Ep. #945: Grant Tinsley on the Science of Measuring Your Body Fat

Mike: Hello and welcome to another episode of Muscle for Life. I am Mike Matthews. Thank you for joining me today to learn about measuring your body fat percentage, measuring your body composition. This is a topic I have been writing and speaking about. Intermittently now for many years, but that I continue to get asked about because it’s just one of those perennial topics, and to deliver some content that is a little bit different than the stuff that I have produced on now.

Measuring body composition in the past, I invited my buddy, Dr. Grant Kinsley to come on the show and talk about the good, bad, and ugly in measuring body composition. And in this interview, Grant talks about how effective all of the most popular devices and methods are. And, I was pleasantly surprised.

To learn that there are some consumer grade devices that are pretty dang good at determining just how fat we are. And in case you are not familiar with Grant, he is an assistant professor at Texas Tech University. He is the director of the Energy Balance and Body Composition Laboratory, and he is a certified Strength and Conditioning Specialist.

And certified sports nutritionist grant has over 150 peer reviewed journal articles and abstracts with his major research interests being sports nutrition strategies, body composition, assessment techniques, and intermittent fasting in active populations. But first. Do you sometimes lack the energy and the motivation to get into the gym?

Do you sometimes want to hit the snooze button instead of the squat rack? And are you sometimes just not able to give a hundred percent in your workouts? If so, My pre workout Pulse is for you. It is a 100 percent natural supplement that increases energy, improves mood, and sharpens mental focus, increases strength and endurance, and reduces fatigue.

And the reason it’s so effective is simple. Every ingredient in Pulse is backed by peer reviewed scientific research and is included at clinically effective levels. The exact amounts used in the studies that found benefits. Pulse is also naturally sweetened and flavored and it contains no artificial food dyes or other chemical junk.

And all that is why I’ve sold over 850, 000 bottles of Pulse and why it has over 11, 000 four and five star reviews on Amazon and on my website. So if you want some help getting fired up, zeroed in, and ready to crush your workouts, then you want to try Pulse today. Go to buylegion. com, b u i l e g i o n.

com, slash Pulse, and use the coupon code MUSCLE at checkout and you will save 20 percent if it is your first order with us. And if it is not your first order, you will get double reward points. That is 10 percent cash back on that order and know that if you don’t absolutely love Pulse, just let us know and we will give you a full refund on the spot.

No forms, no return even is necessary. So you can’t lose. Go to buylegion. com slash pulse. Order now, use the coupon code MUSCLE, save 20%, try PULSE, risk free, and see what you think. Hey, Grant, welcome to my podcast. Thank you for taking the time to come educate us on body composition. 

Grant: Absolutely. Thanks for having me.

Mike: Yeah. And for people who are watching this on YouTube, or I guess there’s video on Spotify as well. It looks like I’m recording this with a potato because I basically am, this is my laptop. I think this laptop is five years old. It still works fine, but the camera, this is what that camera looks like.

And my normal web camera fancier one doesn’t want to work today. So this is what we’ve got. Anyway, we are here to talk about body composition. I’m excited to have you on the show to talk about this because this is something that you and your lab specializes in your research. And I suppose where we could start is maybe just a quick definition of the term body composition, just for people who aren’t familiar.

It’s different than just body weight. And then I’d love to hear about this study that I believe you said it’s submitted. So it’ll be. I think that’s what you said, but it’s the work of its complete on these by I don’t want to throw out terms people don’t understand yet, but on these devices like scales, handheld devices that you can just buy on Amazon and how accurate are those really at assessing body composition.

Grant: Yeah. So I’d love to dive into all of that. As you mentioned, I think it’s always good to get terminology straight, in the fitness community, people usually think something when they hear body composition, probably often they’re picturing like a body fat percentage or the percent of your weight that’s body fat.

And that is one of the variables we often look at. But really, from a broad perspective with body composition, we’re just talking about how you break up So most people have this understanding that body weight as a metric is not the most informative. Maybe you personally have been the same body weight at different times in your life, but you’ve looked a lot different.

You’ve felt a lot different. You’ve been able to perform a lot different. So really, body composition, just broad principle. How do we break up the body? At a simple level, most of the methods we have access to, we’ll be doing something like trying to split all of our body mass into fat mass, muscle mass, and fat mass.

And fat free mass, which would just be everything else. But we can build more advanced models. We can look at things from more of an anatomical perspective, where we look at true skeletal muscle, adipose tissue, bone, things like that. So it can get fairly complicated, especially in a research setting, where we do have access to devices that can slice up the body in different ways, so to speak.

But in terms of consumers, as you mentioned, many of these simpler devices Really are giving you a body fat percentage, which again is just related to the amount of fat you have, fat mass in the amount of fat free mass you have. Yeah, if you’d I’m happy to go ahead and dive in and elaborate a little bit more on our body fat scale study.

Yeah. Yeah. That’d be great. Yeah. So as you mentioned, we haven’t quite submitted it. If we were recording this in another week or two, it may be submitted, but we do have the research done. We’re just finalizing a few parts of the manuscript. We have published a good chunk of this in abstract form at a few conferences over the last year or so.

From the outset, and I’ll probably say her name again, I want to give a huge shout out to a doctoral candidate in my lab, Madeline Seidler, who led the day to day of this study and has been involved from day one. We had conversations in my office talking about this idea and she’s done a fantastic job rolling with it.

She’s starting the third year of her PhD here at Texas tech. From a big picture perspective, we were interested in Kind of some of the rigorous methods we use for body composition assessment in the lab, but really producing results that would be more useful to consumers, just people interested in fitness even personal trainers or people trying to assess the body composition of their clients.

And as Mike, one of the really popular categories of body composition tools are these home body fat scales. So for anyone listening, if you’ve seen these scales, they often have like silver plates on them, like little circles you step on. Most of these scales are using a technology called bioelectrical impedance analysis, and they’re essentially passing very small, imperceptible electrical currents through your body.

And the device essentially knows what it’s injected into you in terms of electricity, and then it measures what it receives back. And it uses that information along with quite a few assumptions to estimate things like the fluid content of your body and from there estimate your body fat percentage.

