Transcribed using AI transcription, errors may occur. contact Mikki for clarification
00:09
Hey everyone, it's Mikki here. You're listening to Mini Mikkipedia on a Monday. And today I wanna chat about things that we think are true or believe to be true, which are in fact not supported by science. And look, clearly I could probably have an all day podcast on this because I'm pretty sure there'll be so many things out there that would fall under this category. And I've definitely talked about some of them in the past, but I was interested just to

00:38
to dive a little bit in some areas, and they may seem sort of random to you, but they were just things that popped into my head. After I got a text from a friend of mine, Christy, who is a super smart researcher, and I want to say she's at Queen's University, but I'm not sure. I'm pretty sure she's in Kingston, and she's currently undertaking her PhD. In addition to being a collaborator on a number of papers with other super smart

01:06
people such as Tommy Woods, Andy Galpin, Andrew Kutnick, names that you'll be familiar with either from this podcast or in other realms of their work. And Kristy is actually up there as well. And so last week I was talking about metabolic flexibility and I had mentioned that zone two training improved mitochondrial biogenesis. And she texts me and she's like, Mickey, can you just show me the research for that? Because I've been diving into this and I cannot find it.

01:35
anything that supports the notion that zone two training does anything to mitochondria, much less improve mitochondrial biogenesis, which is the proliferation of mitochondria and also just the expansion of mitochondria. Now I'm like, huh, okay, good point. Where did I hear that from? And I delved back into my files and saw an article from Peter Atiyah, who is a guru who I listen to all of the time, and I'm sure you do as well. And he, he's

02:04
often says that zone two training improves mitochondrial biogenesis. He's not the only one. Loads of people say things like this. I'm like, I think that's where I got it from. When I went into actual research, just to see whether... I mean, the reality is, as soon as Christy texted and said that, I'm like, okay, there isn't actually anything to back that up because if anyone was going to know, she was going to know. She researches the area.

02:33
clinical trials to support the idea that low intensity training does anything to mitochondria actually. And if you look at the research, which I then did, mitochondrial adaptations occur over and above a threshold. And that threshold is due to volume and intensity of training. Having said that, there is still no evidence to support long duration zone 2 training has

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benefits for mitochondria. Now, there are preclinical studies, which are essentially rodent trials, showing that low intensity training improves mitochondrial dynamics, such as structural changes, fusion and fission, which is the merging of two or more mitochondria, or helping mix the contents of partially damaged mitochondria.

03:29
So diluting the effects of mitochondrial DNA mutations, which is important for distribution, quality control and adaptation. And there are other related functions such as a cellular stress response, calcium homeostasis, apoptosis. However, there is nothing in the human data to suggest that this is what zone two training does. And so Christy called me out on it, which was awesome. And it just...

03:58
got me thinking, you know, there's probably so many things which we just repeat verbatim without even really giving it a second thought because it comes from someone we trust. And I know this happens all the time. I see it all the time. And clearly I do it a lot of the time myself. So this really gave me pause as to other things that one I might think and say without actually doing a dive to see whether or not it is true or otherwise, but certainly what...

04:26
what do other people just repeat verbatim, which actually isn't supported by research? Another thing related to mitochondria actually is the idea that fasting improves mitochondrial biogenesis, which is the synthesis of mitochondria, and also mitochondrial dynamics. And in fact, a paper which Christy was involved in, in writing, really does challenge that dogma as well. So the background to this theory is that skeletal muscle mitochondria

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play a crucial role in our overall insulin sensitivity, energy metabolism, and nutrient utilization. And mitochondria are highly adaptable and respond to energetic stress by initiating mitochondrial biogenesis, which is the creation of new mitochondria. So there are activation of two key enzymes, AMPK and PGC1-alpha, which play a key role in triggering these mitochondrial biogenesis.

05:24
So therefore stimuli that activate that pathway will also be beneficial for overall health. So while exercise is a known stimulus, although as I've just covered, not low intensity exercise, fasting in rodents has also been thought to activate this axis, which promotes metabolic and mitochondrial health. However, the widely accepted idea of fasting induced AMPK and PGC1L for activation

05:52
actually lacks solid evidence from human experiments. And this prompted Christy and her colleagues to perform a systematic review of the evidence. And they identified 34 studies, seven in human, 21 in mice, and six in rat, that compared the AMPK PGC1 alpha response to fasting in skeletal muscle. And what they found was that in human studies, the activation of that pathway during fasting

06:21
is largely absent. And while rodents showed some response, the evidence was nowhere near as strong as expected. So these findings also challenge that existing dogma that fasting improves metabolic health by stimulating mitochondrial biogenesis in muscle, and in fact implies that the benefits of fasting are more due to caloric restriction. So this is super interesting as well. There are so many things that we hear and that we just believe.

