[Transcript] – Good Carbs, Bad Carbs, High Carbs, Low Carbs & More: Clearing Up Carbohydrate Confusion With Dr. Michael Ruscio.

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Podcast from https://bengreenfieldfitness.com/2017/06/good-carbs-bad-carbs-high-carbs-low-carbs-more-clearing-up-carbohydrate-confusion-with-dr-michael-ruscio/

[00:00] Introduction/BiOptimizers

[01:45] Organifi Green Juice

[04:39] Dr. Michael Ruscio

[08:27] Good Carbs and Bad Carbs

[13:17] Food Allergy Testing

[20:20] Microbiota and Carb Intake

[34:56] Quick Commercial Break/Four Sigmatic

[36:18] Quip

[37:44] Continuation

[40:54] Thyroid Damage and Low Carb Diets

[51:57] How Low Low Carb Is

[53:38] Carbohydrates and Hunger

[56:20] Artificial Sweeteners

[1:04:45] Carb Intake and Testosterone Levels

[1:11:07] End of Podcast

Ben:  Good carbs, bad carbs, high carb, low carb.  Today's podcast sounds like a Dr. Seuss book, but that's just the way things roll.  So get ready for an episode with Dr. Michael Ruscio.

Before we bounce into that, this episode is brought to you by BiOptimizers.  BiOptimizers may sound like a techie name, but it's pretty simple.  What BiOptimizers does is they allow you to crank muscle gains, and recovery, and your anabolic state to new heights by flooding your muscles with amino acids without actually increasing your protein intake by a single gram.  So you don't have to actually stuff more steak into your gaping maw.  These are some of the most complete and advanced digestive enzymes that you'll find anywhere, and what they do is they combine them with something called P3-OM, which is the most potent protein digesting probiotic in the world.  So it's a one-two punch combo that gives you the ability to be able to process and break down proteins extremely efficiently.  And this is a very unique approach.  I've had these guys in the show before, they’re a biohacker and a bodybuilder, the two guys that make this stuff, and it's really cool.  You get a 10% discount on the combination of MassZymes, which is the digestive enzyme part, and their P3-OM probiotic.  How, you ask?  Easy.  You go to bengreenfieldfitness.com/biopt.  That's bengreenfieldfitness.com/BIOPT.  That automatically gets you 10% off your order of MassZymes and this P3-OM probiotic.

This podcast is also brought to you by something that has mint in it.  I don't know how much you use mint, but I've a bunch of mint pots out on my patio growing mint.  And mint helps to stop cravings, it soothes indigestion, it assists in sleep.  I'm sure that today's podcast guest, Dr. Michael Ruscio, who is an expert in all things gut, probably swears by mint.  Anyways though, mint is just one component along with things like chlorella, moringa, spirulina, beets, matcha green tea, wheat grass, ashwagandha, turmeric, lemon, coconut water.  It's all in this gently dried superfood powder called Organifi.  With an “I”, not a “Y”.  Organifi Green Juice Powder.  No mess, no cleanup, you don't have to chop up all the mint and pulverize it.  It just all comes gently powdered.  And you get a 20% discount off of this green juice.  You go to bengreenfieldfitness.com/organifi.  That's bengreenfieldfitness.com/organifi, with an “I”, and use discount code Ben to get 20% off.  So that all being said, now you know about your green powder and how to digest your proteins, let's go learn how much carb to eat, or not to eat, as the case may be.  Sit back and enjoy this episode with Dr. Michael Ruscio.

In this episode of The Ben Greenfield Fitness Show:

“There's a geographic explanation to this also when we look at hunter gatherers populations worldwide.  When you're at or around the equator from 0 to 30 degrees latitude, you tend to have a high carbohydrate, lower fat diet.”  “We have systematic reviews with meta-analyses looking at both metabolic syndrome and also separately at weight loss, and they do show that all healthy diets are healthful compared to a standard American diet.  When we look comparatively, the diets that have a slight edge are usually lower carb diets.”

Ben:  Hey, folks.  What's up?  It's Ben Greenfield, and that is a soda.  I figured I'd drink a soda because today we're talking all about carbohydrates.  But fear not.  This is one of those stevia flavored sodas, so I think I'll be okay.  Although we may bring up artificial sweeteners in today's episode and find out if I am going to get some serious metabolic downstream effects from drinking this thing.  My guest on today's show knows a lot about downstream effects of things that you put into your gaping maw.  His name is Dr. Michael Ruscio.  I've been on his podcasts a couple of times.  What's the name of your podcast again, Michael?

Dr. Ruscio:  It's “Dr. Ruscio Radio“.

Ben:  Of course it is.  Because your name is Dr. Michael Ruscio.  Not only have Dr. Michael Ruscio and I engaged in some pretty epic arm wrestling competitions at Paleo f(x) in Austin, Texas, where we're both headed to at the time of this recording, like tomorrow.  But Dr. Ruscio was also on the podcast episode called “Why Healthy People Get Broken Guts And What You Can Do About It”.  And in that chat, we talked about everything from elemental diets, to why athletes and exercise enthusiasts actually are some of the people with the highest amount of gut issues, and how you can combat that overstressing of the gut with specific nutrients.  We talked about cleanses, and enemas, and detoxing, and mistakes people make there.  We talked about actual anatomical damage to things like valves that pass through your gut and kind of like if you could test anything and everything going on in your gut, what tests you actually should get.

Now, that episode was fascinating.  I'm going to link to it in the show notes for this episode, which you can grab if you go to bengreenfieldfitness.com/gut2.  That's bengreenfieldfitness.com/gut2 because today, on this number two podcast, see what I did there, Dr. Ruscio is back.  We're going to talking about the latest research on carbohydrates and the gut.  He has a ton of research and reams that he's been sending over to me.  He's one of those chaps who bombards my inbox every now and again with cool studies, studies that I actually read and pay attention to 'cause he really is on top of things.  He's a functional medicine practitioner, he's a researcher, he's an author, he consults clients in the Bay Area and also remotely all over the country, he speaks all over the place, winds up at a lot of the same events I'm at, like Paleo f(x) and The Ancestral Health Symposium.  And he also collaborates with a ton of different authorities in the health and wellness industry.  And by collaborates, what that means is we all send each other crazy research studies back and forth, and then engage in long e-mail chains about what's going on.  So Dr. Ruscio, in addition to thanking you for gumming up my e-mail inbox, thank you for coming on the show, man.

Dr. Ruscio:  Thanks for having me back and thanks for actually reading the e-mails.  I appreciate that.

Ben:  You're welcome.  I actually do read those 'cause they're interesting.  And actually, speaking of interesting, I actually would like to start here if you are game, and that is a link that someone recently sent me to a post on Facebook.  And the post more or less was, it kind of like one of those if-it-fits-your-macros kind of post.  Meaning, that it really doesn't matter what you eat as long as it's in the percentage of macronutrients, the percentage of protein, fats, and carbohydrates that you're going after.  And it said, “All carbs get converted to glucose, so there's no such thing as bad carbs.”  So let's start there.  What do you think?  Is there a consensus regarding the role of carbs?  Is there such a thing as like a good carb or a bad carb?

