Whether it's electrodes in your bathroom scale or a sci-fi pod, accurate tools are needed to track progress. In this episode, Dr. Dale Wagner explains why understanding body composition is important, and he talks about how he makes sure that measurement tools are accurate.
Dale Wagner: [00:00:01]
Weight is just a number, it's just a body, it's not really quality. Body composition, most people look at it as simply the amount of fat mass that you have relative to your total mass.
Wyatt Voice Over: [00:00:15]
If you're trying to track progress or make health decisions, understanding how much fat or muscle is in your body can be really helpful. And Dale Wagner is making sure that we understand the tools that help us do that.
Dale Wagner: [00:00:27]
Most of my research and body composition is looking at methodologies. So, you know, how do we measure that? How do we measure body fat? You may have heard of skinful callipers, right?
Wyatt Voice Over: [00:00:40]
Ok, you'll learn about skinful callipers in a minute, but you'll also hear about a lot of tools that people can use to understand a person's body composition. You'll hear why it's important for people to have access to that information and you'll hear how different tools will work better for different people. We'll also talk about how health outcomes are affected by where fat is stored on the body. My name is Wyatt Traughber, and you could be wrapping some kitchen twine around some turkey legs...But you are listening to this instead, a podcast from the Office of Research at Utah State University. You know, I think we throw the word obesity around a lot, and I'm not even sure I know what it means. So I asked Dale.
Dale Wagner: [00:01:25]
Yeah, good question. So a lot of times, like a physician or many times in clinical settings, they'll use something called body mass index. You may have heard of that before. And so the World Health Organization has standards for body mass index. And so a clinical definition for obesity would be a body mass index of 30 or greater. But the problem with body mass index is it's only really it's kind of a glorified height weight chart, if you want to think of it that way, right. For the average person, it's fine. It will give you a pretty good idea. But it's not really telling you anything about the quality of your weight.And so what I've often said in class, the students, you know, a 40 pound.Forty pounds of fat weighs how much, 40 pounds, 40 pounds of muscle weighs how much? 40 pounds, 40 pounds? Yeah, go to Smith's grocery store, buy a 40 pound sack of potatoes, weighs 40 pounds. Right. So just standing on the scale isn't really telling you about the quality. It's only telling you what quantity. And that's where body composition comes in, where you're actually trying to get a measurement of body fat as opposed to a body mass. You may have heard of skinful callipers, where you just pinch an area of the person's skin and you measure it. That's a very simple technique in terms of it's it's not very costly, but in reality, that's actually a hard technique to master to to get good at pinching the right location and the right amount. It's something that we find that our undergraduate students often have a lot of difficulty and takes quite a bit of practice to get that correct, as opposed to other more sophisticated laboratory methods. Some are so sophisticated, something like dual energy, x ray absorb geometry. It's essentially an x ray scan. Right. So a fancy x ray scan. And based on that x ray scan, we can get a pretty good estimate of not only how much fat you have, but where that fat is located. Right. Is it on your trunk or is it on your limbs? And that has health implications.
Oh, what are the health implications of storing fat in different places?
Dale Wagner: [00:03:48]
Yeah, sure. So we know there's tons of research that documents that if you contain a lot of visceral fat or truncal fat, so fat around your around your gut, that is far worse in terms of health risk as opposed to having the fat distributed. More on more on the limbs. An example uses apple shaped versus pear shaped. You know, if you're an apple shaped version of fat around the middle, that's far worse than being a pear shaped version where your fat might be more on the hips or more on or on the limbs, that kind of thing.
Do we know why or is there just correlations there for like life expectancy?
Dale Wagner: [00:04:32]
Again, there's all kind of correlational research, but there's also physiological reasons as well. The gut there's actually multiple layers of of fat that can be stored there. So if you have someone who's very lean, they're only really going to have that outside layer, that subcutaneous fat.
Dale Wagner: [00:04:53]
But if you have people that have the deep internal fat, that's far more problematic. Why? I'm not entirely sure off the top of my head.
Wyatt Voice Over: [00:05:07]
But OK, so if you want to know why abdominal fat or truncal fat around your waist is worse, after a few minutes scrolling the Internet, I found an article on AARP, dawg, and essentially what they're saying is fat around your waist is worse for you because it's closer to all of your internal organs. That's putting pressure on your internal organs. There's a lot more blood flow there because of your internal organs. And so the hormones and the effects from that fat are going to be worse because they're just closer to where the action is. Is that an oversimplification from me reading stuff off the Internet? Yes. If this brings up questions about your own personal health, you should talk to a medical practitioner. All right. Back to my conversation with Dr. Wagner. So what are some of the misconceptions that people have about that?
