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Why Whey Protein?

With Paul Kriegler, RD, CPT

person holding a protein shake and Paul's headshot

Season 8, Episode 4 | April 2, 2024

Whey is considered one of the best sources of protein — and because adequate protein is challenging for many people to consume from food alone, they often turn to this protein powder to supplement their needs. Paul Kriegler, RD, CPT, explains what whey protein is, its health and fitness benefits, the difference between whey concentrate and whey isolate, and how to choose a quality whey protein supplement.

Paul Kriegler, RD, CPT, is the director of nutritional product development at Life Time.

In this episode, Kriegler offers some key insights and information about whey protein, including the following:

  • Whey protein is a byproduct of cheesemaking. When milk from cows is processed, typically into cheese, the liquid that comes off the curd is whey protein. Over time, producers have figured out how to isolate that liquid, dry it, spray dry it into a powder, and process it to make a supplement.
  • The further you get from milk to the end product determines the type of whey protein product you get. The result of minimal processing is whey concentrate, which is usually 70 to 80 percent protein by weight. More processing results in further isolation of the protein; this is whey isolate, which is upward of 90 percent protein by weight.
  • If you can tolerate the few grams of lactose that’s in whey concentrate and are OK with the accompanying fat and carbohydrates that make up the remaining 20 to 30 percent of the product, Kriegler believes whey concentrate is the best all-around protein. However, if you can’t tolerate lactose and/or want fewer fat and carbohydrates, then whey isolate is a standout option.
  • Protein, especially whey protein, is an incredible source of essential amino acids, according to Kriegler. Your body needs essential amino acids to build every structure it has, including your muscles, skin, hair, and bones. Protein is also critical for maintaining the integrity of cells, supporting the creation of neurotransmitters, and balancing hormones.
  • Protein quality matters. Life Time’s whey concentrate is sourced from 100 percent grass-fed cows in New Zealand. For whey isolate, because so much is stripped out in processing, sourcing from grass-fed cows isn’t as important; domestic cattle that are not treated with hormones are the source for Life Time’s whey isolate. All products are free of added sugars and artificial sweeteners and go through strict quality testing.

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Transcript: Why Whey Protein?

Season 8, Episode 4  | April 2, 2024


Welcome to Life Time Talks, the podcast that’s aimed at helping you achieve your health, fitness, and life goals. I’m Jamie Martin, editor-in-chief of Experience Life, Life Time’s whole life health and fitness magazine. And I’m David Freeman, director of Alpha, one of Life Time’s signature group training programs.

We’re all in different places along our health and fitness journey, but no matter what we’re working toward, there are some essential things we can do to keep moving in the direction of a healthy purpose-driven life. In each episode, we break down various elements of healthy living, including fitness and nutrition, mindset and community, and health issues. We’ll also share real, inspiring stories of transformation. And we’ll be talking to experts from Life Time and beyond who share their insights and knowledge so you’ll have the tools and information you need to take charge of your next steps. Here we go.


Hey everyone, welcome back to another episode of Life Time Talks. We are talking about one of those supplements that you probably hear about a lot and maybe have some few questions about, whey protein. And with us, we have one of our go-to nutritionists from Life Time. David, why don’t you intro one of our favorite guests?

Paul Kriegler is back, ladies and gentlemen. If you don’t know, he’s a registered dietitian, personal trainer, and he serves as a director for nutritional product development for Life Time. Paul, welcome back. How you feeling?

I’m doing great, David. Thanks for having me back.

Yeah, yeah. It’s great to have you back. So it’s a question that’s been weighing on my mind here, Paul. And we all need to know what exactly is whey protein.

I see what you did there. I like it. Whey protein is a byproduct. It’s from the dairy industry. It’s a byproduct of cheese making. Even as recently as a couple of decades ago, it was thought to be a waste product. So when they’re converting milk, processing milk from cows typically into cheese, the liquid that comes off the curd is whey protein. So some genius figured out how to isolate that liquid, dry it, spray dry it into a powder, and you know process it in a couple different methods and create a supplement. Something that’s really incredible at, you know, at boosting protein content of foods and helping with all kinds of health benefits.

We’re going to get to those. We’re going to get to those. You alluded to like the kind of different types of whey protein. So let’s talk a little bit about that for a moment. I know there’s isolate, there’s concentrate and like, are there more? Can you just break those down for us and what the differences are?

