Your Comprehensive Guide to Whey Protein, Pea Protein and Rice Protein

Whether you’re a hard-core exercise fanatic, a desk-bound professional, or a health-conscious mom, it’s crucial to have plenty of protein throughout the day. Proteins are one of the most important nutrients in the diet. In fact, the word protein comes from a Greek word meaning “of first importance.” They are used in virtually every process within the body. All the tissues of the body are made primarily of proteins. This includes muscle, bones, organs, connective tissue; ultimately proteins are the stuff we’re made of. Proteins govern metabolism and gene repair. They are also used to carry signals from one part of the body to another, to support immune responses, and are important for hormone and enzyme production. 

Whey Protein As The "Gold Standard"

Traditionally, animal-based proteins have been the go-to supplement for anyone interested in optimizing protein intake. Whey protein dominates the options, and is generally considered the “gold standard” for meeting the complete protein needs of all the essential amino acids in adequate amounts. 

There is a significant difference between the whey protein forms, their bioavailability and cost. The more heat and pressure used in the manufacturing, and the faster whey protein is made, the less bio-available the protein. Although less expensive to manufacture, whey manufactured in this manner results in a much lower quality, more poorly utilized product that yields inferior results.

The highest quality whey protein is manufactured at a lower pressure, lower temperature, and a slower manufacturing rate. This is much more bio-available and yields far superior results. Since the time required to manufacture the highest quality whey protein is longer, it’s a more costly process. Simply put, high quality whey protein costs more than low quality whey protein.

Three Basic Forms of Whey Protein

  • Whey Protein Isolates yield a higher percentage of pure protein and can be filtered enough to be free of lactose, carbohydrates, fat, and cholesterol.  This means everything beneficial about the protein is left intact, while removing most of the unwanted leftovers.  This is the most expensive, but has the highest level of bioavailable protein.  
  • Whey Protein Concentrate is usually the better tasting of the three and usually the least expensive because it requires the least amount of filtration, it also has the highest lactose (milk sugar) and fat content of the whey proteins. 
  • Whey Protein Hydrolysate is a pre-digested form of whey protein usually from Isolate, that utilizes enzymes to partially hydrolyzed or digest the protein. This protein has the least amount of fat and is lactose-free. It is widely considered to have the least favorable taste.

The quality of the protein cannot be determined by simply looking at the label. The level of protein grams per serving could be exactly the same, but the higher quality protein is virtually 100% bioavailable, whereas the low-quality protein can be as low as 20-30% bioavailable, sometimes less. In addition, some protein products may contain the more costly, high quality whey protein or whey protein isolate, but blend it with lower-cost, lower-quality whey proteins, so while the labeled ingredients look promising, this formulation is diluted in quality, potency and benefits. (1)

Many studies confirm the benefits of whey proteins. One study showed if a high amount of whey protein is consumed, levels of ghrelin, a hormone that signals the brain you are hungry, is reduced. This results in a full and satisfied feelings for longer periods of time. (2)

In addition, various studies indicate that consumed in small amounts prior to a meal, whey protein improves post-meal glycemic control. (3) Whey is shown to be higher in leucine (a branched chain amino acid), absorbed more quickly and produces a more pronounced increase in muscle protein synthesis to help build and maintain lean muscle. (4) (5) These studies also indicate an ability to blunt cortisol stress, and may affect brain function and influence behavior by inducing the synthesis of neurotransmitters, resulting in beneficial cognitive performance and elevated mood. (6) 

Here are 11 top reasons to include protein in your sports nutrition diet

Cons of Whey Protein

Some downsides are noted by users and researchers. Whey protein can be difficult to digest for some individuals, leading to flatulence, diarrhea and bloating. Some whey proteins are heavily processed, which can degrade the nutritional quality of whey – including the quality of the protein itself. Additionally, to make whey palatable, some manufacturers fill whey products with artificial sweeteners. And finally, with few exceptions, whey is from cows that are given a variety of hormones and medications including antibiotics to maximize their milk production. Although a growing number of manufacturers are now offering whey proteins from grass-fed, organically raised cows, at this time a much smaller fraction of the proteins on the market come from cows that actually eat grass, and instead are given a diet of soy and corn grown with unnatural fertilizers. (7,8,9)