So there is error involved in every step of this process, but nonetheless, these are really popular devices. They’re affordable. So in the study that we’re starting to discuss now, we looked at 15 different devices. 14 of these were consumer grade devices. We essentially went to amazon. com, looked at some of the best selling home body fat scales because we wanted these results to be applicable to a wide range of consumers.

And with those scales, the price range from about 24 up to 350. with the majority of those falling below 100. So a reasonable price point for a consumer who’s really interested in this, or again, for someone like a trainer who doesn’t may not have a large budget for body composition testing, but wants some device they can use with their clients.

As a side note, I’ve talked to others about this before, but one of the devices we use is one that you see sitting around on the counter of half the gyms in America, and that’s the little handheld body fat device where you grab it and you’re just like squeezing it as hard as you can.

And you’re like, I 

Mike: think that was the first I’ve ever, any of these devices or methods of assessing body composition that I, that’s the first I can remember at least. 

Grant: Yes, yeah, no, it seems to be common experience in the fitness realm that, there’s that one sitting on the counter and I don’t know, they use it with clients as if we’re getting a personal training program or something like that.

So we did actually include that, that device. But from the big picture perspective, we were looking at all these consumer grade devices and the plan for the study was to bring in individuals, test them with all these devices and then also test them with our laboratory methods using our gold standard laboratory method, which I’ll describe in a moment.

And essentially look at a few items, one at a single point in time, how accurate are these devices compared to our gold standard method? But then even more importantly, how can these devices track changes over time? So these individuals after we’d assessed them in the lab, left and continued living their life for a few months.

And then we brought them back into the lab, repeated all the assessments. Both the gold standard and these other body fat scales, and we’re able to really see how well these devices could track changes over time because most people who have these scales, they’re assessing periodically over time, maybe even more frequently than they should to see.

And, they’re hoping to see that body fat percentage number go down or that fat free mass number go up. So just to get into the study a little bit more, we essentially recruited healthy adult females and males. We ended up with 73 individuals. With a really even split between males and females, these were all generally healthy individuals.

We didn’t require them all to be physically active because we wanted this to span the range of activity levels. So we had some individuals who were just recreationally active and we had some individuals who are higher level athletes. So we got a pretty wide range of body compositions and activity levels represented in our sample.

Yeah. Prior to our first assessment of these individuals, we of course, screened them for some eligibility criteria. We had everyone abstain from exercise and vigorous physical activity for at least 24 hours before they came in. We had them fast from food and fluids. We recommended a certain amount of fluid intake the night before.

We did all these control measures so that when they were poor after an overnight fast, we were fairly confident their body was rested, fasted. There weren’t some, any strange fluid disturbances which is particularly important with this type of technology that relies on body fluids. So once we had them in the lab, we performed our gold standard method.

Which is called a four compartment model. And really, we have to use multiple different devices to build this model. Some people may be familiar with DEXA. DEXA, or Dual Energy X ray Absorptiometry, is one of those methods. Another method we use is the BODPOD. or air displacement plethysmography, which just gives a view of the three dimensional space.

The body takes up we use the calibrated scale and we got a body water measurement with a technology called bioimpedance spectroscopy, which uses mathematical modeling to estimate body fluids. So we have all these kinds of complicated research grade devices that we assess individuals with. And we pull different variables from each of those, put them into this validated equation and we get what’s called our four compartment model body fat percentage.

So that was our gold standard. So we assessed that and in the same visit in a randomized order, we assessed individuals on all 15 of these bioimpedance devices. So 10 of these were what we call foot to foot tests. scales. So these are the ones that look just like a body weight scale and they have those like typically silver electrodes on the surface.

Someone steps on there. And in addition to taking a body mass measurement, again, these scales are injecting a little electrical current, quantifying what they receive back, and then plugging that information typically into some type of black box proprietary algorithm and spitting out the body fat percentage.

We had 10 of those that were foot to foot. We had four that were hand to foot, so devices that had both electrodes that were in contact with your feet and your hands. So these would often have a little pullout handle where individuals are grasping onto this handle in addition to standing on the platform.

And the idea here is that the current is being injected not only into the feet and completing that electrical circuit through the lower body, but also through the arms. And the idea is that you can get a better picture of the total body here. And then the last device, the one we were just joking about, was the little handheld Device looks almost like an old, I don’t know, some type of video game controller or steering wheel or something like that.

So we had these 15 devices. We had everyone assessed by those devices two times. So back to just get a simple test, retest reliability, which is looking at how much can a value vary. If someone gets on the scale, steps off and steps back on. And if you’ve ever looked at Amazon reviews for any of these products, or if you’ve messed around with them yourself, there are some disgruntled users who will say I stepped on, I was 24 percent body fat. I stepped off and I stepped back on and I was 26 percent body fat. They’re disgruntled about that. So it is an important point to consider just the test retest reliability. So that was one component. Again, the second component was just at this one point in time at this first visit, how accurate was each device compared to our gold standard.

And then after this visit, again, we let people. Leave the lab. We did not control what they did, but they had the option to return 12 to 16 weeks later, and we had 37 individuals who agreed to come back. So they came back. They were tested. We didn’t know for sure what we get, but actually turned out really nicely.

Essentially, it was a good result. Almost perfect split half individuals gained body fat by our gold standard method, half lost body fat, which is really what we wanted to see. We just wanted the natural variability and body composition. People are changing lifestyle, exercise, different stress levels.

Some of these were college students. We just wanted natural variability to take place. And that’s what we saw. So they came back in, we performed all the assessments again, and then we were able to look at the actual change. So we could look at it and say okay, for this individual. If our gold standard method said they gained 2 percent body fat, what do all these other methods say happened?

So I’ll pause there for a second. That’s the data collection. And there were a lot of results. I’ll try to distill it down. But do you have any questions or comments at this point? Now that we’ve discussed the setup of the study. 

Mike: No, that was a great introduction to the results.

And just a comment that I know just from many people reaching out to me. So the 2 questions I’ve been asked the most with these devices are 1. Are they 15. 18. accurate? And then if they’re not, are they at least consistently inaccurate? Okay, fine. If they’re not perfectly accurate, then maybe the an individual reading doesn’t mean that much.

