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Whey Protein vs Plant Protein: What's the Difference?

Whey Protein vs Plant Protein: What's the Difference?


If you do a quick internet search for “protein powder,” you’ll quickly discover there are tons of different types of protein powder on the market. There’s whey protein powder, casein protein powder, egg white protein powder, plant-based protein powders — the list goes on and on.


So what’s the difference between these types of protein powders? How do you know which one is right for you?


Below, we’ll dissect the differences between whey protein, which is a dairy-based protein powder and arguably the most popular type of protein powder available, and plant-based protein powders.  

What is whey protein?

As mentioned above, whey protein powder comes from an animal protein source and is one of the most popular types of protein powder out there. Derived from milk during cheesemaking, whey is the liquid portion of milk that separates during this process. If you have ever opened a container of yogurt and found liquid at the top, then you can picture what whey is. After going through the process of filtering and drying, that liquid becomes the whey protein powder. 


Whey protein is a complete protein, meaning it contains all nine of the essential amino acids. While some amino acids are produced naturally by your body, others can only be obtained through food. These amino acids are called essential amino acids. Whey protein is especially high in branched-chain amino acids (BCAAs) like leucine, which is the amino acid most effective for muscle growth, recovery and repair because it activates a certain pathway in the body that stimulates muscle protein synthesis. BCAAs help prevent or slow muscle breakdown during exercise and are key for muscle building. According to a 2017 study published in the journal Nutrients, whey protein supplementation can enhance whole body protein metabolism and performance recovery after resistance exercise.


Whey protein can be found in different forms: concentrate, isolate and hydrolysate. Whey concentrate contains roughly 70-80% protein as well as lactose. Due to varying processing methods, there are several nutritional differences between whey isolate and concentrate. Using steps to reduce whey’s fat and carbohydrate content, whey isolate powder ends up containing 90% or more protein. By having a higher protein content, whey isolate has less carbs, lactose and fat — and that’s generally a good thing; however, whey protein isolate might not be ideal if you’re especially sensitive to lactose or have lactose intolerance. Just because whey isolate has less lactose content doesn’t necessarily mean it’s lactose-free. (That said, some whey protein powders with whey isolate, like Gainful, are so finely filtered, they are considered virtually lactose-free.)

Hydrolysate whey is known for being absorbed faster than other forms of whey, though whey in general is a fast-absorbing protein source. It’s fast-absorbing nature is one of the reasons why whey is so popular among athletes who want a good dose of protein before, after or during a workout.


Whey isn’t the only type of animal milk-based protein powder. There are also proteins like casein protein and egg white protein. Casein protein is fairly similar to whey protein. Both are made from milk particles and typically come in a fine, powdered form; however, casein is a slow-digesting protein. Casein moves through the digestive system more slowly than whey, as noted in a 2018 study published in the Journal of the International Society of Sports Nutrition. Whey’s higher leucine content is what allows it to be absorbed much faster. Eggs can also be a valuable source of high-quality, complete protein, as noted in an article titled “Egg Protein as a Source of Power, Strength, and Energy” published in the journal Nutrition Today. That said, whole eggs themselves also have more cholesterol, fat content because of their animal-derived origins. Egg white protein powder however, is cholesterol-free because it does not utilize the yoke which is the source of the fat and cholesterol.  

Of the animal milk proteins, whey is undoubtedly the most popular.

What is plant-based protein?

Just like there are a number of animal--based proteins, there are a handful of plant-based protein options. Four of the most popular plant-based proteins are pea protein, soy protein, brown rice protein and hemp protein. 


Pea protein is the protein extracted from yellow split peas. The protein is isolated from the ground yellow peas, which forms a protein powder. Pea protein is a high-quality protein and a great source of iron, naturally vegan, hypoallergenic and one of the more easily digested plant-based proteins. Pea protein does not contain any of the top food allergens such as peanuts, tree nuts, eggs, fish, shellfish, cow’s milk, wheat and soy, which makes it a great option for people with dietary restrictions or food allergies. Pea protein contains all nine essential amino acids; however, despite containing all nine essential amino acids, it is not considered a complete protein. That’s because it’s an inadequate source of methionine and cysteine. A complete protein provides at least 25 mg/g of methionine and cysteine, and pea protein only delivers around 11 mg/g. If you choose to supplement with pea protein, you’ll need to get proper amounts of methionine and cysteine from other protein sources, such as brown rice protein.


Brown rice protein is a protein supplement made from brown rice. To convert into powder form, the brown rice is treated with select enzymes that cause the protein and carbohydrates that make up the rice to separate and isolate the protein. According to a 2014 article titled “Amino Acid Composition of an Organic Brown Rice Protein Concentrate and Isolate Compared to Soy and Whey Concentrates and Isolates” published in the peer-reviewed Foods journal, brown rice contains 37% of the total protein as essential amino acids and 18% as BCAAs, making it an optional source of protein and nutrient density. Like pea protein, brown rice protein is also not considered a complete protein. That’s because it lacks lysine. Therefore, brown rice protein should still be combined with another lysine-containing protein, such as collagen.


