Whey Protein Vs. Plant Protein

Vegan athletes. 

They’re everywhere, and they’re kicking ass.

But are they really?

There’s Venus Williams (tennis), Colin Kaepernick (football), David Haye (boxing), Jermain Defoe (soccer), and Arnold Schwarzenegger.

These athletes have infiltrated the ultra-endurance world, too.

For example, Rich Roll completed five ironman-distance triathlons is less than a week and was a top finisher of the Ultraman World Championships in 2008 and 2009.

More plant-powered endurance athletes include Scott Jurek (ultramarathoner), Bart Yasso (ultrarunner), and Brendan Brazier (triathlete).  

To be clear, I think these athletes would kick ass regardless of what diet they follow (although some might disagree with me).

However, what is clear is that these top athletes are performing extremely well on a plant-based diet.

Maybe that means you can, too.

Benefits of a plant-based, vegan or vegetarian diet

benefits of plant based diet

A vegan or vegetarian diet, or even just a diet low in animal products, has a few clear benefits.

Lessens carbon footprint

This is perhaps the most compelling reason for adopting a plant-heavy diet. Climate scientists agree: animal products are a major contributor to global greenhouse gas emissions.

Eating less meat and animal products can reduce your carbon footprint. (IPCC)

Has moral or ethical implications

Many vegans and vegetarians choose not to eat meat for moral or ethical reasons. One clear way to reduce factory farming is to eat less meat. It really is that simple.

Another option is to look for locally raised, free-range meat products. And of course, the closer to you your meat is raised, the lower the carbon footprint of that meat.

Promotes high carbohydrate consumption

Endurance athletes need carbs, and lots of them.

A plant-based diet promotes high carbohydrate consumption, making it an attractive diet for endurance athletes (and for the same reason, a less attractive diet for bodybuilders). 

Lower BMI, blood pressure, cholesterol, and risk of type II diabetes

A meta-analysis of observational studies and clinical trials showed a correlation between a plant-based diet and a lower BMI, risk of heart disease, and risk of type II diabetes. (Turner-McGrievy)


When it comes to the effects of a plant-based diet on BMI, blood pressure, cholesterol, and risk of diabetes, there are a few things to consider.

Much of the research that shows a plant-based diet reduces the following is observational.

That means that scientists simply studied a large population of people on plant-based diets and compared their health to the rest of the population.

While observational studies do offer important information, they can’t reduce certain variables.

For example, perhaps vegetarians are more likely to exercise than the general population, perhaps they are younger than the average population, or maybe they simply eat less calories.

It’s important to realize these folks are on a plant-based diet, meaning their calories come mostly from plants—not pizza and beer, which is still vegetarian, but isn’t necessarily going to help you improve your health.

Most of the research done on plant-based diets and overall health has been on obese populations, not in healthy athletes.

While there are benefits to a vegan or vegetarian diet (the environmental and moral arguments may be particularly compelling), there are some obvious issues.

Aside from the restrictiveness of a plant-based diet, there are logistical complications with regard to protein consumption.

The first thing most athletes who want to know more about a plant-based diet ask is:

How can I get enough protein on a plant-based diet? 

Below is the Ultimate Guide to Plant-Based Proteins.

How much protein do I need?

protein requirements for athletes

To answer the question above, you need to know how much protein your body needs to perform optimally.

Research shows that athletes need more protein than sedentary people.

Protein is necessary for building and maintaining muscles and for optimal recovery. And by the way, it isn’t bad for your kidneys, either. To learn about calculating protein requirements, especially for older athletes, go here.  

And the less animal products you eat, the more thought you need to put into your daily protein requirements. (Hoffman)

For athletes, the widely agreed upon protein requirements is between 1.2–2.0 g/kg body weight. At this amount, athletes can optimally recover from training and maintain muscle mass.

According to Examine, the average amount of protein required to maximize lean mass is about 1.6 g/kg, and some people need upwards of 2.2 g/kg.

Actually, many sports scientists suggest erring on the high side.