Maybe you can understand it more as a range, but if they were at least consistently inaccurate, then if you wanted to watch it, you could look for trends, just how you could watch your body weight and pay attention to trends. But of course, if they are just inconsistently inaccurate, then that would make them just useless.

Like why even bother, right? Absolutely. So yeah, 

Grant: you hit the nail on the head of what we were trying to get at here. So yeah, that one point in time, and that’s where most studies stop. And we’ve done studies like this in the past. It’s a lot easier to get someone to come to your lab one time, test them, and then you never see them again, rather than come to the lab and be like, okay, please come back in 16 weeks.

We really want to see what happened to you. But yeah, that’s what we were trying to get out with that second visit. It’s just what you said, some of these devices, at the group level, maybe they’re just systematically overestimating body fat, but like you said, if you’re doing that consistently, we might still be able to answer the more important question of, has my body fat increased or decreased over time?

So from the big picture perspective and I’m going to do my best to summarize here because we have. 15 specific devices once the study is published, I’m happy to share. And I could even list them out now, but many of the best selling body fat scales on Amazon, we have all these devices, we have lots of metrics, we looked at lots of different things.

So I’ll paint with kind of some broad strokes here from a big picture perspective. And this is exciting to me as a researcher, we did see a lot of separation really between the performance of devices. So there were some that are definitely in the category of bad across the board. They’re inaccurate.

Maybe they’re inconsistently inaccurate. They’re not really useful. The magnitude of errors are so large that you would need someone to, have their body fat before it’s Oh yeah, you saw a change in body fat. So that’s about half the devices. The other half had performance that depending on the context could be acceptable.

So there were devices, even cheap devices, say sub a hundred dollar devices that. That performed surprisingly well. I was actually a little bit shocked. We had for comparison, we had a 12, 000 bioelectrical impedance device in there as a lab laboratory grade comparison that was thrown in with all these consumer devices.

And there were some of these cheap consumer devices that performed nearly identically to this 12, 000 lab grade device. So that as a, is a general Finding is encouraging for these home body fat scales, but it’s very important that the results are looked at on a case by case basis because we had some devices that if you look at them, if you look at the price, if you look at how they’re described and marketed, they seem like they should perform similarly.

And we had some that were incredibly different. in their performance. So there were several ways we looked at the performance. Some were what are called like group level metrics. We’re just saying overall, did this device overestimate or underestimate body fat? That’s often where studies stop. And that, that can be useful.

But again, we want this to be maximally benefit the consumer and most consumers, most users of these devices. They don’t care if we tracked 20 of them doing the same nutrition exercise program. They care about the one and equals one. They care about, themselves. Did I gain or lose body fat?

So we also looked at a variety of individual level metrics and something that again, my doc student Madeline had this very good idea was to generate all these rankings. So we have all the devices ranked first through 15th in different categories. So like individual level accuracy at one point in time.

Individual level accuracy. If you’re trying to actually track a change in body composition over time so all this will be available in the manuscript and hopefully will be very helpful to consumers where they can find their particular device or if they’re in the market for device, they can look and say okay, the category I care about most is accuracy in tracking in one individual.

Cause I’m going to use this in myself or my clients and they can look through and find say the top ranked device at the price point that works for them and use that device. Yes. I would say, in general the devices that have electrodes in contact with the hands and feet, those tended to usually be in the top half of the performers.

But surprisingly, there were some just foot to foot devices that just look like the scale you step on that were also near the top In terms of performance I know these are all broad statements. And for those who have a specific scale, I definitely encourage you to follow up on this.

We’ll try to share this widely as soon as it’s published, because we think it will be of interest to, to really anyone using these scales. But again, from the big picture, some of these, not worth using, we’ll probably add more confusion than benefit. But there is actually promise in this category of technology, even on these relatively cheap consumer grade devices, that if you pick the right device, you can actually get some useful data.

Mike: Interesting. And are there any details you can share on why you think the some of these devices, because I’m a little bit surprised to hear that I basically wrote these devices off some time ago and didn’t bother using them myself and didn’t recommend them. Interesting. I tell people just pay attention to your weight, maybe pay attention to your waist circumference.

There are a few things if you want to take some measurements, but from the research that I had seen, I, again, I haven’t looked into this in some time, but. From the research I had seen, I was like these things are all over the place. So I just I just wrote them off. And so I’m a little bit surprised to hear that, that some of these scales in particular I was expecting the four points to, to outperform for obvious reasons, but do you have any thoughts to share as to why some of these devices actually performed well and maybe better than other scales or just two point devices?

Grant: I do have a few thoughts and I’ll start out by saying that I completely agree with what you said about tracking body mass and circumferences, some of those other metrics, even with the best performing devices here, I think for the longitudinal tracking, one of the best performing devices had, if there are any like Stats nerds in there.

It had 95 percent limits of agreement of about 3. 5%. For others, this would essentially mean if you saw a change in body fat, it’d be reasonable for the real change in body fat to be about 3. 5 percent higher or lower than that. So that’s a pretty large range. If someone’s interested did I gain or did I lose 2 percent body fat?

And you go, 3. 5 percent above or below that, you’re clearly looking at some reasonable values that could be negative or positive. Like you actually lost body fat. You actually gained body fat. So that’s a big caveat. Even the better performing devices have a margin of error. It’s incredibly difficult to be very precise and accurate when you’re tracking body composition of one person over time.

So that’s a caveat. So I completely recommend what you were saying, Mike, Yeah, that’s a good point, especially for fit people, right? Even 

Mike: for 

Grant: women, 

Mike: even for if women, let’s say, they’re fit women and they’re around 20 percent body fat, give or take, and they want to, you’re still talking about enough error to confuse somebody, where they’re like looking in the mirror and they’re feeling their clothes, but this thing says they got fatter.

Like, how does that work? 

Grant: Yeah, no, you’re absolutely right in a good proportion. It was depending on whether it’s the cross section, like the one point in time or the tracking analysis, 40 to 50 percent of the devices systematically. Overestimated body fat in lean individuals and underestimated body fat and those with higher body fat.

So essentially there were a lot of devices that were pulling people towards the middle. So you might be really lean stepping on there and it’s showing you at a higher body fat than you really are. Conversely, if you have a higher body fat percentage, you might be stepping on there and it’s like.

pulling the body fat percentage down. So there were a whole category of devices that displayed this characteristic I’m describing which is called proportional bias. It’s bad. It’s something we don’t want. So again, many of these devices you look at and be like, okay, no, this is bad. This is bad.

