight, per day. (12)
However, if you like to hit the gym on a regular basis or are a competitive athlete, your protein needs shoot up dramatically. This is because of protein’s vital supportive function for muscle growth and repair, among other factors.
Take our protein intake calculator for a spin and see for yourself:
Protein Intake Calculator
In the broadest of strokes, you should aim to consume about one gram of protein per pound of body weight, per day, if you exercise regularly (particularly if you lift weights). (13) You may even need a bit more than that if you’re an advanced trainee or are in a cutting phase.
The Power Is in the Protein
Protein is a key ingredient for good health, and it goes way beyond helping you build muscle. It’s vital for every process in the body! Whether you’re an omnivore or a vegan, it’s best to include a variety of protein sources to meet your goals.
Protein powders aren’t a necessary addition to your diet, but they are a portable, convenient option then you’re on the go. By meeting your protein needs each day, you’re supporting your physique goals, longevity, and gut barrier. When it comes to protein, you really can’t go wrong.
1. Spano, M., Kruskall, L., & Thomas, D. T. (2017). Nutrition for Sport, Fitness and Health. Human Kinetics.
2. Hevia-Larraín, V., Gualano, B., Longobardi, I., Gil, S., Fernandes, A. L., Costa, L., Pereira, R., Artioli, G. G., Phillips, S. M., & Roschel, H. (2021). High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores. Sports medicine (Auckland, N.Z.), 51(6), 1317–1330.
3. Vliet, S. V., Beals, J. W., Martinez, I. G., Skinner, S. K., & Burd, N. A. (2018). Achieving Optimal Post-Exercise Muscle Protein Remodeling in Physically Active Adults through Whole Food Consumption. Nutrients, 10(2), 224.
4. Martini, F. H., Nath, J. L., & Bartholomew, E. F. (2017). Fundamentals of anatomy & physiology, books a la carte edition (11th ed.). Pearson.
5. Antonio, J., Candow, D. G., Forbes, S. C., Ormsbee, M. J., Saracino, P. G., & Roberts, J. (2020). Effects of Dietary Protein on Body Composition in Exercising Individuals. Nutrients, 12(6), 1890.
6. Calbet, J., Ponce-González, J. G., Calle-Herrero, J., Perez-Suarez, I., Martin-Rincon, M., Santana, A., Morales-Alamo, D., & Holmberg, H. C. (2017). Exercise Preserves Lean Mass and Performance during Severe Energy Deficit: The Role of Exercise Volume and Dietary Protein Content. Frontiers in physiology, 8, 483.
7. Ashley A Weaver, PhD, Janet A Tooze, PhD, Jane A Cauley, PhD, Douglas C Bauer, MD, Frances A Tylavsky, PhD, Stephen B Kritchevsky, PhD, Denise K Houston, PhD, Effect of Dietary Protein Intake on Bone Mineral Density and Fracture Incidence in Older Adults in the Health, Aging, and Body Composition Study, The Journals of Gerontology: Series A, Volume 76, Issue 12, December 2021, Pages 2213–2222
8. Coelho-Júnior, H. J., Calvani, R., Landi, F., Picca, A., & Marzetti, E. (2021). Protein Intake and Cognitive Function in Older Adults: A Systematic Review and Meta-Analysis. Nutrition and metabolic insights, 14, 11786388211022373.
9. Ramezani Ahmadi, A., Rayyani, E., Bahreini, M., & Mansoori, A. (2019). The effect of glutamine supplementation on athletic performance, body composition, and immune function: A systematic review and a meta-analysis of clinical trials. Clinical nutrition (Edinburgh, Scotland), 38(3), 1076–1091.
10. Bertrand, J., Ghouzali, I., Guérin, C., Bôle-Feysot, C., Gouteux, M., Déchelotte, P., Ducrotté, P., & Coëffier, M. (2016). Glutamine Restores Tight Junction Protein Claudin-1 Expression in Colonic Mucosa of Patients With Diarrhea-Predominant Irritable Bowel Syndrome. JPEN. Journal of parenteral and enteral nutrition, 40(8), 1170–1176.
11. Zhou, Q., Verne, M. L., Fields, J. Z., Lefante, J. J., Basra, S., Salameh, H., & Verne, G. N. (2019). Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut, 68(6), 996–1002.
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