Dr. Ruscio:  Well that statement's pretty silly.  I mean I think anyone with a decent level of education can pick that apart pretty easily.  Probably the most notable is the glycaemic index or the glycaemic load in terms of how quickly carbohydrates get converted to glucose.  So yeah, I mean just there you have a huge counter-argument to that point, which has been fairly well-validated that really important regarding carbohydrates is the glycaemic index, or the glycaemic load, or said simply, how quickly do these carbohydrates get converted to glucose.  ‘Cause the faster they get converted, the more potential they have for negative metabolic effects.  Which is why things like sodas an added sugars have been shown to be pretty awful for metabolism.  But when you consume your carbohydrates, or sugars, 'cause they do ultimately get converted to the same thing, but if you ingest them from fruits and vegetables that have fiber packed in with them and slow down the absorption of those sugar or those carbs, then they can actually show or garner metabolic benefits.

Ben:  Okay.  So let's put it this way. Like what if I've got a couple of carbohydrates that actually have similar glycaemic indexes?  Let's say, like, watermelon and white bread.  They're like in the 70's for glycaemic index.  So you could theoretically argue that both of those are carbs, they're both getting converted into glucose, they're both equal and there's no such thing as a good carb or a bad carb.

Dr. Ruscio:  So that would be a good counterpoint.  And then there's a couple other points that are important to keep in mind with all foods, but this definitely applies to carbs.  One is the allergenicity of the particular food.  And it's always a good idea to eat an anti-inflammatory or a diet that is low in allergens. So if someone does actually have the most extreme reaction to bread, as an example, celiac, or they have a more milder reaction, non-celiac gluten sensitivity, then even though the amount of sugar in the watermelon compared to the bread may be similar, the effect it has in the body from an immune reactivity standpoint is going to be vastly different.  And then there's one other component of this that's important, which is the fermentation potential of the carbohydrate.  And so for people that have things like IBS, or IBD, or bacterial overgrowths, they're going to want to be more careful with foods that have a lot of ability to feed bacteria because they may have preexisting bacterial overgrowths, and then eating foods that feed that even more may make them react negatively and feel worse.  So at face value, that may seem appealing.  But I think we can pretty easily pick that apart with a few of these counterarguments.  And they mainly are glycaemic index/glycaemic load, allergenicity or tolerability of the carbohydrate, and then also the fermentability of the carbohydrate.

Ben:  So you're saying, let's say peanuts, which are considered to have a pretty low glycaemic index, could spike my blood sugar more than say, brown rice if I happen to have an allergic reaction to peanuts or some kind of intolerance to say, like the lectins in peanuts or something like that, and that could cause some kind of like a cortisol response that would spike my blood sugar even though the glycaemic index is lower?

Dr. Ruscio:  Yes.  And you know who's been looking into this actually a lot is Robb Wolf, and he just wrote a book…

Ben:  Oh, yeah.  We talked about this on my show a little bit.

Dr. Ruscio:  Okay, yeah.  So he's on pretty deep into that, but yes, there's definitely more to it than just when you put this food in a bomb calorimeter, and burn it, and get a certain breakdown of the energy in there or the grams of carbohydrate, there's nothing more to that because there are other things that happen when you throw food into a biological system than just the mathematical read on the food.  So definitely.

Ben:  And when you even look at something like, let's say, popcorn versus watermelon, popcorn might not be fermentable, but watermelon might.  So if I have some kind of like a fructose intolerance, or like a FODMAP issue, watermelon could actually screw me while popcorn, with a very similar carbohydrate content, could be just fine.

Dr. Ruscio:  Precisely.  And I think this comes down to a pretty simple takeaway, which is learning to listen to your own body.  And if you notice certain foods sit well with you, then focus on those foods.  If you notice other foods don't seem to sit well with you, even if you read an article saying how great that given food is, if you've noticed it doesn't seem to sit well with you, then don't force yourself to eat that food.

Ben:  Before we move on, 'cause I want to ask about the microbiota and how that actually influences this, and whether people who have a digestive condition need to choose their carbohydrates differently or something of that nature, is there a particular food test, like a food intolerance or a food allergy test that you swear by or that you use in your practice most frequently?

Dr. Ruscio:  For allergy testing and intolerance testing, I really don't use much of those because we have some diet plans that give you a pretty good map or a pretty good listing of the most common food allergen and/or food intolerances.  So this might be, like the Paleo diet cuts out many allergens, the low FODMAP diet cuts out many of these carbs that can feed bacteria and be problematic for people.  So they can be much more economical and efficient to start there.  Also, some of the testing that can be used, for example breath testing to diagnose for dose malabsorption or lactose intolerance, it's recommended that that testing only be done after someone has been screened for small intestinal bacteria overgrowth according to the recently released North American Breath Testing consensus.

Ben:  Wait.  You mean get screened for small intestine bacterial overgrowth even before you do a breath test?

Dr. Ruscio:  Yes.

Ben:  And how would you get screened?

Dr. Ruscio:  So you still do a breath test, but there's a breath test for small intestinal bacterial overgrowth, and there are different breath test for fructose malabsorption and lactose intolerance.  And so before you jump to the fructose malabsorption or lactose intolerance breath testing, you should do the SIBO breath testing first because SIBO can cause a false positive on the fructose and lactose tests.

Ben:  Okay.  I got you.  So you do the SIBO breath test first, and if it winds up that you don't have something like small intestine bacterial overgrowth, which is where you swallow a whole bunch of sugar and you breathe into a tube multiple times over the course of a few hours, and it kind of like shows the rise in gases that the bacteria produce, if it shows that you don't have an issue there, then you could go on and say, test for something like a food intolerance to something like fructose or something along those lines, like a different breath test?

Dr. Ruscio:  Exactly.  Yeah.  So we save some of those tests for more of like a secondary or tertiary intervention.  And then with certain food allergies, many people will, just through elimination and then reintroduction, be able to sort that out.  And that's why there is debate in the research literature, but there are certainly many other researchers that conclude that the best test for food allergies is to eliminate and then reintroduce rather than perform tests.  And there are some tests that show a mild amount of utility in being able to more quickly pinpoint your food allergies when using food allergy testing, but when you weigh that against the fact that you're looking at at least like $350 to get started, if not a thousand dollars if you're doing a really fancy food allergy test and you have to maybe do that a couple times, when someone could save potentially a thousand to a few thousand dollars by just following an elimination-reintroduction diet plan for free, you make a pretty easy argument for doing it without any testing.

Ben:  Now what about this concept of a Cyrex panel, which is one that I've recommended and certainly taken myself in the past.  The idea being that that's a little bit more of an advanced clinical test that looks at a whole variety of antibody arrays for thyroid, and gluten, and other food associated autoimmunities, or even neurodisregulation related to different types of food intake.  And from what I understand, they kind of surpassed the standards of a lot of these other tests like the ELISA test, or the ALTCAT test, like a lot of these blood spot tests, you can get very few false positive results.  Do you have any take on that particular test, the Cyrex test?

