Whey Protein vs Casein Protein – Which One is Superior?


Trying to decide on which proteins to use at what times and for what reasons can be a mind numbing process. There are basically two major proteins in the bodybuilder’s arsenal. Those being casein and whey. They are also sometimes referred to as slow and fast acting proteins respectively. The purpose of this article series is to give you an in-depth look at the properties of each of these proteins, explain what it all means and why it is important to you. And, Finally, to provide a systematic way to apply it all.

So you’ve got a choice. Casein or whey? fast or slow? Some people swear by one or the other and would have you believe that one of them is in fact superior.

Well, I am sorry to say that those people are wrong. They either do not understand the literature, have a poor sense of critical application or just want to make an impact by taking a stand. Which ever it may be, these people have misled you. And I can assure you that their path is nothing but a downward spiral to minimal results. To truly get the most from your protein supplementation you will need to utilize both types of protein in your repertoire of supplements

Whey is a by-product of cheese production. When cheese is made, a thin liquid is left over. That liquid is whey and it is less than 1% protein. It is concentrated and dried, and you have a protein powder. Whey protein is considered a “Fast Acting” protein. But what, exactly, is meant by ‘Fast’? Fast refers to the amount of time it takes to be fully metabolized. More specifically, the time it takes for it to be digested(if needed), absorbed into the blood, taken up by a bodily tissue and complete one of many metabolic fates. The two dominant pathways here are the creation of a new protein from the individual amino acids or oxidation into urea and possibly glucose. Urea is the major component of urine, while glucose is the humans basic unit of carbohydrate. With whey protein, it will take only 20 minutes before almost all of what you have consumed is coursing through your veins. Somewhere between 20-40 minutes, the level of amino acids in your blood has reached its high point. With in the hour it will have gone through the various metabolic processes, either protein synthesis, or oxidation (11, 12,13,14). This is a good thing! Muscle growth is dependant on the balance between protein synthesis and breakdown (18). If the synthesis of new muscle protein is greater than the breakdown of muscle protein, net gains in muscle mass are seen. So with whey protein, it will take only 40 minutes for blood levels of amino acids and protein synthesis to reach a peak, and in about an hour they will come back to normal after a single feeding of protein (5,14). This is amazingly fast in comparison to its counter part casein or even whole food.

Casein is considered a “Slow” protein. When you consume casein, you will reach a peak in blood amino acids and protein synthesis between 3 to 4 hours (5,12). However, This ‘peak’ does not even come close to that of whey. On a scale of 1-10 with 10 being the highest or fastest, Whey would be a 10. Casein would come in with a meager rating of 2. But, here is the kicker. That is not a bad thing! This, too, is a good thing. Casein dramatically slows the rate of protein breakdown. Remember, Muscle growth is dependant on the balance of protein synthesis and breakdown. So as we can see here, relying on one or the other, and debating which is superior is futile in the hopes to gain the most benefits from them. To tip the scale in your favor, you need to increase protein synthesis and slow down muscle breakdown. You would be a fool to write one off.

I know what you are thinking, “Why not just mix them together and get the best of both worlds?” Well, I am one step ahead of you. Casein has a unique property, in that is coagulates in the stomach (12). This causes other proteins to be digested and absorbed much more slowly. Have you ever tried to run through a vat of tar? It isn’t easy by any means. You would be moving very slowly. Casein does the same thing to whey, and other proteins for that matter. Think of it as a sort of binding gel. This simple little fact would nullify the biggest and most important attribute of whey. That is its ability to flood your system quickly with amino acid and stimulate protein synthesis.

Now before you ask, let me stop you. I already know what you are thinking. Perhaps it would be best to just slam whey protein drinks all day to keep your system swimming in amino acids, right? Wrong! It may seem counter intuitive, but it would not keep protein synthesis rates up. (2) Just having constantly high levels of amino acids or merely having a positive protein balance doesn’t stimulate protein synthesis (2, 5, 11) and doesn’t lead to increases in muscle mass. (18) Then what does, you ask? All evidence point to the same thing time and time again. It is the acute and large increase in the amount of amino acids in the blood that causes protein synthesis rates to increase (2, 5, 11, 20,15, 13). If you were to tap a vein with an IV to crank blood levels of amino acids up and keep them there, we would see a dramatic increase in protein synthesis as well as a decrease in protein breakdown (11, 2). However, right around two hours, synthesis rates will level off and return to normal despite the abnormally high levels of amino acids (2). What is even more interesting is that even if amino acid levels are already very high and protein synthesis is dropping, I can consume more amino acids and further stimulate an increase in synthesis rates (11).

So here is the take how message. It is not about just shoveling down 4,000 calories7 or X-amount of protein to keep your blood saturated with amino acids at all times. It is the about presenting your body with sudden change and increase of amino acids that stimulates protein synthesis rates (2, 5, 11, 20, 15, 13, 9). This is why it is important to understand the differences between the various types of protein supplements. When products start totting how much of a certain amino acid they have added or that they have a better amino acid profile, just skip it. It doesn’t matter (5). The amino acid profile becomes important when you are comparing different protein sources. And since both casein and whey are derived from milk, they have essentially the same amino acid profile. You should be concerned with the main source of protein so that you know what that product will do for you. Will it stimulate protein synthesis? Or will it slow protein breakdown?