Let’s look at what that means for a 140 lb (63.5 kg) athlete trying to reach 1.6 g of protein per kg.

63.5 kg * 1.6 g = 101.6 g

This athlete may choose to consume about 100 grams of protein a day to maintain lean muscle mass.

According to data from Johns Hopkins Medicine, that’s the equivalent of:

  • 14 oz of animal meat, including beef, chicken, turkey, pork, lamb, or fish
  • 8 cups of yogurt
  • 6 cups of edamame
  • 33 oz of tofu
  • 5.5 cups of lentils
  • 25 oz of nuts
  • 28 tablespoons of peanut butter

As you can see, it’s hard work getting enough protein for top performanceeven for athletes who eat meat. 

For those on a plant-based diet, it can feel like a constant battle. Especially for those trying to gain muscle.

The most obvious solution to this problem is supplementing with protein powder.

Understanding dietary protein

What is whey protein?

what's a good whey protein powder

Whey protein is the liquid byproduct of cheese production. Eventually, someone realized that whey is packed with protein and really, really cheap.

It quickly became the go-to supplement for weightlifters and bodybuilders.

Whey is effective, inexpensive, and has undergone loads of clinical research and deemed safe.

What is plant protein?

Plant protein, or plant-based protein, is protein derived from plants.

A plant-based diet is simply the phrase most researchers use to describe a vegan diet, meaning a diet that excludes animal products.

If you are a vegan, or a vegetarian who doesn’t eat daily animal protein, you may consider paying attention to amino acid profile of the foods you eat.

That’s because protein derived from plants is different than protein derived from animals.

Let’s back up.

Amino acid basics

There are 20 amino acids your body uses to build proteins.

Eleven are nonessential, meaning your body produces them on it’s own, and nine are essential, meaning your body needs to acquire them from the external environment. (FDA)

We acquire essential amino acids from many different sources, like

  • meat
  • fish
  • poultry
  • eggs
  • dairy products
  • legumes
  • grains
  • veggies
  • nuts and seeds
  • soy products

Out of the nine essential amino acids, the three branched-chain amino acids (BCAAs) are critical for your muscles.

One of the three is called leucine, and is of particular importance because it reliably increases muscle protein synthesis. (Examine) (MacLean)

The discussion on complete and incomplete proteins fuels the entire debate over whether athletes can get enough protein from plants for optimal performance.

Those who argue that you can get all the protein you need from plant-based protein say that by combining lots of different plant-protein sources, you can achieve a complete protein.

By evaluating the chart below (Examine), it’s easy to see why this is an obvious conclusion to come to. In red, you’ll see which popular plant-based protein lacks an amino acid, as well as another protein that could complement it.

Amino Acids: Requirements of Adults and Contents of Proteins
Amino Acid mg/kg/day* mg/g of protein
Requirement Milk Pea Rice Soy Whey
Histidine 10 15 30 17 24 26 21
Isoleucine 20 30 50 54 40 43 59
Leucine 39 59 97 97 88 80 116
Lysine 30 45 80 83 33 60 102
Methionine 10 16 27 5 29 10 23
Cystine 4 6 9 14 17 12 20
Methionine + Cysteine 15 22 30 8 39 14 36
Phenylalanine + Tyrosine 25 30 99 94 111 90 66
Threonine 15 23 47 43 38 37 76
Tryptophan 4 6 13 11 14 13 20
Valine 26 39 58 81 55 44 58
*Milligrams (of a given amino acid) per kilogram (of body weight) per day
Sources: Protein and Amino Acid Requirements in Human Nutrition, page 245, table 49 (World Health Organization, 2007); Douglas Kalman, "Amino acid composition of an organic brown rice protein concentrate and isolate compared to soy and whey concentrates and isolates" (Foods, 2014 Jun); Stefan Gorissen et al., "Protein content and amino acid composition of commercially available plant-based protein isolates" (Amino Acids, 2018 Aug); USDA Food Composition Databases (accessed: 2018 Sep)


Plant-based proponents point out that, for example, rice doesn’t have enough lysine, but has plenty of methionine, while soy has the opposite problem.