Dr. Ruscio:  Yeah, I'm certainly open to the Cyrex test, but it's not something that I've used a lot just because I try to continually weed down to only the most necessary tests.  And there's kind of two diametrically opposed ways you can look at this when you're in clinical practice, which is “what more can I do”, and that can lead to well-intentioned, but oftentimes a large amount of testing.  The other way you can look at this is “what are the absolutely most critical tests that have the highest impact”, and that's a question I keep asking myself.  And so I see predominantly gut cases, gut and thyroid are my two areas of focus, my primary focus is gut, and I see patients that have been to many other doctors and not gotten great results, and I see many kind of advance cases.  And generally speaking, we get, I think, pretty excellent results and I haven't performed a food allergy test now in probably three years.

So you can make a case for them, but I think you can also make a case against them.  And the case against them is they don't provide us, I think, absolutely crucial information and they're fairly costly.  And the reason I say they don't provide crucial information is because oftentimes what you see on the food allergy tests is really just noise.  And when I say noise, I mean false food allergies that will improve as you improve one's gut health.  Also many of the results on the tests are things that are fairly easily ascertained when someone performs an elimination and then a reintroduction.  Not to mention that there's more to if the food is good or bad for your gut than just immune reactivity.  There are other things like the fermentability that we've talked about.

Ben:  Good point.

Dr. Ruscio:  Yeah.  And also some people are histamine sensitive and you don't see that on these tests.  And then there's also cooked versus raw foods, so Cyrex released a panel that included cooked versus raw foods because a study found that the food allergy test scores differently if it's a cooked food versus a raw food, so now you're looking at like a thousand dollars plus for a food allergy panel.  So for all these reasons, I'm open to using those tests.  I haven't found that to be absolutely necessary and I've been able to get great results without having to spend a thousand or so dollars on a food allergy test and focused on other things that I think are more important.

Ben:  That's actually a really good way to look at things.  I hadn't really considered the fact that if you, let's say you run into a lot of issues when you eat, well let's say watermelon.  I am apparently obsessed with watermelon today.  And you don't have a food allergy to watermelon, I don't think many people do, but you could still have a lot of fermentation, and gas, and bloating from the fructose sugars in watermelon and wonder why you feel like crap even if the watermelon isn't in the list of things that you posted on your refrigerator that you shouldn't eat.  So yeah, I think it is a little bit more complex than food allergy testing.  I agree.

You mentioned to me about this idea behind the microbiota and how when we look at like how many carbs you actually can, let's say like get away with eating, or how the microbiota influences whether or not your level of carbohydrate intake is appropriate or not, how does the microbiota influence that?  You'd think that people who have like a poor level of bacterial balance could feed their healthy bacteria with carbohydrates, and then that might help them out.  Like what's the deal with the microbiota and how that influences this?

Dr. Ruscio:  And how that influences digestive symptoms, or metabolism, or…?

Ben:  Yeah.  Well specifically when it comes to the microbiota, how it might influence whether or not you should say, eat more carbohydrates or how the microbiota influences the actual dietary choices you should make.

Dr. Ruscio:  It's a very interesting question, and there is a lot of research occurring, of course, in the microbiota right now, in the field of microbiota, and a lot of the research is preclinical.  And that's very important to keep in mind because what oftentimes happens in an area where there's increased interest is you have, early stage research is very interesting but not necessarily ready to be converted into clinical recommendations, but that doesn't stop people from trying to convert these early interesting academic findings into clinical recommendations.  So people really have to be, I think, a bit guarded with the information they get on the internet and about the microbiota because a lot of it is super speculative and it's way pre-clinical, and so it's foster that out there as a qualifier.  Now there have been a couple of studies, I think only one that was really noteworthy, maybe two that have shown a microbiota test could predict somebody's preferential diet.  One was looking at essentially glycemic response and helping to steer the types of carbs from a blood sugar regulation perspective, and the other was looking at kind of your FODMAP tolerance based upon a microbiota test.  Now the first test isn't available…

Ben:  FODMAP being like your fermentable fructans, oligosaccharides, wait I can do this, disaccharides, monosaccharides, and polyols?

Dr. Ruscio:  You got it, yes.

Ben:  Boom.

Dr. Ruscio:  So, yeah.  The one test, or the second test was helping people know what type of fermentable FODMAP-type foods they could or could not eat.  The first test I don't believe is available in clinical practice yet 'cause it was a group of researchers.  And I'm not even sure on the second test.  So that's kind of where some of these things are.  The most clinical information we have, some of the tests that have been used aren't even available in clinical practice yet.  So I don't have a stool test or a breath test that can tell you what to eat.  But there is I think a fairly straightforward way of kind of navigating through this, which is not looking at it from the perspective of “let me find out what my microbiota looks like, and then that will tell me what to eat”, but rather looking at this like a hierarchial process that you work through, and that will help you arrive at the best combination of dietary and lifestyle factors that will keep your microbiota as healthy as it can be.  ‘Cause I think we're making a little bit of a mistake right now in this area of research thinking that the microbiota is the ultimate dictator of our health, and so all of our health is going to be influenced by our microbiota.  So if we can just manipulate our microbiota we can improve our health.  But I think actually the opposite is true where we have to create a hospitable environment for a healthy microbiota, and once we do that, a healthy microbiota will flourish and then we can reap the health benefits from that.

Ben:  Yeah.  But what I'm basically asking is for your bacteria, I mean they need some amount of carbs to actually flourish, like prebiotics, and fiber, and things along those lines.  How would you, as many people do, eat a low carbohydrate diet and still have good bacterial balance.  And one reason I ask this question, dude, is because I look at some of the gut tests and some of the bacterial balance tests of people who have done like a three-day stool test and who are doing a lot of fatty coffee, and doing like a high fat, very low carbohydrate, like less than 40 grams of carbs a day, kind of strict ketogenic diet.  And in many cases you see a low amount of gut bacteria, or almost kind of a little bit of a wasteland when it comes to the gut microbiota.  Like how do you actually feed your gut if you're not doing many of these carbohydrates?

Dr. Ruscio:  Right.  Great point.  I was working my way there maybe in a bit of a circuitous fashion.  But using that analogy and building on that analogy of creating a hospitable environment for your microbiota, if we think of our body as the environment that houses the ecosystem of the microbiota, we can kind of think of it like this: not every geographic ecosystem requires the same amount of rain and sun.  You have a rain forest, requires a lot of rain.  You have an arid, more desert-like climate of Southern California, and if you put the amount of rainfall from a rainforest into Southern California's arid climate, you would cause mud slides, death, and some major catastrophes.  So it's a mistake to think that every ecosystem requires the same amount of rain, and that could be analogous to carbohydrate intake.