Dale Wagner: [00:05:54]
Yeah, actually, fat does many wonderful things for us. Right. And so, I mean, it kind of gets a bad rap, basically. First off, in terms of energy, it's it's a great energy source. It's a very efficient way that the body has to store energy. One gram of fat will give you nine calories worth of energy, whereas one gram of carbohydrates only gives you four calories worth of energy.If that didn't exist, we would have in order to store as much energy as we.As we do, we would probably be as big as a house, right, because carbohydrates and protein aren't just they're not very efficient forms of storage. Basically energy for one, is very important function of fat, but also insulation keeps you warm. And in the cold winters, people that have very little body fat, they shiver a lot in the winter. Right. And then also protection. We don't often think about it, but there is a layer of fat around your brain, around your kidneys, those kinds of things. So if you're in an accident or you get jostled around, that fat is there to protect those organs.
Wyatt Voice Over: [00:07:06]
Ok, so that's important. Let's remember that according to a BMI calculator I'm looking at, I was obese for a few years and there's lots of stuff I don't miss about that time. But I do miss being warm, which is one of the things Dr. Wagner just mentioned. I also miss just being comfortable. I could sit on a wooden chair for hours and I never had a problem sleeping on any of those crappy student housing mattresses. And people will tell you that food won't solve your problems, but warmth in general can sure give you a nice break from them. As I began working on my health, I got one of those bathroom scales that gave me numbers about my body composition that I could track instead of just telling me my weight. So I asked Dale about what's up with my bathroom scale. My scale has little metal electrodes on them or something.
How accurate is that method?
Dale Wagner: [00:07:59]
Yeah, that's called bio electrical impedance. So actually what your scale is doing is sending a small electrical current through your body when you stand on it. Now, the current so small that you can't feel it. You're not getting shocked or anything if that cell doesn't have a lot of water to it. Right. But everything else in your body does have water. So as you probably learned in like elementary school or something, electrical current travels pretty easily through water, right through the electrolytes that are in water. And so when you stand on that scale, that electrical current is, for the most part, traveling pretty easily through you, but it's only being resisted by the fat. So based on the amount of resistance, the computer and your in your scale is saying, OK, well, you have this much resistance to this current, therefore you probably have this much body fat. So let's just another method, one of many that we have that will kind of estimate body fat. Yeah. Is it accurate or not? Good question. For the average person on average, if we look at one hundred people, we would say it does pretty well. But there are individuals that the method does not work so well.
Is that just because they keep their fat in different places thinking like if the current is going in one foot out the other, if like there's a whole lot of my body that that current is missing?
Dale Wagner: [00:09:26]
Yeah, there is an estimation there. That's correct. Right. And so if you have something like like what you're describing would be a foot to foot via where. Yes, the currents going up one leg and sort of down the other. You know, there's probably some information that you had to type in to the to the the scale when you first started it up your age and so forth. And so based on your height, it's saying, OK, well, if your lower limb has this much resistance to it, we're assuming that your upper body is proportional to your lower body. Right. So, for example, if you had a really short torso but really long legs, and that might throw the throw the machine out of whack. And because that that technique by electrical impedance is so dependent on on the water content of the body, you can really mess that up by dehydration or hyper hydration. And so probably when you bought the device, if you read the user's manual, they probably had some specific guidelines in there about, you know, its most accurate if you don't eat two hours beforehand or something like that. Right. Because if you if you slug a leader two liters of water and then stand on the scale, you're going to mess it up. We do community testing in our lab, by the way, maybe about once a week.I'll get someone emailing me, hey, can I come in and get a bodpod test? That's one of the ways that we measure body composition. Looks like a little a kind of a modern way. You may have heard of what's called underwater wing. We have an underwater weighing tank as well. But that's a fairly difficult method where we have to dump the person underwater, have them blow out all their air underwater, which is not a natural thing for people to do. A lot of people get sort of freaked out by the whole experience. And what you're trying to do with underwater weighing is. You're trying to measure how much volume the person takes up. If we know their mass and we know their volume, we can get density and then convert density into percent body fat. The bod pod does the same thing, but instead of water displacement, it's air displacement. So essentially, we know how much air is in the body chamber, so if we put something in there, a certain amount of that air is going to get displaced and essentially that the purpose of the bodpod is to measure your volume and then we get your mask just off of the scale. So masked by volume is those body density. Make another conversion to get from body density to the.