Yeah, absolutely. So if you’re familiar with milk, milk has protein in it. It’s mostly water, has some protein in it. It also has some carbohydrates in it, mainly in the form of lactose, which is one glucose molecule and one galactose molecule bonded together. And then there is some fat in milk as well. So when you process milk into cheese and the liquid separates from the curd, which is mostly made of a different type of protein found in milk called casein. So casein is the primary protein that gets made into cheese. Whey is kind of the excess that’s more liquid. The further you take it from milk to the end product determines how much or what type of whey product you’re getting out of that whey liquid. If you don’t process it very much, you get what’s called a whey concentrate. And that’s usually between 70 to 80% by weight protein. The rest of that weight is leftover carbohydrates and leftover fats that are in the material. If you put that material through even more processing, typically a cross flow micro filtration, which is just fancy use of different gradients and filters, you can further concentrate or isolate the protein and raise the protein content of the final product upwards of 90 to 92, 93% by weight. So when you see whey concentrate, it’s technically less processed, less filtered, because it still has more lactose in it and more fat content left in it. Whereas if you see whey isolate, it’s gone through further processing to raise the protein content and decrease the fat and the carbohydrate content.

Paul, you said casein in there, and I know a lot of individuals that are trying to get their protein in throughout the day. I’ve heard like casein is what you can take prior to going to bed. If it’s not casein, if it is a form of whey, is that the one you would recommend? And if so, why?

That’s a good question. There’s actually, so with the milk proteins, the major milk proteins, in terms of the health benefits, so whey protein or proteins from milk, I should say, are extremely good at stimulating muscle protein synthesis. So the repair and building of lean muscle tissue in humans. All three of them are great at it. So when I say three, I mean casein, whey concentrate, and whey isolate. There’s very little difference between what the end result is from consuming those protein types. The difference just comes in what do you want it to do in the intermediate time, from the time you consume it to the time you get the result? Casein takes a long time to digest. It actually, you know, if you consume it in raw milk form or in cheese form, it sits in your stomach for quite a while, the casein fraction does, and it releases its amino acids over an extended period of time. So that’s why some people are drawn to it. You could argue it gives you a little bit more satiety benefit, so it helps manage appetite maybe a little bit longer and it’s slower to digest. So you’ll have kind of a longer rise in the amount of amino acids that enter your bloodstream from that protein source. Whey concentrate is pretty rapidly absorbed compared to casein. It’s very simple to digest and absorb. I would consider it an equally good source of all the essential and branched-chain amino acids that are particularly good at stimulating muscle protein synthesis. The downside of whey protein concentrate is you have to consume more calories, more sugar, and more fat to get the protein you’re after. So in that regard, it’s a good general-use protein because what you can also get if it’s a quality source of milk that that weight concentrate is from, like a grass-fed milk, and it’s processed pretty minimally to get to that 80% by weight protein concentration. You’re also left with a couple of immune globulin proteins that aren’t filtered out that can help your immune system. There’s also some other protein fractions that are real minor components of milk protein, but they help with gut function. And we know that gut function and immune function are inextricably linked together. So if you can tolerate the few grams of lactose that is in a weight concentrate, and you have the budget in your calories to have a few grams of fat with your protein, I think it’s the best all around protein is weight concentrate. However, not a lot of people deal with lactose very well, and not everyone wants to consume extra carbs and extra fat when they’re really after just getting extra protein. So that’s where whey isolate really stands out as a star to those types of people. If they’re just looking for protein to add to their diet, that’s super easy to digest and absorb. And it can basically infuse into their bloodstream really quickly. So like after a really hard workout, your muscles are damaged, you need repair materials there quickly. Whey isolate is a rock star in that regard.

If I heard you correctly, then you said the casein is a slower digested protein. But then you have the protein synthesis that now can take place probably at night when you are asleep. Is that the benefit of taking that one at night?

That’s the common thought. It really doesn’t matter which one you take at night. There’s, when you look at head to head, people taking casein, whey concentrate or whey isolate, if they’re taking the same amount, they’re going to get to the same outcome.

So Paul, you mentioned grass-fed and I want to talk a little bit about why that matters in terms of the way that you might select.

Sure. Grass-fed, so grass-fed matters the most for, I would say the casein fraction of the milk and the whey concentrate level of whey protein. So when an animal is grass-fed or grazing on pasture, their natural diet of grass is, they tend to have better overall health. Their milk production tends to go up a little bit. Their resilience in infections and that sort of thing is just a little bit better. They will end up producing some of the fat in the milk, will be a higher percentage of omega-3 fats. Also a higher percentage of conjugated linoleic acid, which is a metabolically beneficial type of fat.

And some people would argue like the flavor is unmatched. You know, the lactoferrin and the immune globulin proteins tend to be higher concentrations in grass-fed animals versus grain-fed or feedlot animals. So it, it’s really a consumer’s choice at this point. But there are some minute and meaningful health benefits by choosing a kind of a naturally raised, pasture-raised, grass-fed cow for that source of protein.

