Is it necessary to take «fast» and «slow» protein, or is it a scam?

Author: Timko Ilya - master of the whole project and fitness trainer.
2015-10-03

This is a scam.

Of course, by “fast” protein, I mean whey protein, and by “slow,” I mean casein (micellar casein or calcium caseinate). The idea to write this article arose because I often receive stories like: “I came to buy protein in a store, and they told me that I need to buy whey protein after training and casein at night.” In other words, sports nutrition sellers often convince people that they need two types of protein. But is this really the case?

1. Difference in Amino Acid Composition

I compared whey and casein in terms of amino acid composition. The set of amino acids is completely identical. The difference in the quantitative content of various amino acids is within +/- 10%-20%. That is, some amino acids are slightly more abundant in casein, while others are in whey. Overall, it can be said that the differences in amino acid composition are insignificant. This makes sense since both of these proteins are derived from milk.

For example, casein has slightly less BCAAs and alanine. But slightly more phenylalanine and glutamine.

2. Difference in Absorption Rate

This is the main argument that sellers and manufacturers emphasize. Indeed, whey protein (especially hydrolysate) starts to be absorbed almost immediately after consumption. And it is completely absorbed within a couple of hours.

Casein also begins to be absorbed almost immediately. However, its absorption rate is about twice as slow. In other words, it will completely absorb in approximately 4-5 hours.

Is there any significance to this for our body and our muscles? I studied physiology and biochemistry for 5 years at university and can say that there is NO difference for the body. Whether a protein portion is absorbed in 2 hours or 4 hours – it doesn’t matter to the body. As long as it gets absorbed.

But sellers say, “After training, you need to give your muscles protein as quickly as possible. Otherwise, they will start to break down!” Yes, if you don’t provide your muscles with protein for a day or more, they will indeed start to break down. But when it comes to a difference of a couple of hours – nothing will happen to your muscles. Especially since casein also starts absorbing immediately, just more slowly.

Sellers also say, “Eat casein at night. It will nourish your muscles all night. This will prevent them from breaking down.” So, if you eat a balanced diet, your body has enough amino acids to nourish your muscles all night, even if you didn’t consume casein at night. And if your overall diet is lacking in protein, then casein at night won’t save you.

This creates a situation where it seems the producers and sellers are not lying to you. They just don’t tell the whole truth, emphasizing the difference between whey and casein and turning this minor difference into a decisive one.

3. Difference in Price

Many have probably noticed that casein is about 30% - 50% more expensive than whey protein. This is a significant difference. I don’t know why this is the case. I only know that most of the protein in milk is actually casein, not whey.

So, it turns out that casein is produced in larger quantities and needs to be sold somehow. But who is going to buy it if everyone knows that it won’t provide any benefits, just extra financial expense? That's why manufacturers are touting at every step that you must buy casein along with whey protein.

Conclusions

Don't misinterpret my words and write in the comments that I am criticizing casein. I regard casein as well as whey protein. I just don't believe that casein has any unique effects or advantages. I use both casein and whey protein equally and don't categorize them as post-workout protein and night protein.

It just so happened that after curdling milk, whey is produced, from which whey protein and cottage cheese – that is casein – are made. Both of these milk derivatives are used to produce protein. And both of these proteins need to be sold. That’s why the sports nutrition industry works so hard to promote them.

Personally, I like casein only because it has a pleasant cottage cheese flavor even without flavor additives. If I buy casein, I drink it in the morning, at night, and after training. And if I have whey protein, I drink it the same way. Because I know that the difference in absorption by a couple of hours won’t make any difference. And if there is no difference, why pay more? Good luck!