Many people consider whey to be the hands-down, gram-for-gram winner in the world of protein powders. Quick digestion, high branched-chain amino acid content, great effects on protein synthesis—it’s hard to debate the billing. But unlike boxing managers who duck some fighters for fear of an upset, we’re not afraid of a little competition. As such, we’re tossing all four of the top proteins into the ring for a no-holds-barred, fact-by-fact fight for the ages.
You, the huddled masses yearning to be ripped, crave an authoritative protein champ. Like fight fans, you probably have your loyalties. Some of the old troops who long for the days of Ali and Frazier might still be clinging to egg white protein for their fix. Others might be fond of the new-school science that favors casein, whose steady Oscar de la Hoya-like reliability has been enough to fortify their physiques. And then there are those of you who are starting to root for the underdog. Despite its less-than-impressive ring record, soy—like a surging contender—is a protein on the rise and has scored some impressive victories of late. But like the great Marciano, whey’s dominance in this division of sports nutrition has been unrivaled, until now.
A complete protein is composed of 20 different amino acids, and some of those are more critical than others. At the top of that list are the branched-chain amino acids (BCAAs) that include leucine, isoleucine and valine, which are musts for protein synthesis, the process by which muscle fibers grow. Arginine is crucial for stimulating production of nitric oxide (NO), which has numerous vital properties for muscle growth, such as increasing blood flow to muscles to deliver more nutrients, anabolic hormones and oxygen for better recovery and greater muscle protein synthesis. Glutamine is also high on the list because, along with a multitude of other benefits, it keeps muscle protein synthesis high and muscle protein breakdown low. In a hard-fought opening round for amino acid content supremacy, check out the tally:
- No. 1 Whey: Due to its higher content of BCAAs—particularly leucine, the most critical amino for stimulating protein synthesis—whey is the clear winner in this opening round.
- No. 2 Soy: The highest of the four in arginine content, and second to whey and casein in leucine and glutamine contents, respectively, soy comes in second.
- No. 3 Casein: The highest in glutamine, casein comes in third. It’ll have to put up a stronger fight moving forward if it expects to stay in the hunt.
- No. 4 Egg White: Although egg white has a great overall amino acid mix, it’s highest in none of the most critical amino acids but is second to soy in arginine.
The true test of a protein is bioavailability—how much of its critical aminos actually make it to the muscles. To measure this, scientists use the protein digestibility corrected amino acid score (PDCAAS). It takes into consideration the amino acid content of the protein and its digestibility, which ensures the aminos get to muscles. Proteins that meet the amino acid and digestibility requirements for humans get a PDCAAS of 100%. All four proteins featured here meet the requirements for humans. In other words, they’re high-quality protein sources unlike, say, black beans, which get an 84%. Here’s how the battle of bioavailability shakes out:
- No. 1 (Tie) Whey, Casein, Soy and Egg White: The PDCAAS of each protein is 100%.
For bodybuilders, the No. 1 reason to use protein powders is to boost muscle growth. But you may be surprised to find that some of the proteins have multiple health benefits. Time for the underdog to flash its health assets:
- No. 1 Soy: Soy reigns in the top spot here in the third. Not only does it protect against cardiovascular disease, but the FDA-approved health claim for 25 grams of soy protein daily reduces the risk. Soy is also beneficial in protecting against numerous cancers such as colorectal, breast and prostate.
- No. 2 Whey: Although the extra health benefits of soy may not get some bodybuilders to use it more often, many guys will be happy to know that the whey protein they love for mass-gaining also does a body good. For starters, because it comes from milk, it’s a good source of calcium, which enhances bone and dental health as well as aids fat loss. Whey was also recently found to reduce the risk of cardiovascular disease via its ability to lower blood pressure and increase blood vessel dilation, which has muscle-building effects. In addition, whey enhances the body’s levels of a critical antioxidant known as glutathione and may even help ward off certain cancers. Whey protein also lowers LDL (bad cholesterol) levels.
- No. 3 Casein: Similar to whey, casein contains beneficial peptides that help lower blood pressure; it’s also a good source of calcium. Not bad, but not enough to climb ahead on the scorecards.
- No. 4 Egg White: There’s little research on the specific health benefits of egg white protein, putting it in last here.
Protein builds muscle by increasing the process of protein synthesis. Therefore, bodybuilders should be taking protein powders that maximize protein synthesis. During a protein synthesis-heavy fourth round, here’s how the challengers stack up:
- No. 1 Whey: The landmark 1997 French study from the Universite Clermont Auvergne reported that due to whey’s rapid digestion, it leads to significantly higher protein synthesis than casein. Although the other proteins weren’t directly compared, it can be assumed that since they aren’t as rapidly digested as whey, they don’t stimulate protein synthesis as significantly.