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but there's not that much data to support it. Something else in that realm, which you probably will be familiar with maybe, is the fact that we should drink eight glasses of water a day, and this came up in a conversation I had with the client even this week. And unsurprisingly, this also lacks strong scientific support. So the eight glasses of water a day theory is a widely recognized guideline, but its origins are somewhat unclear and aren't based on robust scientific evidence.

07:20
And one of the earliest references to the idea comes from a 1945 recommendation by the US Food and Nutrition Board. They suggested that people consume around about 2.5 litres, which is approximately 8 cups of water a day, including water from all beverages and food. However, the same report also mentioned that much of this daily intake can come from food and other beverages, not just water itself. And this caveat is often overlooked.

07:48
And so over time, the recommendation was simplified and misinterpreted into a straightforward rule. Drink eight, eight ounce glasses of water a day, the eight by eight, this is what it's known as, which equals around about two liters or half a gallon. And it became popular advice because it was easy to remember and promotes the importance of hydration. However, there is a complete lack of scientific evidence from that. And hydration needs vary greatly depending on a person's size,

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activity level, climate the climate, and overall health. And the body often signals when more water is needed through thirst, and many foods also contribute to hydration, such as fruit, vegetables, things like that. And of course, the eight glass rule might have been further propagated by public health campaigns, doctors, and media, just because it is a simple and practical way to encourage people to stay hydrated. I mean, don't get me wrong, water is absolutely essential for health, and I do think that

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A lot of people do need to be drinking more water for their overall health, but there's no really good basis from a scientific standpoint that you actually need two litres of water a day. In fact, there was a recent study that was just done, a survey, that reported the water intake of over five and a half thousand men and women, aged up to 96 years old from 23 countries. The research involved people drinking a glass of water.

09:15
which they had a stable isotope added to it, which is called doubly labeled water, which shows how quickly the body processes it. It's completely fine, not at all dangerous, it's just something that they can add to track the water as it processes through the body. People's intake of water was found to be higher in hot and humid environments and at high altitudes, as well as among athletes, pregnant and breastfeeding women, and people with high levels of physical activity. Most people

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that was found only really require around 1.5 to 1.8 litres of water a day. Therefore, speaking to the idea that a one-size-fits-all policy for water intake isn't supported by that data. Another recommendation that I have used in the past and others have as well is using 0.33 mils per kilo of body weight. You could even use that as a starting reference point knowing that it is all fluid and not just water.

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I think there just has to be a balance in terms of what it is you do drink in a day. I personally, I don't think it's a good thing if all you ever rely on is coffee, tea, sodas, even diet sodas as opposed to actually just water because you do place not stress but additional work on your liver and kidneys to filter and extract and get rid of the other constituents of those beverages. And that is something to be mindful of.

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In addition, if you're drinking say six cups of coffee a day, you could well be impacting your central nervous system in a negative fashion by increasing that central nervous system response and increasing anxiety. Again, that is not everyone. And that is actually just one example of why you probably shouldn't only consume coffee. There will be people who need more. And I did mention a couple of those, or those groups of people just previously.

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There is one other group where people will require more water than what was found in this study, and that is those on a lower carbohydrate diet, because it can be harder to hold on to water if carbohydrate stores are depleted. And this is because we store water alongside carbohydrate in our muscle cells. And so when you embark on a low carbohydrate diet, you will deplete your muscle glycogen stores and therefore with it, you'll also remove a lot of that additional water or fluid.

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For every one gram of carbohydrate we store, we will hold an additional three to four grams of water. So by reducing carbohydrate stores, you then end up getting rid of the water. In addition to that, our baseline insulin levels drop and the kidneys respond to this by dumping out sodium. And sodium is critical to water balance. So if we don't have those additional electrolytes and water, then you can certainly be more dehydrated.

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than if you were just to be on a usual average intake of carbohydrates. So that is one other group that does need to think about their water intake. Having said that though, there is further research that if you've been consistently following a low carb diet, that in fact your body will hold on to more glycogen and it will resynthesize glycogen to the same extent as people on a higher carbohydrate diet and therefore you might not need.