Make no mistake about it, high protein diet are a requirement for packing on high quality muscle mass (1,9,13,15,16,19). But you need to find that middle ground. As we have covered, if you consume so much that you have chronically high levels of amino acids in your blood, much of the protein you consume will go straight down the toilet. Literally (1,2, 5,11,17)! But don’t let people sell you on the myth that your body can only handle so many grams of protein at one time. Firstly, this is a very vague statement. What is meant by “Handle” or “At one time”? About 50% of what you consume is incorporated in to muscle tissue one way or another. 20% is incorporated into other body proteins and the remaining is oxidized (11, 5, 1). A large majority of the 30% is a class of amino acids called Non-Essential Amino Acids (17). And this breakdown of metabolic fates is ay just about any protein intake at any “one time”. On the other hand, if you play it too safe, you will short circuit the muscle building mechanisms and the balance will shift towards muscle breakdown (4,11, 18, 16, 19). So the next time that someone tells you that they won’t be happy until they can walk around with an IV drip of amino acids tapped into their arm, you can tell them they are just wasting their time. Not only that, but you will understand why!

Alright, so we now have all of this information swimming around in our heads. What do we do with it?

Let’s put it together into a plan. We know that wee need to increase protein synthesis and reduce protein breakdown. We know that whey is the most effective product to stimulate protein synthesis, and we know that casein is the most effective product to reduce protein breakdown. We can’t use them together because casein will nullify whey’s primary mode of action. However, we have one more weapon in the arsenal that we can use. And that is our good friend, food. In general, whole food proteins are digested very slowly. That means they will cause a mild and constant stream of amino acids into the blood, much like casein. However, most whole foods do not coagulate in the stomach and do not slow the digestion of other proteins. So the first step in the plan is to forget what you think you know about supplement “Timing”. It is ok to consume whey protein at times during the day other than before or after a work out. And honestly, you should.

Step #1: Consume a whey protein drink shortly after a whole food meal.

By doing so, you will have created an environment very conductive to muscle growth. By consuming that whole food meal you will have suppressed the rate of muscle breakdown. Firstly, by starting a slow cascade of amino acids through your system. Secondly, provided your meal had some kind of carbohydrates, you will have stimulated the release of insulin which in it self can slow the rate of muscle breakdown (11,5,3, 8, 14). Insulin is also the hormone that governs protein synthesis rate. By elevating the release of insulin before the consumption of a whey protein drink, you have effectively set the stage for a serious anabolic reaction (14, 10, 11).

There is a slight delay from the time you digest carbohydrates and the time that insulin levels peak. Because of the fact that whey is absorbed so quickly, it is possible that the peaks between amino acids and insulin with not coincide resulting in a less than optimal response (11, 14). Once the whey protein has been completely assimilated, amino acid levels will drop. However, they will not return to normal, because the “Amino Acid Cascade” that you stared with the whole food meal is still streaming. It’s a beautiful sight, isn’t it? This little step has effectively stimulated protein synthesis as well as slowing protein breakdown.

Step #2: Consume casein based meal with in the next 3 hours.

That means before three hours has elapsed. Two hours would be an even safer bet. We want the levels of amino acids in our blood to drop a bit so we can create a dramatic increase again. The degree of protein synthesis is directly related to the degree of change in the levels of amino acids. By consuming a casein based meal here we will allow for that drop while keeping amino acid levels above normal. This keeps the rate of protein breakdown to a minimum. Do you feel the scales tipping yet?

Step #3 Repeat! That’s all there is to it.

Alternate between a whole food meal with a whey protein chaser, and follow that up with a casein based meal. Now I know this sounds expensive so you can modify it. You may want to reduce the size of the whey protein drink. But remember, the degree of protein synthesis is dependant on the degree of the increase in the levels of amino acids in the blood (2, 5, 11, 20,15, 13). So take caution when you are feeling cheap. It would not make sense to cut your servings and not have a very good response from it. You could also have just a whole food meal instead of a casein based one. You would essentially get the same effect. However, many meal replacement products on the market today have a far better nutritional profile than anyone of us could every pull off in the kitchen. I highly recommend two a day, making sure to have one just prior to bed.

Well there you have it, a three pronged attack. Precision Protein Supplementation. You know have the tools and knowledge to strategically create an environment that is highly conductive to not only increasing lean muscle mass, but preserving it as well. You will be surprised how effective this little strategy is during times of low calorie dieting. So, in summary, casein is a “slow” protein that is classified as anti-catabolic. That means that it prevent excessive protein breakdown. Whey protein is a “fast” protein that is classified as anabolic. Meaning that is stimulates protein synthesis, but does not inhibit catabolism (5, 12, 2). We can’t do both at the same time, but we can mimic the effect by manipulating our dietary intake. And finally, it is the rapid increase of amino acids that results in increases in protein synthesis.

Hopefully I have shed some light on the subject. There is no “Best” type of protein, only a “Best” approach or mix. Don’t let anyone tell you anything different. If they are convinced that there is a best, they are only joking themselves. Just smile, nod and realize that you are bigger than that guy!




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