Soy protein is made from defatted soybean flakes that have been washed in either alcohol or water to remove extras like sugars and dietary fiber. According to a 2016 study titled “Soy and Health Update: Evaluation of the Clinical and Epidemiologic Literature” published in the journal Nutrients, the protein from soybeans is a lot different from other legumes, as soy protein is higher in quality than other legume proteins. The soybean is also a good source of both essential fatty acids. Due to its versatility, soy protein catapulted in popularity in Western diets over the past few decades; however, soy protein has proven to be controversial in recent years, as it contains phytates, also known as antinutrients. Phytates reduce the availability of iron and zinc in soy protein. Additionally, many people are wary of soy protein because of its phytoestrogen content. Phytoestrogens are chemical compounds that occur naturally in plants and have estrogen-like properties that can disrupt natural hormone levels in the body. Phytates can be found in grains, seeds, nuts and some vegetables in addition to soy. Phytates can reduce absorption of some minerals; however, they also have some health benefits. Soaking, cooking and processing reduces phytates. Soy protein powder is made from soybeans that are rinsed in alcohol and water which does remove a good portion of the phytoestrogen content, but many men still worry that soy protein could decrease their testosterone levels. That’s why many athletes prefer to keep their protein powders soy-free. 


(That said, it’s important to note that research does not support this claim. While soy protein phytoestrogens park in the body in the same place as the hormone estrogen, they are not the hormone and are thousands of times weaker than actual estrogen. Phytoestrogen content in soy protein isolate and concentrate is variable and can actually be quite low. Soy protein, though, is a highly pesticide-laden crop and the only way to ensure less pesticide residue is to consume non-GMO soy or organic certified soy.) 


There’s also hemp protein, which is made by removing the oil from shelled hemp seeds. The remaining solid is then powdered to make hemp protein powder. Hemp protein powder has a moderate protein level and a notable amount of fiber. Even though the oil is removed, hemp protein powder actually still retains a healthy ratio of the Omega oils that hemp is known for. 


While there are numerous plant protein powders on the market and each offers its own set of benefits, pea protein and brown rice protein tend to reign as the most popular plant-based proteins. 

Whey protein vs. plant protein: What’s the best protein for building muscle? 

Studies agree that plant-sourced proteins offer numerous environmental and health benefits, but when it comes to building muscle, plant-based proteins have less of an anabolic effect than animal proteins due to their lower digestibility, lower essential amino acid content (especially leucine), and deficiency in other essential amino acids, including sulfur amino acids or lysine. 

According to a 2019 study titled “The Role of the Anabolic Properties of Plant- versus Animal-Based Protein Sources in Supporting Muscle Mass Maintenance: A Critical Review” published in the journal Nutrients, plant amino acids are directed toward oxidation rather than used for muscle protein synthesis. A different study titled “Plant Proteins: Assessing Their Nutritional Quality and Effects on Health and Physical Function” also published in Nutrients in 2020 noted that the nutritional quality of plant proteins may be inferior in several respects relative to animal proteins — including muscle protein synthesis. 


That isn’t to say plant protein won’t still help you achieve your muscle-building goals, however: A 2015 study titled “Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein” published in the Journal of the International Society of Sports Nutrition looked at pea protein’s effects on bodybuilding. The study had male participants between the ages of 18 and 35 follow the same 12-week upper-body lifting program. One group supplemented with 25 grams of pea protein twice a day, and another took the exact same amount of whey protein. Each 25 grams of protein from pea protein delivered around two grams of leucine, compared to 2.65 grams for whey, but both fell right in the middle of the optimal leucine range. Researchers recorded their biceps’ muscle thickness at the beginning and end of the study, and at the end of the 12 weeks, both groups showed identical increases in muscle thickness. Both pea protein and whey protein types also showed greater results than the placebo. 


So as long as you’re getting sufficient leucine from your plant protein supplement, plant protein can still help you build muscle in a comparable way to whey, though whey may be slightly a better fit if your goals center on major gains. 


What’s the best type of protein for weight loss?

Protein powder has a reputation for helping bodybuilders bulk up — but what if your goal is weight loss? Should you supplement with whey protein, or is plant protein your best bet?


A 2013 study titled “The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance” published in Nutrition Journal studies both whey protein and rice protein’s effects on the body. The athletes who used rice protein after doing resistance exercises over the course of eight weeks had an increase in lean body mass and decrease in fat-mass. Those who used whey protein also had very similar results. When researchers instructed the athletes to use the proteins in larger or maximum doses, the effects of the two protein types were once again comparable, if not completely equal. This leads researchers to believe that both whey protein and plant protein supplementation are great for fat loss and can help you achieve your weight loss goals. 

Find your perfect protein powder with a personalized formula

It can be a bit confusing to navigate the whey vs. plant protein battle and figure out which type of protein powder is best for you. The team at Gainful realizes it’s tough finding a “perfect” protein that aligns with your lifestyle, diet and overall goals (and still tastes delicious) so that’s why they’re here to help.


Gainful is a subscription protein powder company that delivers you a personalized blend made from high-quality, natural ingredients. Your customized protein supplement is created based on your body type, dietary needs, food allergies, activity level, wellness goals and personal preference. You just take a quiz to find your personalized blend and Gainful takes care of the rest. Each month, you’ll receive unflavored protein and your choice of single-serving Flavor Boost sticks (which are made from natural sources of sweetness, like stevia and monk fruit extract, and are free from artificial sweeteners) to create your perfect mix. You can use your blend in protein shakes, smoothies, meal replacement bars or add it to foods that need a nutritional boost. Gainful offers everything from whey protein to vegan protein powders to protein powders low in calories, so there truly is something for everyone, whether you’re building muscle, beginning a weight loss journey or just simply want to add more protein to your diet. 


No matter where you fall in the whey vs. plant protein debate, there are countless health benefits of integrating a personalized protein powder into your lifestyle. 

These statements have not been evaluated by the Food and Drug Administration.
This product is not intended to diagnose, treat, cure or prevent any disease.

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