Episode 29 - Why You Need to Stop Weighing Yourself with Gary Slater

Why You Need to Stop Weighing Yourself with Gary Slater

Hey you! Put the scales away and listen up! 

Many triathletes are interested in measuring their body composition. Whether it’s losing body fat or gaining muscle. Endurance athletes strive to be leaner, lighter and faster because you have to carry your weight across a long distance. 

One of the major challenges with this is actually trying to track and measure body composition change. You’re probably using the scales as a way of measuring. but this episode explains why there are major limitations to the scales. 

Listen in to my conversation with body composition manipulation expert Gary Slater. Gary is a fellow Advanced Sports Dietitian, Exercise Physiologist and loves using himself as an n=1 experiment for maximum muscle hypertrophy gains. 

Gary explains why you need to stop relying on the scales and what to do instead if you want to really track changes in your body composition.

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Episode Transcription

Episode 29 - Why You Need to Stop Weighing Yourself with Gary Slater

Taryn Richardson  00:00
Today on the podcast, I'm talking to fellow Sports Dietitian and Exercise Physiologist, Gary Slater. He's the programme coordinator for the Master's Degree in Sports Nutrition at the University of the Sunny Coast. And he's also the National Performance Nutrition Network Lead (say that 10 times fast) at the Australian Institute of Sport.

Taryn Richardson  00:19
But the reason I've got Gary on today is because he's got a really keen interest in body composition, manipulation, and measurement. And one of the things I see triathletes really struggle with is how to change their body composition when everyone wants to be leaner and faster. And then also how to measure that. If you don't know what you're looking for in terms of measuring body composition, then you're probably doing this wrong as well.

Taryn Richardson  00:46
Gary's always N equals one, he likes to test things and try things out on himself first. And when he's not working, you'll find him either kneeboarding at Moffat Beach or working on his own muscle hypertrophy in the gym.

Taryn Richardson  00:59
So what I want you to get out of today's episode is understanding, well first and foremost, why do you want to change your body composition? And if that is realistic and achievable and beneficial to your performance? And then two, how do you actually track that you are doing what you set out to achieve? Are you losing body fat and maintaining your muscle? Are you gaining muscle when you want to be gaining muscle?

Taryn Richardson  01:26
So we're going to dive a little bit into the science but also the practicalities about how to manipulate your body composition as a triathlete, whether it's useful and beneficial, and then how to measure it accurately so that you know that you're getting a true change. So I want you to stop weighing yourself constantly throughout the week or multiple times a day, and use some of the tools that we talk about today instead.


Taryn Richardson  01:56
Welcome to the Triathlon Nutrition Academy podcast, the show designed to serve you up evidence-based sports nutrition advice from the experts. Hi, I'm your host Taryn, Accredited Practicing Dietitian, Advanced Sports Dietitian, and founder of Dietitian Approved. Listen as I break down the latest evidence to give you practical, easy to digest strategies to train hard, recover faster and perform at your best. You have so much potential, and I want to help you unlock that with the power of nutrition. Let's get into it.


Taryn Richardson  02:34
Alright, welcome to the podcast, Gazza.

Gary Slater  02:36
Thanks, Taryn.

Taryn Richardson  02:37
So what I wanted to talk to you today about is body composition and how we measure it and how we manage it. Because I feel like that is probably your specialty/passion/obsession, maybe? 

Gary Slater  02:49
Perhaps. It's been a really interesting journey through that pathway. And, as with most things, if you've got a genuine interest in it professionally, there's probably some personal interests that have come from that. I kind of feel like I'm a constant experiment on myself in regards to physique manipulation.

Gary Slater  03:06
It's a really enjoyable space, but it's one in which I think a lot of people don't necessarily have a very good understanding in regards to the ways in which you can assess body composition. But then also, from an athlete perspective, how important body composition is to their overall sporting success.

Taryn Richardson  03:21
Totally agree.  With triathletes, being an endurance sport, in particular, it's often beneficial to be lighter because you're faster because you have to carry that weight across a certain distance, right? You've got to put one foot in front of the other. Often leanness is associated with fastness and speed but that's often at the detriment of not having enough energy availability or recovering really poorly or missing out on key nutrients because they don't actually know how to manipulate their body composition in the right way.