It’s whittling it down to a select number that were potentially useful. And again, then I would still pair it with what you said with body mass with circumferences and say, does this make sense? Like you were saying, if you’re like, I look better, my clothes fit better, whatever my performance is up.

But this scale showed body fat change in the wrong direction. Then I would not put too much, weight on that. But yeah, in terms of the reasons something we saw emerging is some of the manufacturers that have been around longer. So like Tanita is example, manufacturer that’s been around a long time.

They’ve had a lot of research and development personnel look at their equations over the years. Some of those seem to perform much better than some of these newer companies. There are lots of kind of companies that just do consumer tech type products that they’re like, Oh yeah, we can do this body fat scale.

And they produce a device and the device itself maybe is similar to say like a cheap to need a device or one of these other devices. But I think there are some cases probably where the people putting the equations together. I want to say didn’t do it right. I don’t want to be too negative but they might not have known the best way to put the equation together to where it would scale outside of their validation population.

And they also might have validated the scales and a very homogenous, like small. group with some of those issues, like I was just saying, where lean individuals and individuals with higher body fat were systematically miscategorized, that could speak to an issue with how well the equations were validated.

So I think part of it, the scale itself is one. Components, some might use better quality components. They might be getting cleaner data. But the other component that I also strongly suspect is how good of a job their scientists did developing these body fat equations. And as I mentioned a little bit earlier, the hard thing here is that.

None of the manufacturers will disclose equations. We have a table put with article about whatever information we could glean about each device. Madeline, I know contacted a number of companies trying to get information. And most of the time, the person you can get in contact with, One probably doesn’t know, but also won’t disclose.

And they’re like, Oh, this is proprietary, but, from these hints, I think that some equations, some people maximize the utility of that bioelectrical data they get and others are just like, Oh yeah, we’ll throw this in equation like this. This seemed to check out in our sample of 20 people we tested this on, let’s go ahead and mass produce this and sell it. And, the consumer won’t know any different. 

Mike: And brands I would guess at least in many cases, brands are actually not doing any of that work. They’re just going to a manufacturer and the manufacturer says, Oh yeah, sure.

We can make that for you. And if they do even ask questions beyond If that, in many cases, that’s probably the, okay, here’s my, here’s the order, right? And we’re going to slap our brand on this then. Yeah, maybe they would ask for some validating information, but I’m speaking from experience, I guess maybe more in the supplement world, but especially if you look around on Amazon, I’m sure you guys and gals ran into this, that you have a lot of, there are a lot of Chinese companies now that they’ve spawned.

I’ve seen so many random brands, especially in electronics, and these are not brands you would recognize, but there are a lot of these products now that have just flooded Amazon, particularly with electronics. And so if you don’t recognize the brand name, if it’s just, it might even sound like something legitimate.

It might just be some random company over in China. That’s just throwing their stuff up on Amazon. And. They might not care about the quality of the thing. That’s a growing problem on Amazon. 

Grant: Yeah, no, that, that’s that’s certainly fair. And, there were, some trends emerge like the more reputable companies, but there, there were the occasional oddballs where there’s a scale where we’re like, yeah, the scale, we’re not too optimistic where it actually came out, more highly ranked than we’d expect. We saw some of those trends but again, I’d go back to, it’s a little bit of a case by case basis based on what we saw. Even ones that appear similar. So yeah, lots of interesting kind of wrinkles here and, I wish every company was completely transparent with what they did or didn’t do to develop their equations and just would show us the equation, but that’s not the nature of it.

We just wanted to, test what we could test and report what we found. So consumers and practitioners can make more informed decisions. 

Mike: Yeah. And for people listening who want to read the paper and they want to see the ranked lists, do you know approximately when it will be available?

Grant: Yeah, I would be I want to give an estimate. I would say a few months, the peer review process is not super speedy. I think this is a really clean manuscript. It’s really tight. We’re submitting to a fairly reputable journal. A very reputable journal, a very highly ranked journal. So we hope that the expedite everything.

There are a few abstracts that are already. Available that I know I’ve posted about my social media. If any of that is linked, I’ll grab them and I’ll put them in the show notes. So whatever’s available. Yeah, no, that sounds great. And I’ll definitely share widely once this is fully available. We also actually already have a public listing.

This study was not funded by any of these companies. We just use my own research funds from Texas tech to purchase these devices. And there’s nothing inherently wrong with industry funded research, but for this particular one, none of these. Companies played any role. So we have this registered on clinical trials.

gov. So if individuals are curious, I can also send a link to that. The full list of every device we looked at is already posted publicly. And we did that just for openness and accountability. So it’s not like we’re dropping some device off the list because, the manufacturer, whatever pressured us or anything like that.

So the full list is out there. If You’re someone that uses one of these devices and you’re curious, you can look at the list and if you see your home body fat scale on there, then you can, wait with bated breath until it’s published and you can see all the results. 

Mike: And last question about that paper before we move on.

Are there are Are there any devices that that emerged from the analysis that you think could be useful? You implied that this was the case, but then you had mentioned these margins of error. So I just wanted to follow up with a question of, for people who are into their fitness enough to want to track their body composition, were there any devices in the 25 or so that you purchased that you feel Would be useful for that.

Grant: Yes, I think there are and I’ll I’ll consult my spreadsheet over here because there are so many different rankings. So we did ultimately get to an overall ranking like considering the cross sectional. So the one point in time accuracy, both for groups and individuals and the long term tracking accuracy for groups and individuals and the reliability.

Mike: Which is what most people that, at least who have reached out to me, that’s what they care the most about is, of course, it would be great if it were very accurate in an individual reading, but minimally it needs to be consistently accurate ish enough so that they can just, throw it in their spreadsheet, they can Take their readings once a week or whatever.

Grant: Yeah, no, absolutely. Yeah, looking at my list here for the individual tracking. So again, just tracking changes, looking at that one domain rather than our overall rank. The top few were those, what we call octopolar, that eight points. So that the hand electrodes and the foot electrodes some of the best performing ones, one was actually an Omron device.