- No. 2 Soy: There’s some controversy over soy’s effectiveness in stimulating protein synthesis and therefore muscle growth, but in this round soy played to its strengths. Research on both bodybuilders and rats has shown soy is about as effective as whey at stimulating muscle growth. Yet research also shows that due to the slightly lower BCAA content of soy compared to whey, soy doesn’t activate critical factors involved in protein synthesis as well as whey does.
- No. 3 Casein: Although casein was shown to be less effective at stimulating protein synthesis at rest in the 1997 French study, more recent research from the University of Texas Medical Branch (Galveston) reports that casein may be just as effective at stimulating protein synthesis postworkout as whey.
- No. 4 Egg White: Research shows that egg white protein has similar effects on stimulating protein synthesis as milk protein in certain populations. Although it has a decent amount of BCAA content, its ability to drive protein synthesis isn’t as effective as that of whey.
A protein’s ability to stifle muscle protein breakdown is very important. That’s because muscle growth is the result of the delicate balance between protein synthesis and protein breakdown. The more synthesis and less breakdown you have, the more muscle growth you’ll experience. Here’s how the four proteins stack up for limiting muscle protein breakdown:
- No. 1 Casein: The French study mentioned in Round 4 also discovered that casein was superior at blunting muscle protein breakdown. This is due to its slow and steady rate of digestion, which means it delivers a continuous supply of aminos to muscle cells. Because of this, casein comes in at No. 1 here.
- No. 2 Egg White: The digestion rate of egg white protein isn’t quite as slow as casein’s, but it’s also not nearly as fast as those of whey or soy. This likely leads to egg white’s ability to effectively prevent muscle protein breakdown almost as well as casein as shown in clinical trials.
- No. 3 Soy: Soy protein digests almost as rapidly as whey, which means its ability to halt muscle protein breakdown is limited.
- No. 4 Whey: As effective as it is at boosting protein synthesis, whey has little effect on halting muscle protein breakdown, bringing it in at No. 4.
Research shows that the most critical times to take protein powders are immediately before and after workouts. The question many bodybuilders have is, which one at which time? Here’s how they compare as preworkout supplements:
- No. 1 Whey: Whey protein contains components that enhance dilation of blood vessels, which promotes the delivery of nutrients (such as the amino acids it supplies), hormones and oxygen to muscles during exercise. Due to its rapid digestion rate and impact on blood flow, its aminos are quickly available to enhance muscle protein synthesis. Research from the University of Texas Medical Branch (Galveston) shows that rapid delivery of amino acids to muscles immediately before workouts maximizes muscle protein synthesis. This brings whey in at No. 1.
- No. 2 Soy: Soy is beginning to show signs of improvement here in the sixth. Because it has a high amount of arginine (almost 2 grams per 20 grams of soy), it makes a great preworkout protein for boosting NO levels and enhancing dilation of blood vessels. Plus it’s digested almost as rapidly as whey protein.
- No. 3 Egg White: Egg protein is second to soy in arginine content, meaning that it can also help enhance blood flow to muscles via greater dilation.
- No. 4 Casein: Last, but certainly not least, casein is slowly digested, which means it won’t get a boatload of aminos to your muscles fast. It will, however, supply a steady flow that can help stave off muscle breakdown during a workout. It comes in at No. 4 here, but it’s still a valuable protein for a preworkout mix.
It’s vital to get in protein immediately postworkout to stimulate protein synthesis at this critical time. Here’s how the challengers stack up as postworkout supplements:
- No. 1 Whey: Whey boosts insulin higher than the other three proteins. Because insulin is an anabolic hormone that kicks up protein synthesis, it’s ideal to boost it right after a workout. Whey also has the highest levels of leucine, which is critical for muscle growth.
- No. 2 Casein: Although researchers originally thought casein should be the last protein powder to take postworkout due to its slow digestion, more recent science showed it can stimulate protein synthesis as well as whey when taken after exercise. And one study found that adding casein to whey results in significantly more muscle than taking whey alone.
- No. 3 Soy: Research shows that soy protein also leads to a fairly significant boost in insulin levels, just not quite as high as with whey. Soy protein’s high antioxidant component helps protect muscles from oxidative damage, which can lead to less muscle damage and enhanced recovery. Not a bad round for soy.
- No. 4 Egg White: Although egg is a quality protein, it doesn’t significantly boost insulin levels. In addition, not as much research exists on its postworkout benefits.
You essentially undergo a 7-8-hour fast when you sleep. But taking the right protein powder before bed can make all the difference in muscle mass. Which one makes bedtime its business?
- No. 1 Casein: Casein sends the other three proteins to the mat in this round. Because it’s the slowest-digesting protein powder you can buy, casein is the best choice to take right before bed. This helps supply your body with a slow drip of amino acids that can be used as fuel throughout the night, meaning your body won’t turn to muscle aminos for fuel. And any amino acids from the casein not needed for fuel can boost muscle growth.