Gary Slater  03:50
You're so right Taryn, it's a really important issue that needs to be given a lot of consideration before a person goes down a pathway of exploring weight loss in this example. Because there are potential negative implications from it.  You've spoken about the limitation in regards to energy availability compromising fuelling and recovery. And so the quality of training just backs right off. If you're not getting quality training, you're not getting quality adaptations.

Gary Slater  04:15
The other thing we also recognise is that it can change the way a person perceives themselves. And there's also the other potential issues in regards to when a person is lean they increase their risk of loss of lean tissue or muscle mass. While people are focused on body fat, it's really important to keep in mind the muscle mass because it's the power generator. And so when we talk body composition, we should be talking about being able to assess both fat masses but also lean mass and skeletal muscle mass.

Taryn Richardson  04:45
That's one of the biggest mistakes I see athletes make is that they just use the scales as their measure of weight loss. But we know that the scales are a really poor measures of body composition change because they can fluctuate with so many different factors. Like how hydrated you are, or dehydrated you are, what your hormones are doing across a month, how much bulk you've got in your gut, like your stool bulk, if you've had more fibre the day before, or less fibre, if we're carb-loaded, so your muscle glycogen levels are really full, you might be a bit heavier.

Taryn Richardson  05:17
And if you maybe ate just more food that day, so people have no understanding really of the intricacies of what happens to drive the numbers on the scales. They just do it and then get disheartened when it increases for no particular reason, or it decreases and they're not really sure what's gone on there as well.

Gary Slater  05:36
I think you've summarised it really well. Like for me, scale maths is a really blunt tool for being able to track body composition change over time. And when I'm working with clients, I might set something up so they might weigh in a couple of times a week. And the reason why I do it a couple of times is to account for some of those nuances that you spoke about. Changes in hydration status, changes in gut contents, changes in muscle glycogen, all those factors, just add more noise into the measure, where you're trying to be able to pick up these really small changes in fat, lean tissue.

Gary Slater  06:06
Because, you know, for me, if I'm looking at trying to reduce fat mass for a relatively lean athlete, I might be looking at a change in fat mass of no more than, say half a kilo a week. And that can be difficult to be able to pick up when you've got all these other variables contributing to changes in weight. And again, the reason why I get away a couple of times a week, and I get an average of that - I'm not looking at the change between those two days, I'm trying to get an average of those and then compare one week to the next, but always in conjunction with another measure of composition. Because scales are merely a measure of heaviness, they're not a measure of composition.

Taryn Richardson  06:39
Do you have any tips for when somebody should weigh themselves and how they should weigh themselves to get the most accurate results?

The evidence would suggest the best time to weigh yourself is first thing in the morning. So you know if you've got to set a scales at home, jump up, have a quick wee, empty your bladder, jump on the scales and minimal clothing. If you're at home, jump on the scales nude and use that to start your day. When you've done your wee, have a look in the toilet, is it light or is it dark? And helping to use that to infer what's happening from a change perspective. And again, trying to get those couple of times a week, without becoming anal associated with it to be able to get an average value and then to get rid of some of that noise.

Taryn Richardson  07:15
So for all the data nerds and engineers and scientists out there that weigh themselves every day and look at trends?

Gary Slater  07:21
All you're picking up on - changes in weight from one day to the next - are all of those noise variables. Changes in muscle glycogen, changes in hydration status, how long was it since you did a number two? There's simply no value associated with that.

Gary Slater  07:34
I think it starts to have a negative impact on someone from a psychological perspective. No more than a weigh in once or twice a week. Do it first thing in the day. Don't weigh yourself at any other time of the day because all you're going to be picking up is food and fluid content over the day.

Taryn Richardson  07:50
Perfect. So if we're looking at tracking some changes in body composition, what's the best way to actually measure what's going on?

Gary Slater  07:58
The answer to that'll depend on the outcome that you're after or the measure that you're after. If you need an absolute measure of body composition, you need to know your absolute fat mass, your absolute lean mass, then you would need to go and get something like a DEXA scan.

Gary Slater  08:13
But for most individuals, and especially most triathletes because you're not a weight category sport or anything like that, we'd be looking at assessing body composition simply to be able to track change and to be able to assess. So you've set up a meal plan and a training program, you've set your meal plan up with your Sports Dietitian so that you're supporting fuelling and recovery, but also small reductions in body fat over time.