So not just The handheld one, but the Omron HBF 516. So it’s still very affordable. I think it was under 60 but has hand and foot electrodes. The next couple, there was a Tanita device that also had the Tanita BC 568 inner scan, so another one that utilize those. Had the hand electrodes also one other one that I thought was really interesting that was actually ranked in the overall rankings.

Second highest out of all of them in the first highest was our 12, 000 device. So we were a little bit glad to see okay, that at least holds up. Imagine this, the 60 device beats that, okay. Yeah. I’d be like, Oh didn’t spend that money. But one device that’s really interesting, that was a little bit higher price point is 350.

So it’s the most expensive of the consumer grade devices, but it was new and it’s from a very good manufacturer was the in body H two O N. So those involved in researcher who have been in like a bunch of supplement stores, have them some gyms, maybe familiar with these in body devices in body, it’s a good manufacturer.

I know a little bit about small amount about what they do under the hood from communications with their science staff. And I’d say it’s a reputable company. So they have this again, price points a little bit higher at 350, but this in body H two O N, which was another one that had both the feet electrodes and hand electrodes it performed well, and I’m actually involved in some other data analysis from a separate university looking at the same device and it’s performing well there also.

So I think it’d be a nice one. That’s a little bit. Higher end, maybe a, personal trainer or something that’s wanting to have these reports for their clients. Have a little bit of a nicer device, a not that looks or everything, but a classy, nice, solid looking device. Yeah, it performed really well.

It was in those top few for tracking individual changes. And again, it was ranked second out of all of them. Second, just behind the research grade device and the overall ranking. That’s when I like I’ll disclose that in body had no involvement in this study. Several years ago, they loaned the device to our lab just as a loan not research funding or anything that we use for a study or two.

And then it’s been long since returned, but I’ll give that just as a disclaimer because I have had interactions with that company before. But anyway, so yeah, across Tanita Omron and in body, like we were talking about common thing is all those are pretty well established body composition manufacturers.

Each of those had both a hand and foot electrodes. So those performed really well, but once you go past there, you do get some that are just foot to foot, including one of the Tanita devices. But, yeah, it’s an initial glimpse on specific results. Those three are ones that performed pretty well for the individual tracking.

That’s great. That’s 

Mike: great. Hey there. If you are hearing this, you are still listening, which is awesome. Thank you. And if you are enjoying this podcast, or if you just like my podcast in general, and you are getting at least something out of it, would you mind sharing it with a friend? friend, or a loved one, or a not so loved one even, who might want to learn something new.

Word of Mouth helps really bigly in growing the show, so if you think of someone who might like this episode or another one, please do tell them about it. Let’s shift gears now and talk about some other methods of assessing body composition. So something that I will get asked fairly often is just what’s the best method?

What’s the most accurate method, right? The four compartment analysis is something that’s done in the lab. So we can probably exclude that. You described that. And but for what, for something that, people can do at home, people will ask me about calipers. How about that? Or they will ask about these devices that you discuss.

They’ll ask about different measurements that you can take and plug them into calculators. Can you talk a little bit about and, even though it’s not accessible, people will ask me about DEXA or, somebody will show, maybe it’s a video of somebody getting a DEXA scan and it’ll say 10 percent and the dude looks absolutely shredded, maybe even striated glutes shredded.

I’m exaggerating a little bit, but we’re, there just seems to be a little bit of a disconnect, like really 10, 10 percent when he’s covered in veins. 

Grant: Yeah, I’ll answer the main question, but since you finished on it, I’ll mention the DEXA question. One important thing to realize is, I think sometimes from the outside DEXA is a perfect example because, the evidence based community, they’re familiar with DEXA.

They’ve either had a DEXA done or seen it. They’re aware. It is a really good method. Yeah. When you’re on the inside, I’ve used multiple different manufacturers of Dexa across multiple universities, multiple different software versions, and you realize that there are quite a few things you can do in the software that change the results.

And I’m not talking about willful manipulation, but things like settings, you can change different settings that could reliably change the body fat percentage by, say, 5%. And 5 percent absolute, right? Just so people understand. Yeah. So really, meaningful changes where you could have the same shredded striated glutes person jump on one Dexa, get it, get the scan done.

They have the results. You could change some of the settings and reprocess the same scan and you’d have quite different results. So that could be 

Mike: the 5 percent turns into 10 or something. 

Grant: Yep, it certainly could be. So there, there are some of those settings there’s some error in every device even like the pre assessment standardization.

We talked about a little bit with fasting fluids, all this, we, we’ve done studies where you can trick Texas, so to speak by carbohydrate and creatine and fluid manipulation. So depending on where someone’s assessed or how depleted or they are at the time of assessment, that, that could affect.

Affect their readings beyond just what you would see visually. 

Mike: And I’ve seen what I think is some manipulation as well. On the other side, I’ve seen I can think of a fitness influencer or two has, who has used DEXA scans to try to promote their programs and yeah, DEXA scans are. Are often represented as the gold standard infallible.

And he’ll hop on the deck side and get a reading of five and a half percent. It’s no, he dude, he’s lean, but he’s not five and a half percent. That’s a nice maybe eight or 9%, but that is not getting ready to step on stage. And so that’s just a good thing to point out that for people listening, Don’t just take DEXA readings at face value.

They might be right. They might not be right. 

Grant: And the same principles we were talking about with the BIA apply that it’s really hard to accurately track an individual. So even in that case, maybe the person’s not willfully manipulating, but they might be that person who, because of some of the characteristics in their body, they’re systematically underestimated by DEXA.

So they’re like. They’re happy. They’re not going to argue if it’s saying they’re five and a half percent body fat, even if, they may be in their heart of hearts think they might not be five. That they 

Mike: would have to step on stage at 1%, but 

Grant: yeah. Yeah. So yeah, point being, there’s air involved, their settings, this and that transitioning, to the main question you’re asking about best method.

I think you alluded to this already, but I’d say the best method, certainly depends on the context. If you’re talking to someone who has a flexible tape measure and some 10. You’re saying, Oh yeah, go, pay 200 you’d go drive five hours and pay 200 to get a DEXA scan done somewhere.