Not every ecosystem requires the same amount of rain or carbohydrates.  And that's really important to mention.  And that helps us fundamentally answer this question, which is why do some people who are eating diets that don't feed their gut bacteria seem to be doing pretty well from an overall health perspective?  It's because we can't measure, we can't say that this one microbiota is the healthy microbiota everyone needs to strive for, but rather understand that just like there are different ecosystems, there are different microbiotas that are going to be better.  And there's a geographic explanation to this also.  When we look at hunter-gatherer populations worldwide, when you're at or around the equator, from 0 to 30 degrees latitude, you would tend to have a high carbohydrate, lower fat diet.

Ben:  You mean, that's what the people who live in those areas eat?  Or that's what anybody who happens to be visiting those areas on vacation thrive on?

Dr. Ruscio:  No.  Thank you for clarifying.  So when we look at the way unaltered hunter-gatherer bands would eat in those areas, before the advent of grocery stores and all that, so for people who have genic lineages from these different areas, they have a higher probability of doing better on this type of diet.  So if your genes, if you're Ecuadorian, let's say, descent, then you may do better on a higher carb, lower fat diet.  If your genes evolved in the Mediterranean region, 30 to 40 degrees latitude, then you'd do better on kind of this moderate carb diet, just like the Mediterranean diet is.  And then if you're over 40 degrees, let's say you're from Ireland or in these Northern European areas, then you more likely will do better on a little bit of a lower carb diet.  And we see that same thing happen clinically where when we actually look at the clinical research, we see that not everyone does well on a diet that feeds bacteria.

In fact, I would argue, and this is an argument based upon the scientific literature, when you look at, let's say some of the highest level science looking at what the best type of diet is for those with metabolic syndrome or those with weight loss, we have systematic reviews with meta-analyses looking at both metabolic syndrome and also separately at weight loss, and they do show that while all healthy diets are helpful compared to a standard American diet, when we look comparatively, the diets that have a slight edge are usually lower carb diets.  So if you really needed to feed your microbiota, how is it that we see the highest level science showing a slight edge for weight loss and metabolic syndrome by using diets that actually tend to starve slightly your microbiota?  So I think that we have fundamentally have to look differently at this question of…

Ben:  Do those diets really starve the microbiota though?  I mean have they tested the microbiota and found that the type of diets you mention, like the ones farther away from the equator where people aren't eating as many carbohydrates, do those actually stave the microbiota?  I mean playing devil's advocate here, are those low carbohydrate diets or just like kind of low net carbohydrate diets where people are still getting fiber and things that feed their gut from let's say kale, or sauerkraut, or kimchi, or I don't know what they Scotland, haggis, whatever.  Like is this stuff still feeding the microbiota?  Like have they actually looked at the microbiota itself and said, “Oh, hey.  It turns out that people who are eating low carbohydrate diets in some of these areas that maybe aren't doing what's trendy in America right now for low carbohydrate diets, coconut oil and butter, that in a more like ancestral low carbohydrate type of approach, people actually do have healthy microbiota?”

Ben:  Yeah.  Great question.  That's the same question that I've asked myself as I've been kind of parsing through this literature because I never want to take these things at face value.  I also make sure that we're really thinking critically through these questions.  And while we don't have this data for every study that looks at a low carb diet compared like a vegetarian diet, from the data that we do have we do tend to see, “Yes, these diets do tend to either starve the microbiota or are documented to be lower in fiber and carbohydrates, and fiber is probably the main ingredient that is going to feed the microbiota.”  So yes, there have been studies that have looked at these diets, they've done comparative diet trials, and they've shown either the lower carb and, or the Paleo diet is slightly lower in fiber compared to a more typical Mediterranean-type diet or even a more low fat, high carb diet like Pritikin or Ornish, if those are the diets that are being studied.  And we also have some studies, and these ones are really fascinating, that have broken down the carbohydrate content from high, to moderate, to low, and they've shown a progressive dwindling of the microbiota as you go from high, to moderate, to low.  The lower you go, the more the microbiota dwindles.  And actually when they tip over from non-significant to significant changes in the microbiota, so when you go from moderate or if you start to see a significant drop off in the microbiota, you also start to see a significant improvement in weight loss.

Ben:  When you go from moderate to lower carbohydrate, microbiota goes down but so does weight loss?

Dr. Ruscio:  Precisely.

Ben:  Interesting.  It sounds to me like it's kind of like an unsolved mystery so far that someone would have a decrease in say, like the health or the diversity of their microbiota and still lose weight.  Or are we looking at a scenario where maybe you're losing weight, but it's not healthy weight loss?  Like what if you lose weight, but you aren't producing neurotransmitters 'cause your bacterial balance is low, or your immune system suffers, or you develop leaky gut, or something like that?  I mean are we looking at this the same way as we would look at say, well there's a lot of unhealthy triathletes and marathoners out there who are really skinny and who have lost weight, but it's not necessarily like healthy weight loss in many cases.

Dr. Ruscio:  I think there is some error to fundamental premises that have been established.  And one premise is that you have to feed your gut bacteria in order to be healthy.  And it's looking at some of the research that's coming out of, let's say Africa, hunter-gatherer bands, modern day that eat a lot of carbs and a lot of fiber, that's skewing the data.  ‘Cause when you look at the sampling of modern day hunter-gatherers, it's all in highly equitorial regions.  Not only that, but we don't know if the diversity is the cause of the disease or if it's an adaptation to the disease.  I have been making the argument for a while, and you're starting to see more and more of this published in the research literature that the decreased diversity is actually an adaptation because of potentially a non-healthy immune system in the gut.  And so the immune system can't handle a very robust microbiota, and this might be why we see patients with IBS and IBD have a lower diversity.  But when we go to feed their microbiota with fiber and prebiotics, those patients oftentimes have negative reactions.  What's even more interesting is some studies have even shown that by doing something like an elemental diet, people will then see after the elemental diet an increase in diversity in their microbiota even though they…

Ben:  What's an elemental diet?

Dr. Ruscio:  An elemental diet is essentially a zero fiber liquid diet.  So that's really going to starve the microbiota.  But somehow after starving the microbiota, we see an increased diversity, maybe because you've calmed down the immune system in the gut and allowed a little bit better of a balance and the gut to flourish.  So I mean to zoom this way out, I think there's one important takeaway here and that is we're assuming that we have to feed our gut bacteria in order to be healthy, and I think that premise is fundamentally flawed.  Especially, to throw one more example in there, when look at some of the studies in IBS and IBD, we see that when we put patients on diets that starve the microbiota, like a low FODMAP diet, we see less inflammation and improve disease activity.  However, when we put them on either prebiotic supplements or high FODMAP diet, we see a worsening of disease activity.

Now not every study shows this.  Not every study with supplemental prebiotics or using high pre-biotic diets are bad.  But I think when we look at populations that have preexisting gut conditions, we see you have a higher chance of reacting negatively to fiber and prebiotics than you do responding positively to those.  And when combine that with the fact that some of these studies show improved weight loss on lower carb diets even though we see a slight decrease in the microbiota, I think we have to start asking some serious questions in terms of is this microbiota thing the next “it” thing, kind of like low carb diets were five to 10 years ago.  Probably not.  And we need to, I think, take a big breath and healthy step back and not obsess over feeding gut bacteria as an end-point for improving our health.

