Dietary protein: amount needed, ideal timing, quality, and more | Don Layman, Ph.D.

The most critical meal of the day is the first meal of the day. When you have had an overnight fast, your protein synthesis is down, and that mTOR signaling molecule is down-regulated; it's inhibited. And until you have enough leucine—around 3 grams, which translates to about 30 grams of protein for most people—until you have a meal that has 30 or more grams of protein, your muscle stays catabolic. So, you're continually breaking down protein.

What's its bioavailability? How well do we digest it and absorb it? With animal proteins... the digestion/absorption is pretty close to 100. It's usually 95% or higher for all animal proteins ... In a plant, the protein is there for the purpose of the plant. And so a lot of it is attached to fibers, to structures. ... When you start to isolate that, to just eat it in a raw form, it may only be 60-70 % available, because we can't digest the fiber.

The more trained you get, the less you're gonna see a post-exercise effect. So, if you're beginning training (near the first 4 weeks), post-exercise protein probably makes sense. If you're well-trained, you've basically been training the same way and you've been doing it for 6 months, I don't see any effect difference between having protein within 2 hours after exercise versus just having your 3 or 4 meals per day. You won't see any difference in either mass or strength.

Protein we should think of as a vitamin pill. We don't have a daily requirement for a vitamin pill; we have a requirement for 12 vitamins inside the pill. We don't actually have a daily requirement for protein; we have a requirement for 9 or 20 amino acids inside of it.

You can take all those amino acids before, but it's not going to prevent you from becoming catabolic during exercise, because, again, exhaustive exercise is a catabolic activity. So, you are going to be breaking down muscle no matter how many amino acids are on board while lifting. It's more important after the lift that you have a good meal.

That's where people fall apart is that we think about vitamin C, and we know there's a minimum RDA to prevent scurvy, but people will take 5 or 10 times that during COVID for immune response, but we resist thinking that way about amino acids, and it's exactly the same.

We burn around 100 calories per hour. That would be 2400 calories per day. So, 100 calories per hour in a 2-hour period, you're only burning 200 calories. So, everything else has to be stored. Average American meal is 400 to 1,000 calories—that means you have to store all of that.

One of my pet peeves in nutrition... is people refer to protein as a percentage of calories. Protein is not a percentage of calories; protein's an absolute number ... If your calories go down, say you're now a 75-year-old woman and calories per day is now 1200 calories, you still have a 100 gram per day protein requirement.

Doug and I ran a study... where we took 90 grams of protein and looked at it distributed as 3 meals per day, 30/30/30 vs. 10/20/60, and we found that with the same amount of protein, the same overall diet, you would have higher net protein synthesis with the distribution to breakfast.

When we look at our patients and evaluate them from a nutritional standpoint, almost without exception, we come to the conclusion that they are not getting enough amino acids based on how much protein they're consuming.

We're starting to see New York City taking animal proteins out of school lunch. I mean, what is that really going to do? We're conducting a public health experiment without actually having any knowledge of that.

You'll hear trainers say, 'Well, you can't use more than 30 grams [of protein] at a meal; you won't digest it,' or whatever. That's not true. You'll digest and absorb 100 grams of protein at a meal. But muscle, in particular, only has a window of around 25 to 60, depending on protein quality, where it can use it. The liver will use all of it; it doesn't matter.

I very early developed the philosophy that nutrition was really about two tissues: the brain and skeletal muscle. If those two tissues were healthy, you were going to live a pretty good life.

Muscle is the largest sink for glucose. 75-80% of our glucose storage capacity exists within skeletal muscle.

Muscle really serves two functions. The obvious one is mobility. Most people get to the age of 65. Beyond that, most people actually die from some form of immobility—falls, breaking something, hospitalization. So, functional mobility is critical.

We need about 3.4 grams of lysine per day. We need probably a little less than 1 gram of methionine.

Excess glucose is toxic. If the blood level is high, you'll damage basically every tissue from your eyes to your toes. And so, you have to dispose of the glucose.

Reducing the number of meals per day actually is thermagenically advantageous. You actually waste more calories.

We consume carbohydrates virtually exclusively for their energy content, fat mostly for its energy content... But really, you don't want to be consuming protein for energy.

Now we've got an issue of mTOR and whether it needs to cycle on and off. And not only does leucine turn it on, but so does insulin. Probably the worst case scenario... would be people who eat a lot of small carbohydrate meals that continuously activate mTOR.

There's a lot of data now that muscle can handle protein meals for an optimum anabolic response between about 25 and maybe 60 grams.

In the same period of time, an older adult in bed rest will lose four times as much muscle as a younger adult.