That’s the best method. That’s probably not the best method for their context. It’s certainly not the best method for repeating frequently over time. I’m a big proponent as others are, I know Bill Campbell often says this, which coincidentally enough, Madeline Seidler who helped so much and really led the BIA study.

She studied with Bill Campbell before she came and studied with me. So she’s had a lot of body comp stuff. But I’m a big proponent of those practical measures and not doing too much with them. So for example, if you’re interested in fat loss and you can take these raw skin fold thicknesses at different sites on your body it might be best to just keep those raw and interpret them as much as you want to plug those into equation and distill all that down to 13 percent body fat, it might be more informative to watch those over time and say okay, I have a lot of skin fold sites that are not changing, but I see this abdominal skin fold.

This is actually decreasing over time. That’s something that I want. That’s consistent with my goals that might get washed out when you’re pooling all of these together and throwing it into a body fat equation. Similarly, circumferences, like you said, if you’re seeing your waist circumference go down over time, the scale is not budging.

Maybe it’s even a home body fat scale and that number is not changing or it’s just randomly oscillating around. That, that’s an encouraging sign. Okay, waist circumference is decreasing. Maybe my upper arm circumference is increasing. Maybe I have some amount of, so called recomposition going on right now.

I’ve. Increase my protein intake. Recently, I’ve, increased the intensity of my training and so on. And as the more trained someone is, you’re dealing with small margins and it’s you’re not going to see large changes and it’s hard to track those small changes you do see because of the, little bits of error.

But I’d say there’s certainly nothing wrong. 

Mike: I’ve stopped bothering with that because take calipers, right? I wouldn’t say that it requires a lot of skill to take caliber readings, but there are right and wrong ways to do it, right? Even the amount of skin that you pinch, if you’re not consistently pinching the right amount of skin.

And there are spots too, that Are hard to do yourself and really it’s probably better if somebody else does them. And then like you said, also the margins of improvement are so small that they overlap with the margins of error. And so I’ve found just as a random comment that what has been more.

useful for me if we’re talking about tracking muscle gain is just using performance in the gym as a proxy and watching my performance with given working weights progress first in reps in reserve where, okay, that weight felt a little bit heavier a month ago. That’s a good sign. Eventually that turns into being able to get an extra rep or two with the working weight.

Eventually that turns into some extra weight on the bar. And of course, I just go, Hey, if that’s happening I’m gaining, I know I’m gaining at least a little bit of muscle and it might not show up if I were to take measurements because we are talking about such small amounts. And if I mess it up a little bit, it’s not going to show.

Grant: Yeah, no, I think that’s completely fair. And I don’t think there’s. I certainly don’t think there’s anything wrong with the method like that, even if you wanted to periodically, and even if it’s every several months, every six months, every year, if you’re just one big picture I’m, I’m wanting to maintain this, whatever I’m at for the next decade, two decades, three decades, I think a periodically check and say okay, within, reasonable marginal margin of error, is there anything I’m just not realizing that I didn’t realize?

Because, general population wise, maybe not, Fitness community quite as much, but general population wise, things tend to drift over the years and decades in a direction you don’t want. So even something as simple as that, ideally your general practitioner, someone might do it, but maybe not, a simple waist circumference every six months or something, just to make sure something’s not creeping way you don’t want to.

And again, I’m getting more general population there and less, like peak fitness, but, 

Mike: no, that’s a good point. But I guess you could, like you said, you could do even in the case of someone like you or me, maybe we would, we could do check in measurements every so often. If we were so inclined, I suppose for me, it’s to that point of maintenance where I’ve accepted that this is about what As big and strong as I’m going to be, no matter what I do, if I really wanted to push for more, of course, there’s a little bit more to be had, but I’m pretty happy with where I’m at and this is I’m getting ahead of myself because something that I’ve gone through the whole experience of body fat percentage and being really into trying to get to the number and eventually, you.

It’s just, do I like what I see in the mirror? If I feel like I’m too fat, cool. I’m just going to restrict my calories for a month or two. And now I like what I see in the mirror. Okay, great. What number is that? I don’t know. It’s in the range of what I like the most is probably between eight and 11 percent or something like that.

And exactly where I’m at in that range. I don’t care as long as I’m in that range. That’s what I like. 

Grant: Yeah, no, that’s completely fair. And it’s funny as a researcher who does a ton of work in this area, there are definitely times I zoom out and think about that and does this matter?

And, it does. And some of the research we do is for other contexts and, there are lots of health and disease implications, other things we do with body con, but yeah, it’s certain at a certain fitness level, you definitely can legitimately question like, okay, how much does this, Truly matter at this point.

What does the number I’m getting matter? So yeah, I would say, circling back around for anyone, interested in body comp assessment. Certainly, there’s nothing wrong in being interested in them, but I’d interpret everything as a grain of salt. I’m always a proponent of multiple metrics, especially, if you’re doing some of these potentially less accurate tests, but if you were, if you do have even one of these better home body fat scales, pairing that with tracking your weight, considering your performance in the gym, maybe periodic circumferences or skin folds, Kind of getting that holistic look cause again, just, I think I saved this earlier, but say again, if you’re getting a, some number that’s tracking the wrong way, but everything else is good, you feel better close fit, better say, like your method with performance is better, all of that.

You certainly wouldn’t want to make some large programming change. They’re like, okay, and you scrap everything and start over because. My home body fat scale said I went up 2 percent 

Mike: Or get, just get, yeah. Or just be demotivated or discouraged by it. I understand that again that wouldn’t be the case now, but there was a time when I just wasn’t informed enough and maybe would have been discouraged because it’s just conflicting information.

And If you place too much credence in, it could be a device or a method like, skinfold. I know a lot of bodybuilders were, will swear by the skinfold method and and if that gives you a number that is discouraging, it might lead you to question some of these other methods of assessment.

Grant: Yeah. No, I agree. As one random side note I’ll just mention because it’s another class of technology we haven’t talked about, but that our lab has done a lot of work in or really interested in is I think there’s a lot of promise in terms of just reliable assessments and easy assessments. There’s a lot of promise for three dimensional optical imaging.

Oh, that’s good. I wanted to ask you about that. Okay, great. Yeah. So there are lots of these standalone scanners like Stike, you fit 3d size stream and so on that you could actually like here in town, our crunch fitness, for example, has a fit 3d. And those are showing up, I think, in more and more facilities.