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Ben:  Hey, I want to interrupt today's show to tell you that no matter what kind of carbohydrates you consume, you should try this stuff called reishi.  Reishi is one of the ingredients that is in the sleep cake that I just wrote an article about in Men's Health M6agazine.  Reishi is one of the most relaxing compounds that you can put into your body, but it doesn't make you groggy after you take it, as you might get if you, say, smoke a joint.  Not that I endorse smoking a joint.  Reishi, and in particular this Reishi Elixir made by Four Sigmatic, is extremely relaxing and is packaged along with licorice root, star anise, peppermint, and stevia.  So it tastes really good and it has a lot of other goodies that come along with it.  Now reishi mushroom extract, along with all the other mushroom elixirs and mushroom spores that I absolutely adore, you can get 15% off of any of these mushroom extracts.  How?  You go to foursigmatic.com/greenfield.  That's FOURsigmatic.com/greenfield.  Use coupon code BenGreenfield.  I recommend one of the first things that you add to your cart are these reishi spores.  Extremely good medicine.

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Ben:  Now what if you were just taking a low carbohydrate diet, but you just make sure you take a probiotic and prebiotic?

Dr. Ruscio:  So there's something interesting.  Some probiotics actually kill bacteria.  To be truthful, they have been shown to increase bacterial diversity.  But I guess the point I'm trying to make is if you're eating a low carb diet and it's working for you, I wouldn't be overly concerned about having a potential negative effect on your microbiota because we do know that different regions around the world will eat lower carbohydrate diets, and I think right now we're seeing a bias in the literature that's just fiber, fiber, fiber, prebiotic, prebiotic, prebiotic, feed your bacteria, feed your bacteria, feed your bacteria, but I don't think that's totally founded.  So I would recommend someone always try to work toward the broadest diet possible, but there are many people who will find that they feel a lot better on a lower carb diet.  And that has been shown to partially kind of trim back the microbiota, and that's not necessarily a bad thing.  So yeah, I don't know if I'm being too [0:38:46] ______ with you there, but…

Ben:  It's really interesting.  So what it sounds like is basically, to kind of wrap up this part of the discussion, if you're eating a low carbohydrate diet and you're seeing some issues with your microbiota, or you're concerned that you might not be feeding your microbiota, it may not be as important as you think, especially when it comes to weight loss.  And that when it comes to restricting carbohydrates, in particular restricting fermentable carbohydrates like FODMAPs, seems to result in less inflammation and better weight loss despite the fact that you might not be, say, “feeding your bacteria” quite so much.

Dr. Ruscio:  Yes.

Ben:  Interesting.

Dr. Ruscio:  Yeah.  I think that's well-said.  And maybe just to try to reiterate that one more time for people to paint it simply.  If you're finding you feel better on a low carb diet, you should not be concerned about that diet starving your microbiota.  If you feel better on a high carb diet, then great.  But there is a, I think, erroneous bias toward needing to feed your gut bacteria, which does not work for all people.  It's not a problem for many people and it certainly isn't a bad idea, but if you engage in approaches that feed your gut bacteria, high fiber diets, high prebiotic diets, prebiotic supplementation, fiber supplementation, higher carb diet, and you feel worse, then don't feel pigeonholed into needing eat that diet because we have an overwhelming amount of clinical data, and I would argue the clinical data that shows, or that looks at diets that starve bacteria or clinical interventions that are anti-bacterial shows an overall better benefit clinically than these studies looking at diets that feed bacteria or the interventions that feed bacteria.

Ben:  Okay.  Got it.  That makes sense.  Now what about the elephant in the room here, two elephants in the room that I get a lot of questions about: thyroid and testosterone with carbohydrate restriction.  Does a low carb diet actually cause damage to your thyroid?  Is there actually evidence for that?

Dr. Ruscio:  Another great question.  And we had, and I think I sent you the links for these, we've done a few pretty…

Ben:  Yeah.  You sent me a ton of studies.  And for those of you listening in, go to bengreenfieldfitness.com/gut2 and I'll put all the studies in the show notes.

Dr. Ruscio:  Right.  And so for people that really want to get into the particulars, we've kind of gone through and combed through the literature on this.  But there's a few important things.  So when people say it damages your thyroid, we have to kind of define what that means 'cause that's a really vague term.  And I think there are two things that people are meaning sometimes when they say that.  Either a) you're feeling thyroid autoimmunity, meaning the Hashimoto's process in most people, or more Graves' in a small number if they have hyperthyroidism.  So are you feeling autoimmune damage process to the thyroid, or are you causing a negative impact in your metabolism by skewing the levels of your thyroid hormones?

So let's look at these one at a time.  Thyroid autoimmunity.  There are no studies to my knowledge, and this is after a pretty exhaustive review of the literature on this, showing that a low carbohydrate diet worsens in any way thyroid autoimmunity.  There has been one study that actually has…

Ben:  Can I interrupt real quick?  When you say low carbohydrate diet, are you saying that that's the same thing as a ketogenic diet?

Dr. Ruscio:  Well, it's tough because not all the literature is going to delineate between a low carbohydrate diet that's ketogenic.  But looking at both types of studies, either just lower carb diets maybe around a hundred grams or a ketogenic diet, so maybe 30, 50, or below, neither one of those have shown, have been documented to cause a worsening of thyroid autoimmunity.  Albeit there's not a lot of studies I have looked closely at that, but we do have one study that did look at that, and what this study did was it put people on an adhoc low carb diet, adhoc just means “here's some general recommendations, do your best to comply with these”.  And what ended up happening in this group is they ate roughly around 200 grams of carbs a day, which was a reduction from where they were previously.  They were instructed to eat large leafy greens, and vegetables, and lean meats, and also to avoid eggs, legumes, dairy products, bread, pastas, fruits, and rice.  So it was kind of like a paleo diet really.  And these people were again using around 200 grams of carbohydrate per day, which was a lowering from their previous diet.  And in this group, there was a 44% reduction in thyroid antibodies.  And there was also a better improvement in the group that went on this diet compared to the healthy reference diet.

Ben:  That's kind of interesting.  You think that the thyroid antibodies went down in response to a low carbohydrate diet because the carbohydrate sources actually had things that were influencing the thyroid antibodies, that were increasing the thyroid antibodies.  Like maybe people were eating a lot of wheat, or what would be another allergenic high carbohydrate source, Michael?

