What is the “Best” Protein?

Dr. Shawn Talbott (Ph.D., CNS, LDN, FACSM, FACN, FAIS) has gone from triathlon struggler to gut-brain guru! With a Ph.D. in Nutritional Biochemistry, he's on a mission to boost everyday human performance through the power of natural solutions and the gut-brain axis.

Of all the nutrition questions that I’m asked, one of the most common is about the “best” type of protein. My first response is typically to ask the person “best for what?” – because the answer to the “best” protein question tends to differ depending on what you want the protein to be doing in your diet.


If you’re simply looking for a source of protein calories, such as to serve as a meal replacement, then almost any type of protein will do the trick (whether from casein, whey, egg, soy, rice, hemp, pea, and a variety of other sources). However, if you want the protein for a specific purpose such as weight loss, or muscle mass, or appetite control, or exercise recovery, then you can maximize your benefits by selecting the “correct” protein for the desired effect. You may also have to consider other factors such as whether or not you’re able to digest lactose (the sugar in milk) which will be found in milk protein isolates and in most whey protein concentrates (but not in highly purified whey protein isolates or non-milk proteins such as soy). If you’re a vegetarian, then whey protein (from cow’s milk) is certainly not going to be the “best” choice for you. If, like a lot of people including my son, you’re allergic to casein (also from cow’s milk), then that is not a great option for you. 


When it comes to the “best” protein, there is a lot more to consider than simply the source (casein, whey, soy, etc) and the amount (how many grams per serving). Discussions of the value of protein supplements have become a great deal more complicated in the last several years. This is due not to the debate concerning whether or not athletes or dieters require greater dietary protein intakes compared to their sedentary or non-dieting counterparts (the scientific consensus is quite clear that athletes and dieters clearly benefit from increased protein intake) – but rather to the explosion in marketing of various forms of protein fractions as casein, whey, soy, and many others. The protein debate has slowly changed from “how much?” to one of “which protein is best?” – with no shortage of opinions.


If you look closely at the scientific research, there is very good evidence that protein needs are elevated by exercise training, infection, and periods of acute and chronic stress – including the “stress” of caloric restriction for weight loss. Some of the best evidence comes from studies of competitive athletes, in whom protein needs are nearly doubled during periods of intense training and competition. Athletes competing in power or strength sports probably require about 1.6 grams of protein per kilogram of body weight, while endurance-trained athletes may need about 1.3 grams per kg. This ends up working out to about 0.6-0.75 grams of protein per pound of body weight – so a 140lb “dieting” woman might need 80-90 grams of protein per day while a 200lb “dieting” man might need 120-150 grams per day.


Here is a “cheat sheet” (with detailed discussion below) to help you determine the “best” protein for a particular benefit…



Desired Effect

Best Protein

General Nutrition

Soy Protein Isolate (water-extracted to retain naturally-occurring isoflavones)

Weight Loss (fat loss & muscle maintenance)

Whey Protein Isolate (WPI)

Appetite Control

Whey Protein Hydrolysate (WPH) – taken between meals

Muscle Growth

Whey Protein Hydrolysate (WPH) – taken before resistance training

Slowing Muscle Breakdown

Casein – taken before bedtime

Post-Exercise Recovery

Glutamine & BCAAs (branched chain amino acids = valine, leucine, isoleucine)




General Nutrition (Soy Protein Isolate)

Soy protein has been criticized by some nutritionists as being an “inferior” dietary source of protein – but such criticisms are unfounded for the more modern purified soy protein isolates (90%-97% protein) that are currently marketed as dietary supplements. 


Soy protein has primarily been studied for its benefits in reducing hyperlipidemia (high cholesterol), slowing bone loss, alleviating menopausal symptoms (hot flashes), and preventing cancers of the breast and prostate. Some, but not all, of the beneficial effects of soy protein appear to be due to the presence of antioxidant/flavonoid phytonutrients called isoflavones (primarily daidzein and genistein). 


