Everything You Need to Know About Protein Powder

Robin Berzin, MD
September 20, 2018

Protein is an essential part of a balanced diet, and depending on your diet, sometimes you may need a little extra in the form of a supplemental protein powder. But how do you choose a protein powder? We’re breaking it down.

Scan the shelf at the grocery store and there are literally hundreds of protein powders to choose from, so what’s the best protein powder for you? It largely depends on your goals and dietary needs and preferences—the same protein powder to help with muscle building might not be the best one if you’re just looking to make sure you’re getting adequate protein in your diet. After all, the healthiest protein is the one that meets your individual needs.

How to choose a protein powder

When you’re reading the labels of protein powders, there are a few things to keep in mind. First, ensure that the protein is third-party verified. That means an outside company has done quality control testing on the product to guarantee it contains everything it says it does and nothing it doesn’t. (Our Rebuild Protein Shakes go through this process, too). Two well-known third-party certifications are Informed-Choice and GMP.

For animal-based protein sources, look for organic, grass-fed, pasture-raised sources for meat and wild-caught, non-GMO for fish. For plant-based protein sources, look for organic, non-GMO sources. With both, avoid additional fillers, sweeteners, thickeners—the fewer ingredients the better.

Animal- vs. plant-based protein powder

A complete protein contains a balance of all nine essential amino acids in a way that’s ideal for your body. Animal proteins are complete protein sources. Some, but not all plant proteins are complete proteins, and even the ones that are complete often lack the ideal balance of amino acids that animal proteins have.

That means plant based protein powders are not as potent to start with, so to make up for it, smart plant-based protein powders (like our Rebuild Protein Shakes , which are now sugar-free!) have been optimized to mimic animal protein through the addition of specific amino acids.

Getting in more of your protein intake from plants is ideal, even if you’re not vegetarian or vegan. Research from Harvard recently found that higher intake of saturated fat from animals was linked to an 18 percent increased risk for heart disease. But by replacing one percent of those fats with the same number of calories from polyunsaturated fats, whole grains, or plant proteins, it decreased peoples’ risk by up to 8 percent.

Animal protein powders

Whey protein

Whey is a protein found in cow, goat, and sheep’s milk. High-quality, organic, grass-fed whey protein is the best protein powder source if you have no dietary restrictions because it’s highly bioavailable. That means it’s easy and quick for your body to absorb and use.

Unfortunately, dairy , and specifically dairy from cows, is a common digestive irritant and can also lead to low-grade inflammation in many people with no symptoms. Some people with dairy allergies or sensitivities find they can tolerate whey from goat or sheep’s milk with no problems. If you choose a protein powder made with whey, the key is to ensure it comes from high-quality sources.

Who it’s good for: People who tolerate dairy and want fast absorbing protein, such as after a workout to fuel muscles.

Casein protein

Casein is another protein found in milk, so if you’re avoiding dairy you’ll want to skip this. It digests much slower than whey, so unlike whey, it’s not ideal to consume after a workout. Instead, scientists have actually found that it’s slow digestion makes it good to use before bed. That might sounds odd, but being able to absorb protein while you sleep can be beneficial for some groups of people who need extra protein that they can’t get in during the day.

Who it’s good for: Athletes who want to maximize their recovery  and older individuals trying to counter muscle loss.

Collagen protein

Collagen makes up the majority of hair, skin, nails, organs, bones, ligaments, and connective tissue. Most collagen protein on the market comes from either cows or marine sources. Both have roughly the same nutritional value, so as long as they’re from high-quality sources, it comes down to preference.

Collagen will often be labeled as “collagen peptides” or “hydrolyzed collagen,” which indicates that some processing has taken place to make the collagen easily digested and absorbed.

Who it’s good for: Anyone with digestive issues looking for additional nutritional support, as collagen could help to repair the gut lining .

Egg protein

Most egg protein powder is made up of only the whites of eggs, so you do lose out on some the beneficial vitamins and minerals found in the yolk. If muscle building is one of your goals, you’re better off consuming the whole egg, yolk included, recent research in the American Journal of Clinical Nutrition has found.

Who it’s good for: Anyone without an allergy to eggs and who looking for a protein powder that is low in fat and carbohydrates

Plant-based protein powders

Pea protein

Pea protein is typically made from yellow peas and has been gaining traction as a vegan protein source. Unlike some other plant proteins, peas are a complete protein, meaning they have all nine essential amino acids needed for necessary processes within the body. Peas are also high in fiber , vitamin K, A, C, B vitamins, and manganese. That’s why it’s the main ingredient in both our Vanilla and Chocolate Sugar-Free Rebuild Protein Shakes .

Research in the Journal of the International Society of Sports Nutrition found that pea and whey proteins had about the same effect on muscle growth.

Who it’s good for: Most people can tolerate and benefit from pea protein, and it’s a great option for plant-based athletes.

Hemp protein

Hemp contains all the essential amino acids, but it’s less bioavailable than many other protein sources, so your body can’t absorb it as well. It’s also lower in protein content than other protein sources, but it has more fiber and fatty acids.

Who it’s good for: If you’re vegan or vegetarian and avoiding grains or are trying a plant-based Paleo diet, hemp protein powder is another option you can try.

Soy protein

Soy protein powder was a favorite among vegetarians for a long time because soy contains all nine essential amino acids and is relatively inexpensive, but the problem with many soy products, including soy protein powder, is that they are heavily processed. This can strip soy of its phytochemicals that balance out its potentially dangerous estrogen-like compounds . And since most soy in the U.S. is made from GMO sources, it’s generally not the best type of protein powder available.

Who it’s good for: Vegans or vegetarians who need another protein source in their diet should talk to their doctor before consuming soy protein powder.

Brown rice protein

Brown rice protein is another complete protein source and is also rich in vitamin C and iron. Research in Nutrition Journal found that when people consumed either whey or rice protein after their resistance training workouts over the course of eight weeks, both groups decreased fat mass, increased lean body mass and muscle, and saw equivalent strength and power gains.

Who it’s good for: Anyone not on a grain-free diet can usually tolerate brown rice protein well. Those will blood sugar issues may also find it helps them to balance blood sugar .

Blended protein powders

Many brands (Parsley Health included) will combine different plant sources in their protein powder to get the ideal amino acid profile, making the final product nutritionally closer to animal protein.

Robin Berzin, MD

Dr. Robin Berzin is the Founder and CEO of Parsley Health, America's leading holistic medical practice designed to help women overcome chronic conditions. She founded Parsley to address the rising tide of chronic disease in America through personalized holistic medicine that puts food, lifestyle, and proactive diagnostic testing on the prescription pad next to medications. Since founding Parsley in 2016, Dr. Berzin has seen 80% of patients improve or resolve their chronic conditions within their first year of care, demonstrating the life-changing value of making modern holistic medicine accessible to everyone, anywhere. Parsley is available online nationwide.

Dr. Berzin attended medical school at Columbia University and trained in Internal Medicine at Mount Sinai Hospital in New York City. Her book, Prescription for Happiness: How to Eat, Move, and Supplement for Peak Mental Health, was published by Simon Element in January 2022.

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