Dr. Ruscio:  Well, wheat would be one.  Dairy could be another 'cause a lot of dairy has a fair amount of carbohydrate.  But here's something else that's really interesting because I think this next point hints that it may have gone beyond just like the gluten that these people cut out in the grains, which is they showed that 83% of the patients with thyroid autoimmunity also showed that they had lactose malabsorption on a breath test.  And so this hints at the degree of carbohydrate malabsorption and the inability to tolerate fermentable carbs, like the fermentable dairy in this case.  So what this indicates is it may not just be the fact these people are going grain-free, but then these people were also showing carbohydrate malabsorptions, specifically for lactose.  And avoiding the carbs that these people can't digest well may have also contributed to the improvement in thyroid autoimmunity.

Ben:  Okay.  Interesting.  Now I personally saw some thyroid dysregulation when I was doing a full ketogenic diet, but I was also racing Ironman triathlon, and I was doing a lot of really hard exercise combined with very low carbohydrate intake.  And I don't, to my knowledge, know of many studies that have actually looked into population doing that kind of masochistic mumbo jumbo as opposed to the study you just talked about.

Dr. Ruscio:  Right.  So that kind of speaks to the other component of this, which is not the thyroid autoimmunity, but then the thyroid hormone metabolism, right.  Looking at your TSH, your T4, and your T3, 'cause that's the other side of this.  So I think it’s safe to say that a low carb diet is not going to damage your thyroid in the sense that it's going to fuel thyroid autoimmunity, which is really the prominent damaging factor for the thyroid.  You can have skewed levels of T4 and T3, but that's not damaging your thyroid, that's just affecting the metabolism of the thyroid hormones.  So two items here: thyroid immunity, one.  We've already checked that box.  It doesn't seem that low carb diets negatively impact thyroid autoimmunity, a.k.a. damage your thyroid.  But the second box, the second question is do low carb diets cause problems with thyroid hormone metabolism?  Meaning will you not produce enough T4, or more importantly will you not produce, will you not convert enough T4 into T3.  And so this is where things get a little bit interesting because you do see changes in TSH levels and also the conversion of T4 into T3, to put it somewhat loosely, when people go on low carb diets.

But the question is is that a negative change or is that a reaction to the change of substrate availability in the body?  And what some of the research has shown is that as long as you don't go too low carb for too long, so ketogenic may fall into this, and I believe they say that there is a caloric ceiling where as long as you're above the ceiling, the negative metabolic consequences of a low carb or low calorie diet are minimal.  And I believe I might be wrong here, but I believe it was 800 calories.  It was either 800 or 1200.  I can't quite recall, but it's in the notes that I sent you.  So as long as you're not going low calorie and low carb, the negative reactions are minimal.  You will sometimes…

Ben:  Yeah.  It was about 800 calories of carbs per day.

Dr. Ruscio:  Right.  Okay.  As long as you're not going low calorie, meaning your calories are below either 800 or 1200, just going on memory for that one, and doing low carb with that, the risk of overt negative changes appears to be minimal.  But you do see an oscillation in some of these hormone metabolites like conversion of T4 to T3 when you go lower carb because that is kind of pushing you a little bit more into like a pseudo-fasting response and you do see metabolism shift when people are in the fasted state.  But the question is is this a bad thing?  Now it's not necessarily a bad thing as long as the dose and the duration is appropriate.

So if people are going dose or doing that for too long a duration, then they have potential for negative metabolic consequences globally that's not just independent of the thyroid.  It means you're essentially starving your body for too long, you're fasting your body for too long and too hard, and now you're experiencing negative metabolic consequences globally, including conversion of T4 to T3, but those people may also not sleep well, they may be irritable during the day.  So it's not just this thyroid-centric way of looking at it.  And there's one other study I just want to touch on really quickly, and this one it was really interesting.  It was entitled “Influence of a 10-Day Mimic Our Ancient Lifestyle on Anthropometrics and Parameters of Metabolism and Inflammation: The Study of Origin”.  Essentially, they had people follow a hunter-gatherer-type lifestyle for, I believe, it was a week, or two, or three.  It was a couple week intervention and…

Ben:  It was a 10-day.  I'm looking at the study.

Dr. Ruscio:  Okay.  Thank you.  So the interesting thing here was, to put it simply, people saw pretty much all their symptoms and their measurements improve in terms of they had better energy, that they were sleeping better, they had higher senses of subjective well-being, they lost weight, they lost body fat, but their levels of T3 actually looked a little bit worse.  So it's important to mention that just because we see a negative change in one lab value doesn't mean that negative change couldn't be occurring in someone who globally is looking much healthier.  So to tie this all in a bow, if you're going too low carb for too long, that may cause negative metabolic consequences of which may include a negative, or a decrease in your T3.  But the T3 isn't really the cause of the problem, the cause of the problem is you're going too low carb for too long for your metabolism.  And you'll want to just try to up your carbohydrate intake until you start feeling better and use how you feel as the gauge, and I would not recommend obsessing over your lab values.

Ben:  Okay.  So even if your TSH is increasing or your T3 is dropping, that doesn't necessarily mean you have a decreased metabolism or you're going to gain weight?

Dr. Ruscio:  Right.  As long as these things are happening within the reference range and you're feeling better while you're making these shifts…

Ben:  So if my TSH, say, goes from, like the reference range for TSH for example depends on who you ask.  For me I look for like 0.5 to 2.  But let's say I jump from like 0.7 to 1.5 because I've started a low carbohydrate diet.  That's not cause for concern.  What would be cause for concern is if it's like jetting way up around like five, or six, or something like that, and I'm at the same time feeling cold, and gaining weight, and I'm actually seeing actual issues as well as very high values that are outside of the normal range.

Dr. Ruscio:  Precisely.  Yes.  Yeah.  Make sure that we factor in how someone's feeling because oftentimes what you'll see is when people go on a lower carb diet they feel better globally and their metabolism and their body weight composition is improving, but their T3 may go down a little bit, but it's because they're going into a semi-fasted state on the low carbohydrate diet, which has a lot of utility.  And the lower T3 is just part of that fasted state that can be very good for your metabolism.

Ben:  Gotcha.  And by the way, just real quick, when you're saying low carb, I mean I kind of sort of asked you this earlier if it was the same thing as ketosis, and it sounds like there's definitely some differences, but when you talk about low carb, and you're talking about these studies, like for the average person about how low would low carb be?

Dr. Ruscio:  That's challenging because the studies don't always use the same definition.  But the way I would define it is if someone's going below a hundred grams per day, they're now going into more of like a very low carb diet.  If there are around 100 to 150, 100 to 175, maybe that's kind of low carb.  And then once you start getting to 175, 200, and above, that's kind of like a moderate carb.

Ben:  Okay.  Gotcha.  That makes sense.  Ketogenics in many cases for a lot of people who aren't active, like 20, 30, 50 like around in there.  So more carbohydrates than would be considered a ketogenic.  Now what about this idea, 'cause I was talking to somebody who I, handed them one of the energy bars that I'm personally working on, creating like this really healthy energy bar, and I've tested my post-prandial blood glucose after eating it and it's negligible.  It's a mix of like cacao nibs, and kanawa, which is similar to like baby quinoa, and a little bit of raw honey, and some coconut flakes, and chia seeds, and things along those lines, and they mention that it seems to be extremely high in carbohydrate and that it would make people fat, not necessarily because the bar has a lot of calories or a lot of carbohydrates, but because people would want to eat more carbohydrates and eat more food after eating the bar.  It would somehow produce this like incretin-based hormonal response that you wouldn't get if the bar were just, say, made out of MCT oil and collagen, let's say.  What's your take on that?  Like the idea that even small amounts of carbohydrates would somehow have that type of influence on the metabolism or on hunger?