Gary Slater  08:14
A set of skinfold callipers in the hands of a highly-skilled technician such as a trained Sports Dietitian can be invaluable. Now you won't get an absolute measure of your composition, you won't get an absolute measure of fat mass or lean mass. But the changes in your skinfold values, as well as the changes in your body weight, can really help the Sports Dietitian to ascertain whether or not the weight loss that's coming off is coming off primarily as fat or it's a combination of other tissues. And then that allows the Dietitian to be able to further personalise the dietary strategy for you.

Gary Slater  09:06
Or we've cut back on energy too much and you're losing weight too quickly, you're not fuelling and recovering adequately and you might potentially be compromising your lean tissue, we need to increase your energy intake a little bit more. Or my weight's stable, my skinfolds haven't changed, okay, we need to be able to find some spaces in the day over a couple of days of the week, where we can create a little bit of a negative energy balance, that is calories in less than calories out.

Taryn Richardson  09:29
So for somebody that doesn't know what skin folds are, are you able to explain briefly what that is and how it works?

Gary Slater  09:35
Sure. Effectively, you know, we could talk about them being a very expensive set of barbecue tongs. And what we do with those that have got a dial on them similar to a watch face and you use that to be able to assess the thickness of a compressed double fold of skin.

Gary Slater  09:52
We typically do that across seven sites of the body, some on the lower body, some on the upper body, so that we accommodate the nuances of where different people store fat. And so we know that males typically store it around the central part of their body through the torso, whereas females primarily store it on the lower parts of their body. So we cover both upper and lower body.

Gary Slater  10:11
Doing that across the seven sites, we get a sum of those values and then we can use that information to be able to track change longitudinally. Some people have an interest in being able to try and convert that into an estimate of composition, so fat and lean tissue, and there are equations you can use to be able to provide those estimates. But none of them have been validated in a triathlon community, for example, and so that the numbers are kind of meaningless. And so we need to be able to get really comfortable in just looking at changes in weight and changes in the sum or set of skin folds.

Taryn Richardson  10:43
And making sure that your Anthropometrist, the person that does just skin folds, is actually qualified to do so too. I see a lot of PTs that go through a quick training in their course, try and do it, and the reliability of those repeated measures and tracking that change over time, like, you'll get a number, but that number is pretty wild - it's not likely to be particularly accurate.

Taryn Richardson  11:05
So if you're going to do skin folds, you want to make sure that you've got a trained Anthropometrist that has to do certain number of profiles every three years to keep their accreditation, keep their expensive callipers calibrated properly as well. There's a whole lot of cost and time and retraining every few years to make sure that you are doing them as accurate as possible as well.

Gary Slater  11:27
Perhaps people underestimate the skills that are required to go through that process. Because when you do it with an ISAK trained practitioner, as you're alluding to Taryn - ISAK’s - International Society for the Advancement of Kinanthropometry and the International Group. Aren't we so glad they just summarise it as ISAK?

Gary Slater  11:42
They’re the main training group that provides skills in that space. A level one technician - they've done at least three days, full time, covering off on the technique required for that, then go away and do 20 repeat profiles. They've got to come back within finite repeatability and that has to be done, as you've alluded to, every four years to maintain that qualification.

Gary Slater  12:02
The person that's doing your skin folds is not leaving little marks on your body from the pen marking - the little crosses. It's highly likely they're not ISAK qualified. It's a quick process, but without someone that has appropriate training in that space, the numbers are effectively random. And you couldn't use that to be able to track longitudinal change.

Gary Slater  12:21
Again, the great thing and I don't mean to repeat myself, is that any accredited Sports Dietitian will also be ISAK accredited, and they'll have the skills in being able to set up a meal plan for a person - to be able to support them on their weight loss journey. Perhaps more importantly, be able to make an informed opinion as to whether or not the person needs to change their body composition, but then also support them through that journey of weight loss and attract change, and then to be able to adjust their plan based on how they're responding. Because it won't be a set and forget, unfortunately.

Gary Slater  12:50
We can start off losing weight really effectively but then training changes for example, or we get some metabolic adaptations, that ensures that they might need to make adjustments thereafter. And that's again, where getting someone on board - an accredited Sports Dietitian - to support the person through that journey is just so very important - to help support the goals they're trying to be able to achieve but also to avoid the potential negative implications of that weight loss journey.