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worry so much about your hydration status. Anyway, there's a lot you can go on about in there. Speaking of athletes, something else which I see out there that I'm not sure, I think there are definitely people questioning this notion that more carbohydrate is better in endurance exercise. Certainly the likes of Philip Prince who I've talked to on this podcast, and of course my mate Dan Clues, they've certainly raised questions as to whether more is better when it comes to carbohydrate intake. Now, of course,

13:05
I'm not here to say that there aren't some stellar performances on extremely high carbohydrate intake. The most recent example of this is David Roche or at Mountain Roche on Twitter and Instagram and he is a coach, he's a writer, he's a podcast host and he recently took the Leadville 100 mile record in an amazing time of 1526 and he reported that he took around about

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500 plus calories an hour. And so he was averaging, I believe he said around 120 grams an hour, but there were some hours he was pushing up to 120 grams. And when he was answering questions about this, he said that he only consumes like a huge amount of carbohydrate a few times during a training block, like those amounts that 120 to 140, though he will be around 90 grams of carbs an hour on all moderate intensity long runs.

14:04
And he also manages to drink about a liter of fluid all at once on his runs to prepare his stomach for volume, which is amazing. That is like certainly training your gut. But do the mere sort of mortal athletes like us, what effect will that have on our performance? And will we get this massive increase in performance if we just suddenly increase our carbohydrate? Well, I think it really depends on what your starting base is actually. And not just me, but others who have just mentioned the likes of

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and plos probably also say it. So the amount of carbohydrate generally recommended for the average punter in a running event, particularly because of the mechanical load on the gut, is around 50 to 60 grams of carbs an hour. To contrast that, we have Camille Heron, who captured 12 world records at Lululemon's further event, where she logged more than 900 kilometers in Lululemon's first six day race for women,

15:03
about 150 kilometers an hour. And her reported carbohydrate intake was much lower at around about 50 grams of carbs an hour because that is what she had discovered worked for her. So yeah, everyone is different. But if you look at the research, and Plouz did a great job of analyzing it in one of his Endura IQ blogs, it shows that while we can take on board a huge amount of carbohydrates, it might not.

15:30
necessarily enhance performance beyond that 90 grams of carbs an hour. There is accelerated breakdown of glycogen, increased risk of gastrointestinal distress, and suppression of fat oxidation. And in Plouz's blog, he shows that there's not necessarily an increase in performance beyond that 90 grams, even though studies have investigated the use of 110 grams and 120 grams of carbohydrate an hour. And

15:59
What the early research shows, as Blu writes about, is that we ingest our carbohydrates as glucose and maximise exogenous carbohydrate oxidation rates at around that 60 grams an hour. But when we get that mix of glucose and fructose, we can increase those exogenous carbohydrate oxidation rates up to about 90 grams of carbs an hour. This is because fructose and glucose are moved across the gut using different transport proteins.

16:28
If you have more glucose than that 60 grams an hour, that would actually back up in the gut and that would create some sort of GI distress. Some of the research looking at those higher rates of carbohydrate, those 120 grams of carbs an hour, show that we don't actually get any further glycogen savings when ingesting carbohydrates at those really high rates. And all of that extra exogenous carbohydrate oxidation will just displace fat oxidation.

16:56
meaning that we are burning through our glycogen stores at the same time, whether we're ingesting carbs at 90 or 120 grams of carbs an hour. And there's research from 2018 that suggests that increasing carbohydrate ingestion above that 90 grams an hour, not only fails to preserve glycogen, it might stimulate its breakdown, which clearly isn't something that we want to encourage. So.

17:22
He doesn't think that there's any convincing results that more is better with regards to carbohydrate intake, although you've got the likes of David Roche who is out there absolutely smashing it and doing amazingly on those super high intakes. So I think that individual results will vary. And what makes a super elite athlete like the likes of David Roche is in fact, there's probably something quite special about him. The fact that he is that elite type athlete.