Hey, Paul, I get this question all the time and people gotta hear it from you because they don’t believe it when I say it. So I wanna know, how do we determine how much protein one needs? And let me frame it up a little bit differently. So the amount of protein that one will need, and I can use myself for example to kind of help out with the math at least. And I know it could be a little bit relative or subjective to each individual, but the amount of whey protein or amount of protein that individuals should consume. I weigh roughly around 220 pounds. Let’s say of my 220 pounds, 190 ish or so of it is lean body mass. My ideal body weight, Paul, I want to be around 215. So how much protein should I be taking in knowing those numbers?

Yeah, there’s two targets that people are maybe familiar with. One of them, one target is, the amount you need to just not get sick. To not suffer from protein deficiency syndromes. That’s called the RDA. That doesn’t apply to you, David, because you’re not sedentary. So that target is completely irrelevant to you. By the way, if you said you’re 220 pounds, you’re 100 kilos, .8 grams per kilo is the RDA. You’d be 80 grams of protein per day.

The quick and dirty answer to your question, double that. And that’s your minimum. That’s your minimum. That’s David’s dietary allowance. So, the DDA.

I like it.

You’re active, you’re exercising, you have a higher proportion of lean body mass. Your protein needs and protein turnover rate are so much higher than somebody who’s sedentary and just lying in bed. That your raw material needs to keep that protein mass built. And, recovered and healthy is just so much greater. It’s at least double. In fact, we start people at about twice the RDA and it usually works out to like estimating one gram per pound of fat free body mass per day. So if you know your body comp in terms of like how much fat weight do you carry versus not fat weight, it’s a pretty easy mark to estimate for people. You know, simply step on the InBody figure out what your body fat mass is and subtract that from your total weight and then that you know use that as your estimator mark for your protein needs if you’re an active individual There’s some super interesting protein overfeeding studies that have been done taking people, you know, typically they’re young males who are working out so like you David and changing nothing about their diet other than adding protein and up to four or five times the RDA. And the outcomes of what happens when they observe these participants over like eight or 12 or 16 weeks is they usually don’t gain any body fat and they usually gain strength better than someone who’s just getting like an adequate amount of protein. So the amount of calories they’re adding is tremendously high above their baseline. It’s on top of their diet. And they have to use whey protein to do this because it’s so easy to drink and cram down a ton of protein. But the outcomes are like, well, mathematically they should have gained, you know, several pounds of fat in that time frame, but they didn’t. So the protein overfeeding studies are really compelling to look at. Like, very few bad things can happen by overfeeding someone protein unless they have known kidney disease. So that’s why when I say like your recommendation because you’re exercising regularly and you have a lot of lean body mass is it’s about double the RDA and that’s your new minimum. Like you could probably go up from there and what’s going to happen is you might even have further benefits. There was a more recent study on protein after exercise showing that 100 grams of protein supplemented after exercise outperformed, from a muscle protein synthesis standpoint, 20 grams of protein. And we know 20 grams of protein at one dose is like the minimum to kind of flip the switch from your body’s breaking down tissue to now it’s capable of rebuilding tissue or repairing tissue. And that one’s interesting because it was previously thought there was an upper limit of how much protein you could consume at one time and still benefit from it. That study kind of blew the doors off of that line of thinking.

Paul, I think we need a written piece about this. I think we need a written piece about this overfeeding thing. I mean, I’m just just a hint. I’m giving you a little like here. I’ve got an assignment for you. Let’s talk a little bit about the health benefits of protein. You mentioned muscle synthesis, you know, rebuilding. You talked a little bit about gut health. Like what are the benefits of you know, of taking whey protein, why would someone want to take it?

Yeah, the main reason is protein is especially whey protein is an incredible source of essential amino acids. So protein is long chains of amino acids, your body digests those proteins down into shorter and shorter chains of amino acids until they’re individual amino acids. And that’s when they cross into the bloodstream. Essential amino acids are, there are about nine of the 21 or 20, depending on the source you look at, there’s 20 to 22 amino acids humans need. Nine of them we have to eat in our diet or supplement because we can’t make them from other amino acids. Whey protein is an incredible source of those amino acids, those essential amino acids. And that’s what your body needs to build every single structure it has. So muscles, skin, hair, bones. Bones are actually a, you know, a rigid protein scaffolding with minerals stuck in it. Blood cells, organs, you know, everything, we’re built of protein swimming in water. If you think of it that way, protein, minerals and water mostly. We happen to have fat too. But protein is critical for maintaining all those structures, maintaining integrity of our cells.