Taryn Richardson  13:17
You just answered my next question, Gaz, and that's just around, where would somebody actually start if they want to start changing their body composition? Let's take a step right back to that.

Gary Slater  13:28
I think the first question then is does the person actually need to change their body composition? I don't think people give enough consideration to that. And they think “Weight loss journey, no negatives, I'm just going to get lighter and leaner and my run is going to be so much better”. But as you alluded to right at the start, there are potential negative implications. There might be compromises in fuelling and recovery. You know, sustained for a very long period of time, we know that there can be more significant health and performance detriments as well.

Gary Slater  13:57
And that's where I think going and engaging with a Sports Dietitian, perhaps having an assessment of their body composition through skin folds. The great thing about triathlon is we've got some normative data on elite individuals. So you can compare where you're at versus an elite, and then make an informed opinion with your Sports Dietitian, but probably also your coach, when you think about the type of training you're doing at the moment.

Gary Slater  14:20
Is there likely to be a benefit for me in undertaking a weight loss journey, or I'm actually doing really well right now and I need to focus more on being able to better support fuelling and recovery and getting better training adaptations? Because weight loss is not always associated with performance enhancement. And we need to keep that in mind.

Taryn Richardson  14:39
Often in practice, I see people that come in because they want to lose fat for a particular race. And they're under fuelling and bonking in long sessions and then playing catch up on rest days. And one of my strategies I implement with a lot of people is actually giving them more fuel where they need it.

Taryn Richardson  14:56
So making them eat strategically through those bigger, harder, longer sessions where they actually are burning more muscle glycogen. And as a result of better fuelling, they can train harder, burn more calories through their session, and often will lose body fat by doing that, by actually fuelling more aggressively. And it's hard to actually see that unless you're doing something like skin folds because that change often isn't reflected in the scales.

Taryn Richardson  15:22
They might gain weight on the scales through that process and if you weren't doing something like skin folds to see that change of reduced-fat and increased muscle, you'd be disheartened by that whole process.

Gary Slater  15:34
And this comes back to what we're alluding to before in regards to scales being a really blunt tool. I often find, especially with age group triathletes that some people come into triathlon through their weight loss journey, and started to do some exercise, they started to run or ride and they've got into triathlon. And I think they come in with that mentality, of restrict, restrict, restrict. And what they need to recognise is that there are days in the week where you've got big training volumes that you need to allow your food intake to come up.

Gary Slater  16:03
You know, one of the things that separate athletes/triathletes from their sedentary counterparts, is that your energy requirements vary from one day to the next. And I find some of these triathletes feel really comfortable in moderating their energy intake on a lower training day or a non-training day, which is fine. But they feel really constrained in regards to allowing their energy budget, their food intake, to come up on the days when they're doing more work. And again, that's the value of a Sports Dietitian.

Gary Slater  16:31
A triathlete can't eat the same seven days of the week. You'll have bigger fuelling days, where you need to put more carbohydrates in the system and you need to feel comfortable with that. And on days when you're not doing as much work, then you can moderate things off a little bit. And you know, the other point that comes to mind for people on their weight loss journey is they feel more comfortable in pulling calories back on those big training volume days, you know, you're compromising fuelling.

Gary Slater  16:57
I don't think about, you know, creating a calorie deficit over the seven days of the week. There might be three or four half days of the week that we create a calorie deficit. And typically, I try and do that as far away from training as possible, so that you're not compromising fuelling and recovery.

Gary Slater  17:12
The other big thing that you mentioned before, this should be a fat loss journey when justified, as opposed to a weight loss journey. And the only way you're going to be able to track changes in your fat mass is to measure body composition. And as we've said multiple times, scales are a very blunt tool for assessing composition. Go out, engage with a Sports Dietitian, get some regular skin folds, get a baseline assessment to be able to ascertain whether or not it would be appropriate for you to be able to consider reducing your body fat levels.

Gary Slater  17:42
Look at your training block over the next 10 to 12, 16 weeks, because that's potentially the timeframe that might be required to be able to support your weight loss journey. And then make an informed decision as to whether or not it would be appropriate to start that now or “No, I'm going through a big block and readiness for an important race. I am going to be a much better athlete at this next race by actually supporting fuelling and recovery goals, as opposed to just trying to focus on weight loss”.