The vast majority of studies that have investigated the health effects of soy protein, have looked at various indices of heart disease and osteoporosis, so soy protein should be thought of more as a “general health” protein than as a specific approach to fat loss or muscle maintenance (where whey appears to be much more effective).


Soy protein is considered to be quite safe – with as much as 60 grams of protein containing 90mg of isoflavones being used with no adverse effects in studies of up to one year. When selecting a soy protein, be sure to look for a “water-extracted” soy protein isolate, which avoids the use of harsh chemical extraction methods and retains a higher level of the naturally-occurring isoflavones that have been linked to reduced cancer rates.


Weight Loss (Whey Protein Isolate)

Keep in mind that whenever I use the term, “weight loss” I’m referring to a specific loss of fat with maintenance of lean/muscle mass. You can follow lots of diets that result in massive weight loss from water and muscle mass in just a few days – but that is neither healthy nor sustainable.


Whey is one of the proteins found in milk (the other is casein). Whey protein accounts for only about 20% of the total protein found in milk, while casein makes up about 80% of milk protein. Long considered a useless by-product of dairy (cheese) manufacturing, whey protein is enjoying an increased interest as a protein supplement.  Because whey protein includes a variety of immunoglobulin compounds (alpha-lactalbumin, beta-lactoglobulin, lactoferrin, albumin, and immunoglobulins A, G and M), whey supplements are often touted as effective in boosting immune protection and enhancing post-exercise recovery. Whey protein also contains lactoferrin, a protein that has been shown to possess bacteriostatic and bactericidal activity against microorganisms that can cause gastroenteric infections and food poisoning.


Whey protein also contains approximate 20-30% of its amino acid content as branched chain amino acids (BCAAs = leucine, isoleucine, and valine) – which can be readily oxidized by the muscle as energy and may be associated with a delay in fatigue during long-duration exercise, especially in the heat.


In addition to its high content of immunoglobulins and BCAAs, whey protein is also a rich source of cysteine – an important amino acid constituent of the endogenous antioxidant glutathione. Intense exercise is known to reduce cellular glutathione levels – so high-cysteine whey protein supplements may be an effective approach to restoring glutathione levels in the body.


It is important to note that commercial whey proteins can differ dramatically from one another depending on the processing method and the total protein content. For example, whey protein can exist as simple whey powder (30% or less total protein content), whey protein concentrate (30-85% protein) or whey protein isolate (90% or higher protein content). In the case of whey protein isolates (the most expensive type), two key processing methods, ion exchange filtration and cross-flow micro-filtration, can remove different components of the total whey protein, resulting in end products with different taste, texture and functional properties. Whey proteins processed using the ion exchange methodology appear to retain the majority of the functional benefits associated with immune system maintenance. 


Whey protein has been used in a number of animal and human feeding studies, where it has shown benefits in promoting fat loss, stimulating muscle gain, elevating glutathione levels, and preventing metabolic acidosis (although this effect can be claimed for virtually any high-quality protein source). When compared to other protein sources (casein and soy), whey protein isolate is significantly more effective in terms of fat loss and muscle gain benefits across a wide range of scientific studies (athletes/dieters).


Appetite Control (Whey Protein Hydrolysate)

Whey protein isolate (WPI – as discussed above) is sometimes referred to as a “fast protein” to indicate its faster rate of digestion and absorption compared to proteins such as casein which are digested at a “slower” rate. Whey Protein Hydrolysate (WPH) is whey protein isolate that has been “hydrolyzed” – or partially digested with enzymes – to result in a blend of shorter protein chains (peptides) which have even faster digestion and absorption than the already-fast WPI. This means that in addition to serving as an excellent source of fat-burning/muscle-building whey protein, WPH has the additional benefit of working fast. This rapid speed of absorption of di- and tri-peptides into the bloodstream also sends two very important signals – one to the brain (reducing appetite) and another to muscles (stimulating protein synthesis). This direct appetite-reducing effect makes WPH an outstanding part of a “between-meal” snack (such as a bar) to help reduce cravings from one meal to the next. 