On the other hand, there has been a growing move toward plant-based protein powders. Although whey protein is still the current market leader, and for good reason, plant proteins are gaining share. (10) 

Pea Protein Powder

Pea and rice proteins are highly viable alternative sources of protein. With careful attention, they can supply a balanced, full spectrum of amino acids in a highly absorbable, bioavailable form. For vegans and those allergic to certain animal-based proteins, they offer a practical alternative.

Pea and rice proteins are easily digested and assimilated. They digest slowly to give a long-lasting protein/amino acid benefit to support lean mass, including bone, muscle, connective tissue and all the tissues of the body. High quality pea and rice proteins are processed at a low temperature to ensure easy digestion and rapid absorption.

Pea protein comes from the yellow split pea and is very easy to digest. It has a possible protein content of 80%, which is moderately lower than brown rice at 90% and whey isolate at 95%. It also absorbs quickly, making it a good choice to have immediately after a workout. (11)    

Pea protein is a good vegetable protein source of the essential amino acid Lysine, which cannot be made in the body and must therefore be consumed through the diet. Lysine can be particularly deficient in vegan/vegetarian based diets. Lysine also appears to help absorb calcium and plays an important role in the formation of collagen—the building block of connective tissue such as bones, cartilage, skin and tendons. Pea protein is an outstanding non-dairy source of amino acids for the body and enhances a positive nitrogen balance, which is essential for tissue repair and recovery. (12)

Rice Protein Powder

Rice protein is manufactured to separate the proteins from the carbs associated with rice, and has the added benefit of being gluten-free, and high in fiber and Vitamin B. A typical product may contain anywhere from 20 to 24 grams of protein per one scoop serving, which is only slightly less protein than whey isolate. Brown rice protein has been clinically proven to be the equal of whey as a supplement for strength training. (13)

Rice protein contains high levels of the essential amino acid Methionine, which can also be deficient in vegan/vegetarian based diets. L-methionine is necessary for the production of epinephrine (adrenalin) and the hormone melatonin. Methionine is the precursor of taurine, which has multiple critical functions in the body.  While taurine is present in eggs, seafood and meat, the production of taurine from methionine may be the only source of taurine for the vegetarian or individual on a restricted diet. Taurine is essential for normal function of both the heart muscle and skeleton.  It protects against toxicity from both lead and cadmium. It is also essential for the production of bile acids. (14) 

Lysine and methionine are the precursors of carnitine, the molecule responsible for converting fatty acids into energy and helping lower cholesterol. L-lysine and L-methionine are required to produce L-carnitine, a carrier needed to move fatty acids into the mitochondria where they can be burned to produce energy for the cells. Deficiency of lysine or methionine can cause fatty build-ups in the liver. (15) 

The most common misgiving the consumer has with plant-based proteins is that they tend to be deficient in some amino acids, whereas whey protein has a complete amino acid profile of all nine of the amino acids, and is therefore considered a complete protein. Plants, however, are not complete proteins because they tend to either miss one or more, or be lower in some of the essential amino acids.

One solution seen in the marketplace is to combine plant-based protein sources to fill any potential nutritional gap from a single protein source. A popular combination is brown rice and pea protein. With rice protein high in amino cysteine and methionine, but low in lysine, and pea protein low in cysteine and methionine but high in lysine, this combination provides all the essential amino acids.

Leucine is Necessary For Building Muscle

While whey protein is also promoted for its high levels of branched-chain amino acids (BCAAs), mainly leucine, plant-based proteins contain less leucine than whey protein. Leucine is a key factor in maximizing protein muscle synthesis from resistance training. However, once this leucine level is reached, protein’s ability to increase muscle protein synthesis effectively plateaus. Plant-based proteins contain about 6-8% leucine while animal-based proteins contain about 8-11% The same lean mass and strength improvements can be achieved with either whey or rice protein, provided the dose of rice protein is high enough to provide an effective amount of leucine.  In other words, a higher dosage is simply needed. (16)

Jack Grogan is chief science officer for Uckele Health & Nutrition. He is a recognized expert in hair mineral analysis, a tool in determining the causes of nutritional imbalances and deficiencies. With considerable experience in the fields of biology, biochemistry and nutrition, he has been influential in the development of hundreds of proprietary nutritional formulas and programs.