Yeah, yeah, take me into the world of body composition research, what's going on there and what is your piece of it?
Again, my area and body composition researchers are usually looking at methodologies and and seeing how accurate they are and how reliable and valid they are. One of the areas I've been looking at a lot is the last few years is using ultrasound, ultrasound that most people are familiar with be called the modal ultrasound. That's the ultrasound that gives you a little kind of grainy image on a computer screen. But we've been using something called Aimard ultrasound, which, instead of a grainy image, just gives you a graph. So a little peaks and valleys on the screen and one of the key differences there is cost, you know, a nice be ultrasound that you would find in a hospital. That's a thirty thousand dollar piece of machinery where a little aimard ultrasound. Might cost you two thousand dollars. So a huge cost differential, something that a personal trainer might be able to afford and a model versus something, if it's thirty thousand dollars, they're not even going to consider that. We've been taking a look at. Is this low cost mode ultrasound, can we get reasonably accurate measurements from this compared to a more expensive device?Can you? For the most part, yes.
What kind of information is the ultrasound giving you?
Yeah, so the ultrasound, we're kind of looking at that as a way to sort of replace the skinful Culvers. So remember, with the skinful callipers, we're kind of pinching an area of skin and then measuring it. The problem with that is it's it's it's not a true measure. That's what I would call an indirect measurement of subcutaneous fat, because you're really getting a foaled. So it's kind of a double layer of fat, really, that you get with a skinful. Colpeper Right. You're taking a hold of a person's fat and then you have this. It's kind of sandwiched between the skin, whereas an ultrasound, you're getting a direct measurement that ultrasound beam is going directly in and directly out. And we can do that without compressing compressing the tissue as well.
So do you just do that, like behind the hip bone or somewhere where it can bounce off the various sites?
Just like there are various skinful sites? There are various sites for ultrasound as well. And what will happen is there will be a graph. And so what happens is where there's a tissue interface. So, for example, where the fat and muscle come together, that's where the ultrasound changes. And so that's that will give you a peek on a graph, so where the fat muscle comes together, you'll get a peek where the muscle and bone comes together, you get another peek. And so basically, all you have to do is look at the peak and then read the graph in the graph on the x axis of a graph, it will have the depth. Of the ultrasound. So if that peak occurs at, for example, seven millimeters, then we would say here you have seven millimeters of fat in this location. That's so much easier for, say, your personal trainer, so much easier for a personal trainer to look at a graph and look at a peak on a graph than it is to look at a a what we call it B mode ultrasound image, where you have a two dimensional image of the body and you have to figure out, well, where is the skin layer? Where the fat layer, where is the muscle layer. Right. If you have to try to decipher all that. To read a B mode ultrasound image really takes a fairly skilled, you know, like an ultrasound technician.
I mean, this could help personal trainers, but could it help like school nurses or. I remember, like every year in elementary school we get weighed and measured and.
Yeah, sure. Anyone responsible for taking body composition and measurements, whether it's a personal trainer or a school nurse or a strength and conditioning coach, you know, if we can make the method as easy as possible, like you standing on that scale that you have at home, that's simple. You don't have to you don't have to do anything with it. And so, therefore, you're probably more likely to measure yourself that. Right.
So some tools are more convenient. Some tools work better on people with certain body types. But what do Dave Wagoner's research studies look like?
We want to know, does the method work for everybody? Right. So if I go back to skinful callipers, well, skinful calibres tend to work a lot better on people who are lean to average. It's easier to pinch a little bit than it is to pinch a lot. You know, the the more you have to pinch, the greater your error or mistake is going to be. Right. And so that is not a very good method for people who have an excess amount of fat. But for a lean athlete, it's pretty easy to get pretty accurate. With your punches on someone like that, we might compare one method again, maybe a low cost method, like a field method or something like your scale. If we're checking how accurate that is or checking the validity of that scale, we might do a research study entirely focused on that, like, well, we'll have a person be tested on that device. But then we'll also test them on one of our lab laboratory methods, like the bodpod or the next machine. And so a lot of what my research is, is can we can we validate some of these low cost tools? We're not going to get them to be as accurate as expensive laboratory methods like an X-ray device. Right. But how close can we get? The better the tool or the better the measurement device that you have, you can have more faith or more confidence in that percent body fat.
Wyatt Voice Over: [00:18:26]
That was my conversation with Dale Wagner. Thank you for listening to this episode of Instead. It was edited and produced by me, Wyatt Prober and Nick Vázquez as part of our work in the Office of Research at Utah State University.