Dr. Luc (Luke) van Loon

Somewhere people have actually noticed that or experienced that.

I would prefer the product where the protein actually is in, so not even the isolate or the concentrate.

But then if you're using a supplement and you want to take the pure protein, then you can take the isolate or the concentrate.

The isolate is only the protein, the concentrate is basically the concentrated protein, so it still has other stuff, like for milk protein concentrate, it still has lactose in it and still has some other stuff, some fat in there.

So, yeah, is one better than the other?

No, it depends on what you're aiming for, what your nutrient targets are, basically.

Yeah, then you would go for an isolate, of course.

Yeah, so if you ingest 20 grams of protein, you see a strong, robust increase in muscle protein synthesis that peaks around three hours after a meal and then it wears off in about five, six hours.

Now, one of the factors in that response is leucine.

The postprandial increase in circulating leucine sets off an anabolic pathway in the muscle and is responsible for that stimulation of muscle protein synthesis.

20 grams for whey protein, that will be about 2 to 3 grams to 2.5 grams of leucine.

So you can also give that as free leucine or as the branch chain amino acids, and we've done that as well.

We also see that very strong increase in muscle protein since the first two hours, but then it wears off much more rapidly.

So you need the leucine to stimulate the process, but then you also need a sufficient supply of all the amino acids to allow muscle protein synthesis to continue for a while.

So it's a double whammy.

It's both the signaling and supplying enough of the building blocks.

And that's the leucine threshold.

Now, exercise, like we said before, exercise makes the muscle more sensitive to the anabolic properties of protein feeding.

So it reduces your leucine threshold.

So with a lesser increase in leucine, you would actually get a greater muscle protein synthesis.