Dr. Luc (Luke) van Loon

We'll talk about the 100 grams later on probably.

But so in the next four to six hours after a meal, 20 grams of protein maximizes muscle protein synthesis.

Now, if you do that in older people and you give them the same 20 grams of protein, they show a lesser stimulation of muscle protein synthesis and they do not reach that same level and certainly not the maximum level.

So that's what they now call anabolic resistance.

We see that the same amount of protein does not lead to the same increase in muscle protein synthesis that you see in young people.

That is now defined.

I mean, Mike Rennie's group was the first to define that as anabolic resistance.

But the question is, is what is causing anabolic resistance?

Is that because of the age?

But of course, if you compare young and older groups, it's not only about age.

If you compare a young and an older person, it's the age, it's the lifestyle, it's the habitual food intake, habitual protein intake.

It's the code, the medication, the comorbidities that they have.

So you're comparing a lot more.

Now, one of the strongest things that increases the sensitivity to food intake is physical activity.

Now, if you give an older person an exercise session before food intake, their response is almost completely normal.

So much of the responsiveness, the anabolic resistance can be overcome by physical activity.

So my question is, to what extent is anabolic resistance, not for the greatest amount, simply secondary to a lower physical activity level?

If you would actually modulate your protein requirements towards the tissues that require the protein, then it would be better to basically base it on fat-free mass.

because, of course, a lot of the fat mass is not that metabolically active.

Most of it is a fat depot, so turnover of protein is relatively small compared to the organs and the muscle.