Dr. Ruscio:  So are there artificial sweeteners in this bar or they're just naturally occurring carbohydrates?

Ben:  No, no.  Just naturally occurring carbohydrates, like from raw honey for example, or cacao nibs.

Dr. Ruscio:  I'm not inclined to think that that's true for most people except for the small subset of people that notice that once they start eating carbs, they can't stop.  And there's definitely some people that really gravitate toward low carb because if they have a little carb, they just can't stop eating.  So I think it would apply for them.  But as a general rule, saying that having some carbs in a bar is going to propel someone into overeating, I don't know where that comes from.  And by the way, Ben, I just want to really take to say to make fun of myself because in the study of that title I just read, it says “10-Day”. And so the hunter-gatherer study, “Influence of A 10-Day Mimic”, and I wasn't sure how long the study was.  So I'm not maybe as smart as I try to come off sometimes.

Ben:  That's okay.  You're still pretty good arm wrestling, so I'll forgive you.  Yeah, I looked at a recent study, it just came out a couple of weeks ago, and the title of the study is “Changes In Food Cravings During Dietary Carbohydrate Restriction”.  And they did find that people who ate a low carbohydrate diet had fewer food cravings, especially for sweet food.  And they also lost weight, and that's not surprising.  When you cut out starchy foods you're going to lose, even in a short term study, you'll some salt, you'll lose some water, you'll lose some glycogen weight.  But ultimately when you look at the actual low carb diet, it was more like what you were just talking about, like a hundred grams or up around, I think there was like 1200 calories a day, and it was a good, like I believe 15, 20% of that was carbohydrate.

So they were eating relatively, it wasn't like they were eating a ketogenic diet where they were completely avoiding carbohydrates.  It was more like they weren't eating the typical standard American diet, 60 to 70% of their intake from carbohydrate.  I mean they were taking about 50 to 60% of their energy from fat, about 20 to 30 from protein, and I believe in the range of like you know 10 to 20-ish from carbohydrate.

And so I don't think that you necessarily need to get rid of carbohydrates completely or forgo the energy bar that has 10 grams of carbohydrate in it so that you don't get cravings for sweet food.  That's my take when I look at this study, even though there's definitely, there appears to be an advantage to dietary carbohydrate restriction when it comes to food cravings later on.  But what about this deal?  What about this little can of soda in my hands with the stevia in it and other cans of soda that have aspartame, or acesulfame potassium, or these other artificial sweeteners?  What's your take on artificial sweeteners?

Dr. Ruscio:  Well I totally agree with what you said, Ben, which is we don't, to go lower carb doesn't mean we have to be crazy about it and go all the way to ketogenic.  And I think we get a lot of utility and a lot of gain out of just simply restricting some of these carb-dense inflammatory foods like some of the grains, and of course anything with added sugar, and just focus on a whole foods diet that your carbs mainly comes from vegetables, fruits, nuts, and seeds, and keep it that simple.  And we don't have necessarily go to these crazy extremes.  So I totally agree with you on that.

And then regarding artificial sweeteners, gosh, there's so much to say here.  Maybe I'll lead with like the simple takeaway, which is the research on artificial sweeteners has really not shown any conclusive benefit in terms of preventing weight gain, preventing high blood sugar, or causing weight loss, or leading to things like lower blood sugar, or improvements in metabolism.  There's really not any conclusive data to show benefit.  There is some data that is suggestive of potential detriment.  It's not an airtight case, but there is data suggesting potential detriment metabolically from using artificial sweeteners.  So because no clear benefit has been shown and there is some suggestion of detriment, I think people should really exercise caution when using artificial sweeteners and I think you're better off avoiding artificial sweeteners for the most part.  I mean occasional use isn't going to be a big deal.  But opting for natural sweeteners like juices, or honey, or even a little bit of sugar instead of using artificial sweeteners.

Ben:  What about stevia?

Dr. Ruscio:  We don't know as much about stevia.  You can make the argument that it's natural and that may be better.  And we had Susie Swithers on the podcast a while back, she's a researcher who is predominantly looking into artificial sweeteners.  And her comment was until proven otherwise, we should probably assume that stevia follows the same rules as some of the other sweeteners just to be on the side of caution because we really don't know.

Ben:  I mean, I've seen claims based on studies on animals that were giving really really high doses of stevia, like we're talking about just like dumping packets into your mouth all day long, that indicate that stevia might cause some hormonal fluctuations that could lead to infertility.  So you could basically save money on condoms I guess if you were doing enough stevia.  But in humans, like the review studies I've seen that are pretty comprehensive, it doesn't appear to have any adverse effect on health.  And I think the issue is stevia is what's mixed with.  Like a lot of times, you buy stevia in liquid form and it has a bunch of alcohol added to it.  Or you buy in powder form and it's got fillers, and it has maltodextrin added to it.  And so I think part of it is what that stevia is actually combined with.  You know what I'm saying?

Dr. Ruscio:  Yeah.  I mean certainly I think the best data we have is for the more classical artificial sweeteners like sucralose, aspartame.  If you would send me some of those studies, Ben, I'd be very happy to look at them regarding stevia.

Ben:  Okay, yeah.  ‘Cause like Truvia for example, people think that's stevia, but it's erythritol, it's Reb A, which is kind of like the healthy form of stevia.  And I know all of this 'cause I interviewed the guy that makes the soda I'm drinking, the Zevia guy.  And we took a deep dive into stevia.  And then it has all natural flavors in it, which we all know can be anything from MSG, to glutamate, to beaver anal gland, or whatever it's called.  So, yeah.  I mean like it depends on the stevia too.  Definitely something like Truvia, I'm not a big fan of.  It depends on the type of stevia basically, not to kick that horse to death.

Dr. Ruscio:  Sure. Yeah.  And I'd be happy to have a look at that.  There may have been some new, I'm just doing a quick PubMed search right now as we're talking, looking at stevia.  There may have been some new information published since we did a review on this for the book, which was probably about a year and a half ago.  So I would definitely be happy to look at them.

Ben:  Well over at bengreenfieldfitness.com/gut2, I'll put a link to my podcast episode on stevia and Zevia, who does not sponsor this podcast nor do I have any financial affiliation with them.  I just drink it like it's going out of style.

Dr. Ruscio:  And are the references from stevia all in there?

Ben:  They might be.  I'll check.  And I'll link to in the show notes too so that you can go read up on it to your heart's content.

Dr. Ruscio:  And Ben, not to cut you off, but before we leave the subject, there is one study I think is worth mention for artificial sweeteners, and this was not looking…

Ben:  Is that the one where people's genitals fall off and fly around the room?