Taryn Richardson  18:08
I'm so glad you said that, Gaz. One of the biggest mistakes people make is eating the same thing all the time as triathletes. And when you do three disciplines, when you're swimming, cycling and running, because we're overachievers, no training day is the same. And so you need to eat differently on a lighter day versus a heavier day and a long, long session on the weekend potentially, or a brick.

Taryn Richardson  18:30
That's one of the first things I do with people - is teach them that. Something I go through in the Triathlon Nutrition Academy really deeply is how to actually periodise your nutrition to your training periodisation. So I'm so glad you said that as well because it's something I bang on about all the time. And it's nice to have the same message repeated from a different brain.

Gary Slater  18:50
It’s just so important. Like the small number of athletes that I engage with if it’s a triathlete, for example, I tend to spend most of the session actually getting a good understanding of their training. Because it's the training that dictates the energy budget, it's the training that dictates the fuelling requirements for that person and recognising that it can vary over the seven days of the week. And then it'll also vary over your micro and macro cycles. And that's something that I think we take for granted as nutrition care professionals, but it's very difficult for an athlete to be able to achieve. And that's why I think an investment to see a Sports Dietitian to be able to set up a training program and then race plans is the best investment you'll make.

Taryn Richardson  19:31
You heard it here first folks. People spend a lot of money on a coach and a training program and they spend 10 to 20 grand on a bike and then they eat shit food. I guess it doesn't make any sense to my Dietitian brain that you would do that. Because I think there's a sweet spot where training intersects nutrition and when you have both of those, that little Venn diagram, when that overlaps, there's this sweet spot in the middle that I call the supercharged zone.

Taryn Richardson  19:56
That's where you've really dialled in your nutrition to support training. And you still may be performing in sessions, and you still may be driving some fat loss and muscle gain if it's really perfectly planned. But that's where you're actually going to get the best bang for your buck out of your training and your money spent doing all of the things, as well as your body composition there as well. So thanks for backing me up in that Gaz.

Gary Slater  20:20
Yeah, we're probably not very good at FIGJAM-ing ourselves as a profession. And look, the other thing, when you're talking about a justified fat loss journey - that it takes time. You know, from thinking about half to maybe a maximum of a kilo fat loss per week and a person's got six kilos to lose of fat. That might take them three to four months to be able to achieve and for me, the longer the slower, the better.

Gary Slater  20:45
But I think their head can get in the way. And they're not seeing these changes on the scale and like what's going on, I need to cut back more, and then, they really cut back, they compromise training quality, they bonk on a long ride, all they think about is food, they go and gorge on food, they feel bad about that. And so it becomes a really vicious cycle.

Gary Slater  21:02
And I don't want to sound like an advertisement for Sports Dietitians, but it's a relatively complex issue that requires highly scientific information to be able to piece together a meal plan that will support fuelling, recovery and optimisation of body composition. And then having a person also that can help track that change and to be able to manipulate that to further personalise it for the person.

Gary Slater  21:29
And that's where having a Sports Dietitian in your back pocket to be able to support you through that weight loss journey, I think is so important. Because they're able to track what's happening for you, not on average, but what's happening for you. And then to be able to further personalise it, to achieve that that long term goal so that you can get to the start of the next important race, have achieved your body composition goals, but also had really really good training quality. And know you're going to race a whole lot better as a consequence.

Taryn Richardson  21:57
Unreal. So let's shift gears a little. You mentioned DEXA before. What is a DEXA? And when would it be useful for a triathlete to add that to their toolkit?

Gary Slater  22:07
So DEXA has primarily been used to be able to assess bone health. It's the diagnostic tool that you would go to an imaging centre to be able to get your bone mineral density assessed and to be able to assess your overall bone health. Probably over the last 10 to 15 years, there's been a recognition of the potential value of DEXA to be able to track body composition change.

Gary Slater  22:28
It's nuanced by the fact that there is a small amount of radiation exposure associated with it. It's not different to the amount of radiation exposure you get in normal daily living, what we call background radiation exposure.  But it is a source of radiation exposure and as a consequence, there'll be a limitation on the number of DEXA scans a person can have. Typically that's no more than about four a year.