1. Walzem, R. M., Dillard, C., & German, J. (2002). Whey components: millennia of evolution create functionalities for mammalian nutrition: What we know and what we may be overlooking. Critical Reviews in Food Science and Nutrition, 42 (4), 353-375.

2. Astbury NM, Taylor MA, French SJ, Macdonald IA. Snacks containing whey protein and polydextrose induce a sustained reduction in daily energy intake over 2 wk under free-living conditions. Am J Clin Nutr. 2014 May;99(5):1131-40.

3. Akhavan T, Luhovyy BL, Panahi S, Kubant R, Brown PH, Anderson GH. Mechanism of action of pre-meal consumption of whey protein on glycemic control in young adults. J Nutr Biochem. 2014 Jan;25(1):36-43.

4. Witard OC, Jackman SR, Breen L, Smith K, Selby A, Tipton KD. Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise. Am J Clin Nutr. 2014 Jan;99(1):86–95.

5. Volek JS, Volk BM, Gómez AL, et al. Whey protein supplementation during resistance training augments lean body mass. J Am Coll Nutr. 2013;32(2):122–35.

6. Kraemer WJ, Solomon-Hill G, Volk BM, et al. The effects of soy and whey protein supplementation on acute hormonal responses to resistance exercise in men. J Am Coll Nutr. 2013;32(1):66–74.

7. Swallow DM. Genetics of lactase persistence and lactose intolerance. Annu Rev Genet. 2003;37:197–219.

8. Fischer WJ, Schilter B, Tritscher AM, Stadler RH. Contaminants of milk and dairy products: contamination resulting from farm and dairy practices. In: Fuquay JW, ed. Encyclopedia of Dairy Sciences. 2nd ed. San Diego, CA: Academic Press; 2011:887–897.

9. Baars AJ, Bakker MI, Baumann RA, et al. Dioxins, dioxin-like PCBs and nondioxin- like PCBs in foodstuffs: occurrence and dietary intake in the Netherlands. Toxicol Lett. 2004;151:51–61.

10. [Internet]. Product Report Insights: Plant-based protein powders drove growth

12. [Internet]. Baltimore: The Vegetarian Resource Group; c1995-2013 [cited 2013 Nov 4] Protein in the Vegan Diet.

13. Schmidt JA, Rinaldi S, Scalbert A, Ferrari P, Achaintre D, Gunter MJ, Appleby PN, Key TJ, Travis RC. Plasma concentrations and intakes of amino acids in male meat-eaters, fish-eaters, vegetarians and vegans: a cross-sectional analysis in the EPIC-Oxford cohort. Eur J Clin Nutr. 2015 Sep 23.

14. Monteiro AG, Aoki MS, Evangelista AL, Alveno DA, Monteiro GA, Picarro Ida C, Ugrinowitsch C. Nonlinear periodization maximizes strength gains in split resistance training routines. Journal of strength and conditioning research / National Strength & Conditioning Association. 2009;23:1321–1326.

15. Joy J.M., Lowery R.P., Wilson J.M., Purpura M., de Souza E.O., Wilson S.M., Kalman D.S., Dudeck J.E., Jäger R. The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance. Nutr. J. 2013;12:86–93.

16. Rebouche CJ1, Bosch EP, Chenard CA, Schabold KJ, Nelson SE, Utilization of dietary precursors for carnitine synthesis in human adults. J Nutr. 1989 Dec;119(12):1907-13.

17. [Internet]. Jeff S. Volek, Ph.D., R.D, Do plant proteins build lean muscle as well as whey protein?   


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