Cook up a meal of brown rice and tofu, and voila! You’ve got yourself the amino acid equivalent of a steak dinner. It certainly makes sense.

And research suggests that vegans don’t have to worry about getting the perfect combination in every meal. It appears that the liver stores amino acids throughout the day. (Palmer)

Yet those who are skeptical of a plant-based diet argue that more factors need to enter the calculus.  

To better understand the issue, let’s compare plant protein and whey protein.

Plant protein vs. whey protein

plant protein vs whey protein

Amino acid profiles of common protein sources

To help everyone make sense of amino acid profiles and the quality of protein ingested, researchers developed the protein digestibility-corrected amino acid score (PDCAAS).

The PDCAAS is a method of evaluating the quality of a protein based on both the amino acid requirements of humans and their ability to digest it.

The scale runs 0-1, with zero being low and 1 being high.

Protein Source


Whey protein


Cow’s milk


Soy protein






Pea protein concentrate


Black beans


Hemp seed









(House, et. al) (Hoffman)

Researchers believe PDCAAS may overestimate a protein’s bioavailability.

Recently, a new scale has been proposed: digestible indispensable amino acid score (DIAAS).

DIAAS differs in that it assesses protein absorption after it leaves the small intestine, with researchers suggesting it is a more accurate measurement.

The chart below, accessed from Examine, shows how the two scores differ.

DIAAS and PDCAAS scores of various proteins
Protein Powder DIAAS PDCAAS
Milk protein concentrate 1.18 1.00
Whey protein isolate 1.09 1.00
Whey protein concentrate 0.973 1.00
Soy protein isolate 0.902 0.99
Pea protein concentrate 0.822 0.893
Rice protein concentrate 0.371 0.419
Source: Shane Rutherfurd et al., "Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores differentially describe protein quality in growing male rats" (J Nutr, 2015 Feb)


The proposed new scale, DIAAS, clearly shows that animal-based protein powders as the most optimal protein source, with soy protein being a close second.

Plant-protein: why it’s more complicated than it appears

The DIAAS scale takes into account bioavailability, amino acid profile, and digestibility.

It doesn’t look at the effects of exercise or digestion speed or glucose production (energy production).

However, we are aware of a few negatives when it comes to plant protein.  

Digestion issues 

Plant proteins seem to make it more difficult to digest available protein. One review notes, “The presence of high levels of dietary trypsin inhibitors from soybeans, kidney beans or other grain legumes have been reported to cause substantial reductions in protein and amino acid digestibility (up to 50 %) and protein quality (up to 100 %) in rats and/or pigs.

Similarly, the presence of high levels of tannins in sorghum and other cereals, fababean and other grain legumes can cause significant reductions (up to 23 %) in protein and amino acid digestibility in rats, poultry, and pigs.” (Sarwar).

Reduced protein synthesis & muscle growth

One study found that whey protein promoted more muscle growth. Researchers concluded, “Compared to soy, whey protein is higher in leucine, absorbed quicker and results in a more pronounced increase in muscle protein synthesis.”

They reported that “Lean body mass gains were significantly (p < 0.05) greater in whey (3.3 ± 1.5 kg) than carb (2.3 ± 1.7 kg) and soy (1.8 ± 1.6 kg),”

and concluded that:

“Despite consuming similar calories and protein during resistance training, daily supplementation with whey was more effective than soy protein or isocaloric carbohydrate control treatment conditions in promoting gains in lean body mass.

These results highlight the importance of protein quality as an important determinant of lean body mass responses to resistance training.” (Volek)

Another study found that a dairy-rich breakfast compared to a soy-rich breakfast stimulated more protein synthesis. (Gran)

Despite these studies, more research is needed. It could very well be that these deficiencies could be overcome simply by ingesting greater amounts of plant proteins.

Or perhaps plant-based protein powders simply need to add methionine, lysine, and leucine.