But with phone applications, we’ve recently been evaluating. Some of these there, phone cameras are good enough and the technology is getting good enough on 3d scanners that there are some free phone apps where you can set up your phone and rotate in front of your phone and it builds a little 3d avatar of your body.

And the nice thing there is that it can pull circumferences very reliably. So it’ll have some definition based on the pixels at seeing on where your waist circumference is. So there’s no guesswork really of am I measuring this in the same way or can I really measure this particular something?

Circumference. If I’m trying to measure my chest circumference, do I have it? This flexible tape measure at the same point in my back if I’m measuring it by myself. So I think there’s some promise there for just like simple things, even if it’s for a periodic check in where technology can assist even in a free capacity without purchasing a particular device, but could assist with tracking some of those basic 

Mike: metrics.

What have you seen with Some of the more expensive devices, like what you’d find in a gym. My gym has one. I haven’t bothered with it, but 

Grant: yeah, so the test retest reliability is very good in general from our lab and literature most devices would be comparable to a trained tailor in terms of the reliability.

So the only times I’ve seen like a manual assessor outperformed the reliability of these circumference assessments. is if the study is using, yeah, again, someone trained equivalent to a tailor. So if you’re talking about, your random gym buddy or something, he’s just like slapping on and measuring might be better quality than that.

This is another example where I think the raw inputs, the circumferences in this case would be. Potentially more useful than plugging into a body fat equation. The body fat equations have a little bit of work to do, and it makes sense. They’re trying to estimate something internal, your body fat, just based on surface metrics and not even getting like a skin fold or something like calipers.

So there’s some challenges there. But in terms of the circumferences, if you’re like, okay, I want to track my upper arm circumference. My thigh circumference and my waist circumference over time. I want my arms and thighs to get bigger and I want my waist circumference to get smaller. They’re sufficiently reliable that they, if you assess the same way not after a big meal one time and fasted the next time and all of that if you assess the same way they do have pretty small margins where they could track small, but real changes in these circumferences.

So I would say I’m generally optimistic on them. But again, with some caveats that like if it’s spinning out the body fat percentage, say the one at your facility. The, I wouldn’t put too much weight on that, but if you’re interested in tracking, some individual circumferences, I would say it’s a decent technology for 

Mike: that.

If I get, if it’s consistently tracking those circumferences, even if the body fat percentage were wrong, I suppose if it were consistently. wrong at least could show you a trend, right? It could. 

Grant: And the hard thing on there is it’s similar to BIA, but I’ve seen a little more under the hood because I’ve been involved with a couple of companies helping them develop some of these equations.

But it just depends on what circumferences they’re pulling. So I was even advocating, there’s some, there are even different versions of the waist circumference, depending on if they’re doing the narrowest or the navel or, halfway between where they think the ribs are and the hips are, all this.

It depends different companies pull different circumference inputs because it can measure anything on the body as a 3d avatar. They’re all kinds of weird ones. It’s I can measure from like the tip of this shoulder down to like your opposite butt cheek, just all this random stuff.

They can pull any input they want because they’re not actually there with a date measure. It’s just, based on the avatar. I think there’s a lot of room for growth for what inputs are pulled, how they’re weighted in equation and all that. Yes, you’re right that I think you get tracked there.

A hard thing is it’s such an early technology that some of these devices are like pushing a body fat equation update like every few months, which is not helpful to the consumer where it’s like all of a sudden it’s different by 5%. They’re like, Oh yeah, we changed the equation. We don’t use like this anymore.

We use this one. So that’s another reason why. They don’t do that as much with actual raw circumferences. It’s usually just what they’re doing with their circumferences. So yeah, the relative youth of the technology is another reason why I am a more of a proponent of the circumferences. Now 

Mike: you, 

Spoke, I think, implicitly about this already, but I think it would be worth just explicitly commenting on it.

And that is the Accuracy or the usefulness of what’s the name of the method. So you’re supposed to take some measurements. This is for body fat percentage, and I don’t, I haven’t done it in a while. So you could tell me, I don’t remember the exact measurements, but you take a few measurements, you plug them into a calculator and it spits out, I believe it was, it, is it a Navy thing or a military thing?

Oh yeah. Like the army body fat equation. Yeah, I know there’s one of these things out there that makes it seem very simple and I know then many people turn to it because it seems so simple. 

Grant: Yeah, that, that’s a really interesting question. I had another student just defend his dissertation and it focused a lot on military and military relevant populations with that equation you’re describing and 3D scanners and four compartment, all the things we’ve talked about rolled up into one.

Okay, so it’s not perfect. We know that. Like for. If you’re just looking at like next circumference and waist circumference and males and like neck, waist and hips and females, this is certainly not a perfect measurement. Like we were just talking about with 3d scanners, we’re not measuring anything internal to the body, but we’re trying to measure something internal to the body.

So you already have a little bit of a disconnect there, but surprisingly, when you look at it, there’s a reason why it’s hung around. And, of course, from say the military perspective, they need something simple. They use like height for weight tables and then this body fat equation, like as needed.

But they need something really simple. We’ve had some discussions with personnel there about whether even just moving to 3d scanners, they could at least eliminate some of the like tester to tester variability and how these are assessed, but the equation does. Okay. It’s not as bad as you’d expect.

We went into this big project. And over a hundred individuals looking at this equation and many others. And we expect it to be like, Oh, there’s the antiquated, Navy army military equation. And it did pretty well for the people who developed it were, I don’t know, onto something like this scaling with the neck circumference.

It’s weird, but like neck circumference matters for just. A natural build, like correcting the waist circumference for someone’s natural build. So anyway I certainly wouldn’t take it and have someone plug it in there and, and this is funny, but an anecdote, even when the military people were talking about is how people would train their neck really aggressively and try to get all this neck hypertrophy to trick the equation.

Mike: That’s neck training. Seems a little bit of a thing. I’ve been asked more about it recently than in the past. It just seemed that in the world, people asking me how do I make my neck is as thick as possible? I’m like, why, what do you mean, just do more squats. Come on. What are you doing?