Gary Slater  22:49
And so that's where the challenge is, like if we're thinking about this weight loss journey, and we want to be able to track longitudinal change. If you could only have a DEXA scan every 12 weeks, it's not actually going to allow you to be able to further personalise your intervention. You could go 12 weeks since and say “Oh, we haven't created an energy deficit, damn and my body fat levels haven't changed”. And that's where things like surface anthropometry become a benefit because you could do skin folds every four weeks or so with a person. So you're not allowing too long a time period without assessments to be able to then adjust your meal plan.

Gary Slater  23:22
Some of the benefits associated with DEXA; it provides us with information in regards to whole body composition but also regional composition. I used to love when I was doing a lot of DEXA scanning, sitting down and being able to tell a person if they were left or right-handed. Because if your right side dominates, you're opening doors, you're carrying bags with your right arm, you're carrying more lean mass and more bone mineral density in your right arm compared to your left.

Gary Slater  23:44
It provides us with a measure of fat mass, fat-free mass as well as bone mass. It's often been termed the gold standard for body composition assessment. That probably isn't justified. It's a good tool, but you need to know how to utilise it appropriately. And I've seen numerous examples where a person is able to manipulate how they presented a DEXA scan for a decrease or an increase in fat-free mass of upwards of a couple of kilos.

Gary Slater  24:08
One of the beauties of skin folds is that they're so robust. It's not influenced by diet or exercise beforehand, your body weight is obviously. But the DEXA scan will be influenced by what you consume food and fluid wise in the day beforehand and also exercise. And so typically if you go to get a DEXA scan from a group that is really informed and know how to utilise DEXA, there'll be guidance provided for at least the day before your DEXA scan to make sure that you present for your DEXA scan the following morning, really well hydrated, glycogen replete, not super compensated, you don't carb load for it.

Gary Slater  24:40
But we don't want it to go in there, you know on a Monday morning after you've spent six hours on the saddle the day beforehand. And the person would come in overnight fasted, bladder voided, a little bit like what we're doing will scale weight, to get that accurate measure of body composition.

Gary Slater  24:55
I guess the question is, you know, does a triathlete need to know their absolute fat mass and their absolute lean mass? If it's about going on a body composition change journey, and I'd argue they possibly don't. You know, if it was about a person coming back from injury, you know, let's say they've had to have knee surgery or something like that and I've had to completely unload their leg for a period of time, you know that they're really vulnerable there to losses of lean tissue, we know how important lean tissue is to success. And so you might have a DEXA scan there to be able to assess the lean tissue or the muscle mass that's been on the injured leg compared to the non-injured leg to be able to make sure their rehab has progressed well.

Gary Slater  25:33
I think for the majority of people, the most valuable tool is merely tracking changes in skin folds over time in conjunction with a good measure of body mass. As we alluded to, before waking, do wee-wees beforehand, jump on the scale semi-naked. If you are weighing in at a commercial gym or a swimming pool, I'd probably keep your clothes on!

Taryn Richardson  25:53
So with lots of body composition measures, you can cheat the system in a way. I don't think there's a way to cheat skin folds. But DEXA, you can certainly cheat the system, a BIA, there's other ways you can cheat, measuring your body composition. When it comes to a DEXA, how do we know that there's been an actual change in body composition shift, compared to say skin folds, which we're measuring at the millimetre level?

Gary Slater  26:18
So what we're talking about there, Taryn, is precision error, or as I like to call it, just the noise in the test. Every single test that's done has noise in it. We could use a simple blood test. You can get your blood cholesterol taken, if you run it through the machine two times, you potentially get two slightly different values. With both skin folds and DEXA, we know there's noise in the test as well.

Gary Slater  26:42
We know the factors that contribute to that and we can minimise that. As I've alluded to, you go to an imaging centre that they really know what they're doing in regards to things like DEXA. They'll provide you with guidance in regards to what to do from a food and fluid intake perspective, the day beforehand, same thing, try and do it after a day of rest, come in overnight fasted, etc, etc. When all of that is done, you can still have noise in the measurement of upwards of one to two kilos.

Gary Slater  27:09
And so you think about if I want to drop four kilos of fat mass, and that takes me 10 to 12 weeks, I've got to see a change in my DEXA scan of greater than one to two kilos, depending on what the noise in the specific machine you're using, before I can say it's a real change. And that I guess, is one of the limitations associated with DEXA for tracking longitudinal change. You've got to have a real chance that's greater than noise in the measurement. And we also need to know what the noise in the measurement is.