Other things that are made from protein that are pretty critical to our health are neurotransmitters, which are what helps send signals through our nervous system and in our brain. Hormones have a protein component. Receptors on cells where those hormones might attach or act are built of proteins. So, quite literally, we are made of protein and we turn over all of our proteins in our body a few times a year.

So, if we don’t eat the protein, our body will find it somewhere else on the body, break it down and steal it. That’s how critical it is. So, when you talk about immune benefits, if you’re low on protein, you might know it because you’re hungrier than normal. You don’t recover as quickly as you probably should. Like, you can’t repair a damaged muscle tissue very quickly. Little wounds like cuts and scrapes don’t heal very quickly. And, yeah, there’s a whole host of things that can go wrong when you don’t have enough protein. Can’t emphasize enough.

And I know that’s one of our kind of nutrition go-to recommendations is get the protein. It’s so, so essential.

Yeah, yeah.

Paul. I know we’re on a shorter mini episode here. So, is there anything else people should consider or know about way that we didn’t touch on?

Yes. You know, protein quality matters a lot. So, at Life Time, like, we choose for our concentrate products, they’re made from 100% grass-fed cows milk from New Zealand. That’s what we use in our whey concentrate products. So that’s our whey concentrate, our grass-fed whey, and our grass-fed whey all-in-one. When you strip out all the lactose and all the fats and you end up with an isolate protein, it doesn’t necessarily matter as much that it came from a grass-fed cow, because you are stripping out pretty much all the benefits other than the amino acids. But we choose domestic, non-GMO, non-hormone treated cattle for the source of the milk for our whey isolate protein. And what you end up with is a whey isolate that’s north of 90% protein by weight. So there’s very little, if anything else — in fact, we know from laboratory analysis, our like 20 gram scoop of our whey isolate protein has less than half a gram of lactose left in it and no fat. So it’s literally just protein. And really looking to the kind of quality sources like that.

So if you’re recommending someone’s going out to buy a whey protein, what do they want to look for on a label? I mean, we know what our standards are, but I mean, what’s something to watch out for?

You don’t want to see proteins that have added sugars. So that’s pretty clear on nutrition labels and supplement labels now if it has sugars added to it. I always encourage people to stay away from that. Artificial sweeteners have no place in a protein product, in my opinion. So look for something that’s sweetened with stevia or monk fruit instead of sucralose, ACE-K, aspartame. So you want to do natural flavors, natural sweeteners, and then ideally third party tested. So all of our proteins have gone through testing with our manufacturer and outside labs, as well as third party independently verified through NSF.

A lot of details. We squeezed a lot into like 20 some minutes here. But Paul, so we have at Life Time, I’m just going to clarify, we have a whey concentrate, a whey isolate, we have an all-in-one. And they can find that at if people are interested in that. Where can they find you? Where can people hear more from you?

Well, I’ve got a few articles and podcasts on My Instagram, which is not very active, is @_cafepk_. And then you, I guess, go check out the other podcast episodes. We go deep in protein on one. We go deep on supplements in another. We go deep on artificial sweeteners on another. I think they’ll find some interesting content that we’ve all chatted about before.

Well, we love having you back and that’s why we can kind of get into the science of it, the why of it and all those pieces. So, Paul, thank you as always for coming on.

Thanks for having me.

Thanks, Paul.


Thanks for joining us for this episode. As always, we’d love to hear your thoughts on our conversation today and how you approach this aspect of healthy living in your own life. What works for you? Where do you run into challenges? Where do you need help? And if you have topics for future episodes, you can share those with us too. Email us at or reach out to us on Instagram at, @jamiemartinel and @freezy30 and use the #LifeTimeTalks.

You can also learn more about the podcast at And if you’re enjoying Life Time Talks, please subscribe on Apple Podcasts, Spotify, Google Podcasts, or wherever you listen to podcasts. If you like what you’re hearing, we invite you to rate and review the podcast and share it on your social channels too. Thanks for listening. We’ll talk to you next time on Life Time Talks. Life Time Talks is a production of Life Time Healthy Way of Life.

It is produced by Molly Kopischke and Sarah Ellingsworth with audio engineering by Peter Perkins, video production and editing by Kevin Dixon, sound and video consulting by Cory Larson, and support from George Norman and the rest of the team at Life Time Motion. A big thank you to everyone who helps create each episode and provides feedback.


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The information in this podcast is intended to provide broad understanding and knowledge of healthcare topics. This information is for educational purposes only and should not be considered complete and should not be used in place of advice from your physician or healthcare provider. We recommend you consult your physician or healthcare professional before beginning or altering your personal exercise, diet or supplementation program.

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