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that he can push his body to those extremes, that he can take the record in the Leadville 100 mile race, that probably means it's hard to compare his results and his training and his nutrition plan in a way that's sort of helpful for us sort of mere mortals. So I just think that's really something worth pointing out. And hey, you guys know how I feel about super high carbohydrate intake. It's just not good for your health long-term. And as a middle-aged athlete, as many of you might be,

18:19
Do you really want to go down that path of having to rely on so much carbohydrate in order to perform? When instead you could just get fat adapted and rely less on carbohydrate. Anyway, moving on from that, one other critique which I'd just like to share with you is the idea that a pound of fat equals 3500 calories and therefore in order to lose a pound of fat which is close to 500 grams, you need to eat 3500 calories less across the course of a week.

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or burn 3,500 calories more across the course of a week, thus providing that deficit to enable you to lose a pound of fat. The 3,500 calorie rule dates back to a study published in 1958 by a Dr. Max Wyschnowski who estimated that a pound of body fat contains approximately 3,500 calories. This was based on the assumption that body fat is about 87% lipid,

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And since one gram of lipid contains approximately nine calories, a pound of fat tissue, just 454 grams, contains about 3500 calories. However, this doesn't actually stack up. And the reason why is that the human body doesn't operate in a static state. Energy expenditure changes with activity level, muscle mass, and even the type of food consumed. For instance...

19:41
Proteins require more energy to digest than fats or carbohydrates, which would potentially affect the net calorie balance. And of course, that then brings up the thermic effect of food, because different foods have different thermic effects. So proteins have a higher TEF, as I just mentioned, compared to fat and carbs, meaning that a portion of calories from proteins are used in digestion, absorption, and disposable of ingested nutrients.

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which isn't accounted for in the simple 3500 calorie model. Not only that, protein muscle synthesis is an energetically costly process which does burn more calories. So for every 100 calories of protein you eat, you only really use about seven or have 70 of them left over once you take into consideration all of those other pathways I just mentioned. With carbohydrate, for every 100 calories of carbohydrate,

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It just requires six calories in order to digest and absorb and get rid of. And for fat, every 100 calories of fat that you ingest, 99 of them are left available because it takes just one calorie in order to store fat away. Of course, having said that, maybe I just need to go and check my numbers there because these might just be numbers that I've heard from a guru and might not be true. So you check that as well, but I'm pretty sure that actually holds up.

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This simple 3500 calorie model also doesn't hold up because of exercise efficiency and muscle gain. When people start exercising they might initially burn more calories but over time the body can become more efficient at the same exercise so you will burn fewer calories for the same activity which is awesome but just not for fat loss. Additionally if exercise leads to muscle gain this can increase resting metabolic rate.

21:32
So that will also complicate this simple fat loss calculation because muscle takes up less space than fat. Hormones like insulin, cortisol, thyroid hormones, and others play significant roles in fat storage and metabolism. And you've got medical conditions like hypothyroidism, which can significantly slow down metabolism, making weight loss more challenging despite that calorie deficit. Some theories also suggest that the body has a set point body weight, which it tries to maintain.

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And when you lose weight, your body might fight to regain it through various mechanisms like increased hunger or reduced energy expenditure. So what does that mean? It means that simply by creating a 500 calorie deficit a day across seven days will not result in a linear fat loss effort. And people, I think they understand this, but when you're emotionally tied to a number on a scale and seeing it go down and you're in control, quote unquote,

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of what's going in, it can be difficult when you don't see the expected physiological response on the scales. So that's just a few things that people believe that don't stack up if you look at the literature. So zone two training does not stimulate mitochondria or biogenesis, neither does fasting. There's no science to support that we need eight glasses of water a day. More isn't always better when it comes to carbohydrate for the athlete.

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And a simple 500 calorie deficit a day equating to 3500 calories in a week will not result in a pound of body fat loss when you are trying to lose weight. So anyway, a few things. I'm sure you've got some that you can absolutely flick me a message on and I would love to hear from you because it's quite fun to go and look at all this stuff. So you can catch me over on Instagram, Twitter or threads @mikkiwilliden. Facebook.

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@mikkiwillidennutrition or head to my website mikkiwilliden.com and sign up to my unlocking metabolic mastery scientific approach to fat loss that's sustainable. It's my webinar and it's occurring on Wednesday the 18th of September at both 1pm and 7pm. For those of you who can't make it at lunch, come after work, after dinner, eat your dinner while we're talking about it.

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I'll have all the latest stuff. And I promise you that is absolutely researched to the nth degree and is solidly based on science and clinical knowledge. So we'd love to see you there. Pop a link in the show notes too. All right, team, have the best week. See you later.