Grant: Yeah. Yeah. So anyway, it, it certainly isn’t like the best method, but it’s all, context dependent. If you’re screening thousands of people and just trying to like have some rough cutoffs in this night, it does pretty well. We’d never say Oh yeah, you don’t need a DEXA scan ever.

Just yeah, give me your neck circumference, your waist circumference. That’ll tell you like for sure your body fat percentage. So I don’t know. Those are, that’s just a random collection of thoughts. 

Mike: Yeah. Yeah. It sounds like it’s maybe similar to BMI in that regard, but for body comp where, yeah, sure.

They’re at a population level. It’s pretty useful at an individual level. It can it can underestimate, it can overestimate body fatness. Depends on how fit you are, blah, blah, blah. Yeah. How much you’ve trained your neck, all that good stuff. So then I’m assuming the thicker the neck, if you’re training your neck explicitly to try to trick it, then that brings your body fatness down.

That’s the point. Yeah. Yeah. So like you can be overweight and you’re like, if I just get a really thick neck, then I’m going to pass this test. 

Grant: I think that’s the idea. How successful people have been when they try to do that? I’m not sure. 

Mike: Yeah. Yeah. How much neck hypertrophy does it take?

That’s funny, but no, that’s great. And that that’s all the questions that I had for you. Is there anything that is still sitting in the back of your head that we haven’t discussed that you think we should cover before we wrap up? 

Grant: I don’t think too much. I just reiterate that I don’t think there are many methods that are just Complete trash.

I think every method you should take with a grain of salt. You can maximize the benefit of any method you’re using by being rigorous with how you standardize before assessments, not just doing these haphazardly. Even in our paper, we’re about to submit, we advocate for things like taking multi day averages.

So if you’re able to perform the same assessments on a couple of days in a row and average across those days, that can help reduce some of that day to day random error. So yeah, I think whatever method you use, if you use any. Just apply it consistently ideally look at a couple different metrics.

Don’t read too much into each one just take it with a grain of salt consider performance What are your goals is body comp your number one goal and you’ll sacrifice performance for it Or is it performance and you’re hoping body comp comes along for the ride? So yeah for anyone who’s like really in the weeds on body comp or obsessing over I would just think about how you could use it to benefit you in some way without again basing all your decisions on it or placing all your value in a number, being spit out by a $35 scale that you got from Amazon.

And again, for anyone interested in the consumer grade BIA devices, we’ll certainly share that, but hopefully that will help inform decisions. ’cause some people might be using a scale where they’ll look at this and say, okay, we actually need to get rid of this. This is. Worse than nothing, but some people might have scales where it’s okay, this isn’t everything, but it’s a piece of the puzzle that can help myself or my clients or so on.

Yeah, I think those would be my only parting thoughts here. 

Mike: Go ahead. One follow up question on that actually is if you are going to be using one of these BIA devices, let’s say you have a good BIA device. You had mentioned previously a couple of the things that a couple of the factors that you Controlled for to get consistent readings, but maybe we could just wrap up if you want to share with people at home.

All right, here are the important things to make sure that you’re getting consistent readings and or, and also accurate readings. Yes. 

Grant: No, that’s a great question. So I’d say at a minimum you want an overnight fast from food and fluid. Sometimes I won’t get in all the weeds here, but we’ve done some studies just looking at simply someone comes in the lab and ingest water and how much does that affect their bio impedance measurements and it it can be meaningful depending on the type of technology.

So I’d say at a minimum eight plus hour overnight fast from food and fluids. So ideally, the morning is the ideal time to do this void your urinary bladder if you need to defecate or if you have a normal morning bowel movement, go ahead in. Do that just everything you can standardize of course, rested overnight, ideal be longer.

Like in our study, we had a 24 hour abstention from exercise. So if you do incorporate rest days or active rest days assessing body comp, the following morning might be an ideal time to do this, doing that consistently. So you wouldn’t necessarily want to assess sometimes the morning after a heavy leg day, the previous evening.

And other times assess after a rest day. So consistency, even on what you did the day prior is important. General awareness of dietary patterns. If you track and if you’re, or if you’re just consistent on your diet over time, you may have this address, but just be aware, especially if you’re doing carbohydrate manipulation or if you have, you’re changing up your diet in a way that dramatically affects the water content of your food.

Foods, some of those things, even the preceding days can affect measurement. So I would just be aware if you are tracking, try to think not only overnight but the previous day and kind of habitual diet. What things could you be doing that might be influencing this? And I’d say the more those things you button down, the more noise you eliminate and the cleaner your signal or the actual value you’re trying to get comes through.

Those would be the main things, food and fluid, rest, kind of awareness of your overall dietary pattern exercise patterns and so on. And I think if you do have someone else involved, for example, helping with skin folds circumferences and so on, having the same person do that over time and apply that consistently would be the ideal scenario.

Mike: Great tips. Great tips. This was a great discussion grant. I really enjoyed it. Very informative. And why don’t we wrap up with where people can find you’re active on social media, share a lot of great educational information there. And then anything else you’d like people to know about let’s let them know.

Grant: Yeah, so I’d say if you want information on me, I have a personal website that’s just my name, granttinsley. com. I have my academic CV up there. I have information about our lab equipment, our research team, my home gym, just all that type of stuff on the personal website. In terms of social media, I’m probably most active on Instagram and my handle there is just granttinsley.

com. underscore Tinsley, T I N S L E Y underscore PhD. And I typically share new research on Instagram in my website also has links to PubMed and other websites that kind of keep track of all the research 

Mike: output from our lab. Awesome. Thanks again for doing this, Grant, and I look forward to the next one.

We should brainstorm something else we can talk about. Absolutely. Thanks for having me on, Mike. I hope you liked this episode. I hope you found it helpful, and if you did, subscribe to the show because it makes sure that you don’t miss new episodes, and it also helps me. Because it increases the rankings of the show a little bit, which of course then makes it a little bit more easily found by other people who may like it just as much as you.

And if you didn’t like something about this episode or about the show in general, or if you have ideas or suggestions or just feedback to share, shoot me an email, Mike at muscle for life. com muscle F O R life. com. And let me know what I could do better or just what your thoughts are about. Maybe what you’d like to see me do in the future.

I read everything myself. I’m always looking for new ideas and constructive feedback. So thanks again for listening to this episode and I hope to hear from you soon.