Plant-based diets and deficiencies

Plant-based diets and deficiencies

Vegan and vegetarian athletes can be at risk for deficiencies. These include

  • Vitamin B12
  • Calcium
  • Iron
  • Zinc
  • Iodine
  • Vitamin D
  • long-chain n-3 fatty acids EPA and DHA


Below is a table complied to aid vegans in getting these nutrients.

Table 4

Vegan-Friendly Food Sources


Vegan-friendly sources


Pulses, grains, legumes, tofu, quinoa, nuts, seeds, vegetables


Flax seeds, walnuts, chia seeds, hemp seeds


Seaweed, algae


Microalgae oil, seaweed

Vitamin B12

Supplements, fortified foods, plant milks, nutritional yeast (fortified), fermented soyb, mushroomsb


Legumes, grains, nuts, seeds, fortified foods, green vegetables


Beans, nuts, seeds, oats, wheat germ, nutritional yeast


Tofu (calcium set), fortified plant milks and juice, kale, broccoli, sprouts, cauliflower, bok choi


Seaweed, cranberries, potatoes, prunes, navy beans, iodized salt

Vitamin D

Lichen-derived D3 supplements

-EPA can also be enzymatically converted from ALA and retroconverted from DHA [83, 84]

-Might not be a reliable source of this nutrient


You can find a breakdown of daily meal plans that cover these deficiencies here.

Best plant-based protein powders

best plant based foods for protein

When considering a plant-based protein, consider a plant blend over a protein derived from one plant.

Hemp may be trendy, but it could leave you lacking essential amino acids.

Find a plant protein supplement with pea and rice. The amino acid profile of a 70:30 pea:rice protein blend is similar to that of whey. (Examine)

You may even want to look for a plant-based protein powder that has added vitamin B12, calcium, iron, and zinc. You may also consider supplementing with a daily vitamin.

Is soy protein good for me?

Debates over soy are passionate and contradicting. A lot of the debate over soy occurs because of a compound found in soy and soy products: soy isoflavones.

These isoflavones are structurally very similar to estrogen, and therefore display some properties of estrogen in the body. (Leaf)

For an excellent discussion on soy isoflavones and its effect on the body, read this discussion.

Is a plant-based diet healthier?

This is a hard question to answer.

What’s clear is that we evolved to function as omnivores. We also know we need lots of protein and some fat to perform at our highest level.

It’s also pretty obvious that whey protein promotes optimal performance gains.

While plant-based protein isn’t optimized, it is effective. And based on observational studies, folks on a plant based diet have a lower BMI and better cardiovascular health.

It’s also clear that a plant-based diet is overall better for the environment.  

However, athletes on a plant-based diet may struggle to get enough protein, vitamin B12, calcium, zinc, and iron.  

Should athletes use plant protein?

should athletes follow a vegan diet

That answer depends on you.

If you have ethical or environmental reasons for not eating meat, then a plant-based diet supplemented with plant protein is likely a great choice for you.

If you are considering a vegetarian diet to lose weight, research does show a correlation between a lower BMI and a plant-based diet.

There are a lot of strong athletes who only fuel with plant-based athletes.

But there are also athletes like Zach Bitter, who holds the American World Record in the 100 mile race and Pete Jacobs, who won the 2012 Ironman on a carnivore (meat-only) diet.

And then there are athletes like Lael Wilcox (endurance cyclist) and Courtney Dauwalter (ultra-runner), who’s sport of choice makes it impossible to follow any kind of strict diet.

Reportedly, they eat anything and everything they can get their hands on.

Dauwalter wins 200-mile foot races outright, fueled by quesadillas and candy. Wilcox can be seen chugging half & half and stuffing french fries into her bike bags. And guess what?

They kick ass, too.

And yet, every vegan swears by being vegan, and every carnivore swears by being a carnivore.

It seems that when it comes to diet, only one thing is certain: athletes perform at a top-level when they adhere to just about any diet that promotes general health.