Muscle Growth (Whey Protein Hydrolysate)

Taken before resistance training (to maximize delivery of the protein peptides to the working muscles), WPH rapidly stimulates protein synthesis (muscle building). See the discussion above regarding the appetite-controlling benefits of WPH. When choosing a WPH, look for a “high-DH” version (DH = “degree of hydrolysis”) which indicates a high concentration of the specific di- and tri-peptides that are associated with the appetite and muscle building effects of WPH.


Slowing Muscle Breakdown (Casein)

Casein is the “other” protein in milk (along with whey) – but whey gets a lot more attention because of its benefits for fat loss and muscle maintenance. When taken before bedtime, casein (as a “slow” protein) can have some amazing benefits in slowing the “catabolic” (breakdown) effects of overnight fasting (where muscle mass can be lost in hard-training athletes). The average non-athlete who is interested in protein for weight loss or general nutrition can probably skip the nighttime casein – but the “slow trickle” delivery of amino acids from casein can help to slow muscle loss – which, for a high-level athlete can make a meaningful difference in muscular size, power, and athletic performance.


Post-Exercise Recovery (Glutamine & BCAAs)

Whey protein isolate (WPI – see above) is a rich source of essential amino acids including glutamine, cysteine, and the 3 BCAAs. There is growing evidence that specialized amino acid mixtures based on essential or semi-essential amino acids (and above and beyond what can be provided by whey protein supplements), can be especially beneficial for promoting post-exercise recovery, stimulating muscle growth, and accelerating wound healing (especially of soft tissues such as muscles, tendons, and ligaments). For hard-training athletes, exercise recovery can be enhanced by increased intake of 4 specific amino acids; glutamine and the 3 branched-chain amino acids (valine, leucine, isoleucine). Benefits shown in research studies of glutamine/BCAAs include reduced muscle soreness, improved immune system function (fewer upper-respiratory tract infections), increased energy/mood levels, and faster return to “normal” levels of intense training after competition. As with nighttime casein described above, the average dieter or health enthusiast can probably skip the use of post-exercise glutamine/BCAAs – but competitive athletes who are training hard on a daily basis will find that the speedier recovery that comes with glutamine/BCAAs means a higher level of performance in both training and competition.



I hope some of that helps you choose the “best” protein for your particular needs. Just keep in mind that if you’re looking for “general nutrition” go for a high-quality soy protein isolate. If you’re looking for weight loss (fat loss plus muscle maintenance), go for a whey protein isolate. For maximal appetite-controlling and muscle-stimulating effects, go for a whey protein hydrolysate (take it between meals for the appetite effects and before workouts for the muscle effects). Lastly, for competitive athletes, post-exercise consumption of glutamine/BCAAs can enhance recovery.


Thanks for reading. Let me know your comments below – including any other nutrition/fitness topics you’d like me to cover…


In health,




About the Author: Dr. Shawn Talbott holds a MS in Exercise Science (UMass Amherst) and PhD in Nutritional Biochemistry (Rutgers). As an avid endurance nut (15 Ironman triathlons, 8 ultramarathons, and dozens of marathons and Olympic-distance triathlons), he eats all of these protein sources in abundance.



About the Author

Exercise physiologist (MS, UMass Amherst) and Nutritional Biochemist (PhD, Rutgers) who studies how lifestyle influences our biochemistry, psychology and behavior - which kind of makes me a "Psycho-Nutritionist"?!?!

  • Lots of research has been done on soy protein. A long time ago, soy isolate (high quality protein extracts) are only used in industrial applications. They are added to foods and other supplements to boost the nutritional value of the products. It wasn’t until the late 1990s that this wonderful plant protein is introduced to the general public.”

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