Gary Slater  27:36
And so you probably need to engage an imaging centre that have actually gone through that process. It's relatively detailed, you know they'll typically get a minimum of 20 people come through, often they'll do a test, retest. So they DEXA scan them, they hop off a DEXA scan and they hop back on. I don't think that's probably the best way to be able to look at the noise and the measurement because it doesn't take into consideration what we call biological error, or the changes in muscle glycogen content, the changes in gastrointestinal tract contents, the changes in hydration status that we would see with a person during their weight loss journey. And so the way that you might assess that noise is, you would scan them today, but then scan them again tomorrow. And that noise in the measurement we know increases when you do a between day comparison. And it can be upwards of a couple of kilos.

Gary Slater  28:22
When we look at the noise in skin folds, with a trained technician, you're talking about noise of about one-two millimetres across skin folds that could vary from say 40 mm in an elite male athlete, through to 90 or 100 mm or more in a female athlete. And so one of the other beauties about skin folds is it's just such a robust tool. It's not influenced by food intake, fluid intake beforehand, exercise. Although, it's not very nice to do skin folds on an athlete after exercise, obviously, because they're a bit sweaty.

Gary Slater  28:57
But we're typically trying to infer body composition change from the changes in skin folds plus weight. And obviously weight is influenced by food and fluid intake, hydration status, etc. But you can do skin folds at any time of the day, you might just use that waking weight as your measure. And I'm not concerned if an athlete does that assessment of their body weight at home on their scales. The scales could be out by 10 kilos, I don't care. As long as they're consistently out. Because all I'm really interested in is that change score during their weight loss journey as opposed to the absolute value.

Taryn Richardson  29:29
That's perfect Gaz. So for any triathlete out there that's looking to change their body composition, whether it's to lean up, put on more muscle, first and foremost, probably need to engage somebody that can help you do that in an evidence-based way. And then please please please, if you learnt nothing else today, throw out your scales. Just stop weighing yourself every single day and then multiple times a day because the numbers are only going to go up as the day goes on. And utilise something with a skilled professional like skin folds. So you're looking for somebody that's ISAK accredited.

Taryn Richardson  30:04
I'll actually do another episode on skin folds and we'll deep dive into some of the things around how it works and when you would do it and what you need to look for if you're getting someone to do your skin folds. Like Gaz said earlier, if you haven't been marked up, then chances are, your results are going to be a little bit bogus.

Gary Slater  30:22
Great summary, Taryn.

Taryn Richardson  30:24
So stop weighing yourself all the time. Maybe once or twice a week, first thing in the morning, nude ideally, unless you're out in public. Do a wee, don't eat or drink anything and that is ideally what your weight is. Maybe you start doing that once a week to track some change. But don't be disheartened if it bounces around a fair bit.

Taryn Richardson  30:45
There's no point weighing yourself every day. That's only just going to get messed with your head. And then try and use something as a tool to track the change in body fat and muscle with something like skin folds.

Taryn Richardson  30:57
And hey, if you wanted to do a DEXA, let me know, send me a message and I can direct you on to some places that do a good quality DEXA scan. Because like anything, there are places that don't do a great scan and there are places that do a good scan. And they're all going to give you a piece of paper that says here's your data. Whether that data is actually true and accurate or not is another thing. And hey, don't get me started on BIA, that'll be another episode. We're not going to deep dive into that rabbit hole because Gary and I might get a bit all hot and sweaty and flustered talking about BIA scans.

Taryn Richardson  31:30
Well, thank you so much for joining me Gaz. I know you're spending time with me on your holidays. So I'll let you go, to go and go for a surf or grab a coffee or take the dog for a walk and enjoy the rest of your break.

Gary Slater  31:40
I'll do all three. Thanks, Taryn.


Taryn Richardson  31:46
Thanks for joining me for this episode of the Triathlon Nutrition Academy podcast. I would love to hear from you. If you have any questions or want to share with me what you've learned. Email me at [email protected]. You could also spread the word by leaving me a review and taking a screenshot of you listening to the show. Don't forget to tag me on social media at @dietitian.approved so I can give you a shout out too. If you want to learn more about what we do, head to dietitianapproved.com. And if you want to learn more about the Triathlon Nutrition Academy program, head to dietitianapproved.com/academy. Thanks for joining me and I look forward to helping you smash it in the fourth leg - nutrition!

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