- No. 2 Egg White: Although the digestion rate of egg white protein isn’t nearly as slow as casein, it’s also not as fast as whey’s or soy’s. Since this round is about how slowly a protein digests, egg white comes in at No. 2.
- No. 3 Soy: Due to its rapid rate of digestion, soy makes a poor bedtime protein source. Still, it’s in better shape than whey protein.
- No. 4 Whey: Though whey has dominated the scorecards up to this point, it lost steam here in the eighth. As the fastest-digesting protein powder out there, it’s the worst possible nighttime protein.
For some guys, benefits of certain protein powders are moot if they don’t taste good and go down easy. This round compares the availability of flavors of each protein as well as their ability to mix easily in water. In the taste round, whey begins to pull away:
- No. 1 Whey: Whey is highly soluble, meaning it dissolves well in liquids. It not only mixes well but also works with numerous flavors, such as the standard chocolate and vanilla plus fruity flavors such as watermelon. Whey protein comes in the widest range of flavors, making it No. 1 in palatability.
- No. 2 Soy: Close to whey in solubility, soy protein mixes fairly well in fluids. This allows availability in a variety of flavors, especially with the more recent boom in the popularity of soy.
- No. 3 Egg White: Egg protein is much less popular today than it was before whey’s domination, which means you can usually find it only in the standard chocolate, vanilla and maybe strawberry. Still, it mixes fairly well in water.
- No. 4 Casein: The reason casein is a slow-digesting protein is because it forms clumps in the stomach. When you add it to a glass of water it does the same thing, making it hard to mix in water and sometimes difficult to consume. Manufacturers are making more flavors due to casein’s sudden popularity surge, but it’s still limited in the available flavor category.
Last and certainly not least for most guys when it comes to protein selection is price. Everyone would like to fork out $50 to listen to Jim Lampley call the blow-by-blow action on HBO pay-per-view, but sometimes you have to settle for the basic cable clashes on ESPN’s Friday Night Fights. Budgets for protein powders are similar—of course you want the best, but ultimately it has to be affordable. Here’s how our contenders stack up on price:
- No. 1 Whey: The economics of whey protein is simple supply and demand. Demand for whey increased so much that supply eventually overshot it, leaving a ton of whey available and causing prices to drop dramatically. Today you can get a straightforward whey protein fairly inexpensively, with most 2-3-pound tubs coming in between $25 and $40. Let’s see the other proteins slip that punch.
- No. 2 Soy: Before the benefits of soy were recognized, it was simply considered a cheap protein. With more demand for soy today and better manufacturing processes that allow the production of higher-quality soy isolates, soy prices have come up. Yet it’s still a fairly inexpensive protein.
- No. 3 Casein: Once a fairly cheap protein, casein is a bit more expensive today. That’s due to the more widely known value of slow-digesting proteins and the ability of manufacturers to create extremely slow-digesting caseins such as micellar casein. This brings casein in at No. 3 in the price round.
- No. 4 Egg White: Egg white protein always has been—and still is—a high-quality but expensive protein.
The scorecards are in. For the particulars of the decision, let’s go back to our official ring announcer Michael Buffer: “Ladies and gentlemen—a round of applause for all four of these fantastic protein options. After 10 rounds of heated and informative scientific debate, we go to the scorecards. Meeting or exceeding the criteria for a quality protein in nearly every conceivable category and coming in with the lowest tally tonight is the newly crowned, undisputed protein champion of the world—whey protein!”
Thanks, Mike. Now here’s your peek at the scorecards. Remember, the low score wins.
- No. 1 Whey (17 points)
- No. 2 Soy (21 points)
- No. 3 Casein (25 points)
- No. 4 Egg White (31 points)
Although whey protein was the solid winner in our bout, it doesn’t mean you should buy whey as your only protein. Each of the four proteins has specific benefits unique to it.
For those on a budget who can afford just one type of protein, your best bet is a whey protein powder. But if you can afford it, consider buying a jug of whey, a jug of soy and a jug of casein, and use about 10-15 grams of each whenever you take your protein. Or check out a protein that already provides a mix of these three. Either way allows you to take advantage of each protein’s high points.
As you can see, egg white—the defiant Evander Holyfield of protein that simply won’t go quietly into that good night—may have been at its best years ago but is still a beneficial protein. Most bodybuilders likely get enough egg white protein from breakfast, but if you don’t, consider also buying an egg white protein and adding it to your protein mix, or getting a mixed protein with egg white protein in it.
So in summary, don’t ignore soy, casein and egg white. Just make sure you have whey fighting for you every day in your physique pursuits.
BY JIM STOPPANI, PHD