Dr. Ruscio:  No.  Sounds like a very interesting read though.  This one was a San Antonio Longitudinal Study on Aging.  And this study was interesting because they isolated for the effect of “Do people who are diabetic or overweight and looking to improve their health gravitate toward artificial sweeteners?  And does that kind of skew some of the data that we have showing that people that consume more artificial sweeteners actually are heavier or have higher blood sugar?”  So it was a prospective design where they broke people into two groups, those who would just drink regular soda or those who would drink artificially sweetened soda.  So this is most going to be your conventional artificial sweeteners.  I don't think they advise anyone on using like a stevia sweetened soda.  So your typical store bought artificial sweetener sodas.  And what they showed was there was a dose dependent relationship.  Meaning the more artificial sweetened sodas the subjects drank, the greater their waist-hip, or their waist circumference became.  So they showed a dose dependent waist circumference gain for the more artificially sweetened sodas that these people drank.  And when they compared that to the other group that were drinking regular sugar-sweetened soda, they did not show any appreciable change in waist circumference.  So there was definitely a documented waist circumference change in this study that showed negative metabolic consequences.

And there was one other study that also looked at this, and they gave a bunch of people essentially artificially sweetened sodas, and they noticed that some people gained weight or had a worsening of their blood glucose and others did not.  So they labeled these people as “responders”, meaning people that had a negative metabolic response compared to non-responders.  They then took the microbiotas of both of these groups and transplanted them into mice, and it was only in the people that gained weight after drinking artificial sweeteners, it was only their microbiotas that caused a weight gain in the mice and not in the other people.  So there may be a faction of people that have a microbiotal predisposition toward weight gain from artificial sweetener use.

Ben:  It would be interesting to just like start drinking a bunch of diet soda and do a pre and post-poop test just to see what happens to the microbiome.  And by the way, I did one of these comprehensive microbiome tests the other day.  Total rabbit hole, but it was with this company called Viome.  I'm waiting on the results back from them, but apparently they have like this very comprehensive microbiome analysis from my tiny, tiny, tiny little spoonful of fecal matter.  Have you heard of this company?

Dr. Ruscio:  I have.  I don't know much about them but I heard of them just recently.

Ben:  Yeah.  Well, stay tuned.  I'm going to try and get over to the, the guy that owns it is like a billionaire who harvests rocks from the moon and parties with Richard Virgin, or Richard Branson.  Who's the guy who has Virgin Airlines?

Dr. Ruscio:  Yeah.  Richard “Virgin” Branson.

Ben:  Richard Branson.  Yeah.  So I'm going to go over there to Seattle probably this summer and interview him, and find out more about their technology and what they do, and have that be an excuse to go talk to a billionaire about poop.

Dr. Ruscio:  Yeah. (laughs)

Ben:  Anyways though, I think we have time for one other question.  I to talk about testosterone and the impact of a low carbohydrate diet on testosterone levels.  ‘Cause that was another thing that kind of happened to me when I was racing Ironman, eating a low carbohydrate, or really in this case a ketogenic diet, was my testosterone seemed to take a hit.  What's your take on this idea that you need to eat a lot of eclairs at night to keep the testosterone elevated?

Dr. Ruscio:  Well, that's another good question and I do see that there is some plausibility to that.  I think it comes out of kind of the same rules that one we follow for the thyroid, which if you're going to go on a lower carb diet, you should be looking at generally how you feel.  And in my experience, people tend to have all these symptoms shift together in a positive direction or a negative direction.  So if a male is having decreased drive, he's also most likely a little bit irritable, not sleeping well, doesn't seem to be remembering things quite as well, kind of all these signs of an excessive fasting type of response, meaning you're too low carb and you've been too low carb for too long.  But when people have improved testosterone, improved sex drive, let's say the main symptom of that, they may also be sleeping better and have better energy during the day.  So the thing to look for I think on the user end of this is are you moving in a good direction or a bad direction?  If you're moving in a globally bad direction and you're doing a really low carb diet, you may want to experiment with upping your carbs.

Physiologically, we know that carbohydrates are anabolic.  Insulin is anabolic, and that's fueled by carbohydrate consumption.  And we also know that we have a decrease in sex hormone binding globulin when we eat carbohydrates, and that allows there to be more free testosterone.  So definitely, we can, I think paint a reasonable case if you're too low carb for too long, you may be less anabolic, and that would include your free fraction testosterone.  And then if you're too low carb for too long also, your body starts going into a stress state.  And what happens in a stress state?  You start sacrificing the production of steroid hormones for the expense of stress hormones.  So I definitely think that there's some possibility for that.  We have some mechanism studies showing how that plays out in terms of how it affects certain hormone fractions.  So yeah, I think that totally could be plausible.  But does that mean [1:06:46] ______ be low carb?  No, it just means you have to kind of do some tinkering and see where you feel best in the low carb, or where you feel best in the carb spectrum.  And if you've been low carb for a while and you're feeling some of these negative feelings or symptoms, then try upping your carbs by 50 to 100 grams a day for a few days, see if you feel better, and then kind of continue to tinker from there.

Ben:  Yeah.  And I know that in some cases, long term low carb dieting have been shown to result in lower basal levels of testosterone.  But if you look at actual cortisol levels, in many cases you're looking at athletes with elevated levels of cortisol, which of course can increase your sex hormone binding globulin and throw off your testosterone to cortisol ratio even more.  And so in some cases, it might be this combination of low carb dieting with excessive activity levels that causes the impact on testosterone and not necessarily low carbohydrate intake per se. I would hazard a guess that many people, especially people who come from populations far north of the equator like you were talking about earlier who are eating a lot of wild caught fish, or grass-fed beef, or healthy amounts of fats, if they weren't doing, say, like Ironman Florida, Ironman Hawaii, and Ironman California and Arizona all in one year might actually not see an impact on their testosterone levels.

Dr. Ruscio:  Yeah.  I mean it's an excellent point and I think it's maybe good to look at that big picture perspective, which is not just your carb to testosterone intake ratio, but also look at how much stress you're under.  ‘Cause ultimately [1:08:17] ______ how much stress is your body under and can your body adapt to that stress.  And so one stressor's exercise, and another stressor is your diet.  And a little bit of stress metabolically by [1:08:33] ______ can be helpful.  But if you do that too much and/or you leverage that with too much stress in terms of training, or not enough sleep, or too much work stress, then you're going to put yourself into a syndrome where your allostatic load, your stress load is just too high, and now you start reacting negatively.

Ben:  Yeah.  Man, a lot here.  I kind of want to have some sweet potato fries now 'cause they were some leftovers from last night.

Dr. Ruscio:  Love those.

Ben:  Yeah, baby.  Well Michael, you sent over reams of data.  I really like when I interview 'cause you send me over so many studies.  So for those you listening in, everything we talked about, I’ll link to studies of in the show notes over at bengreenfieldfitness.com/gut2, that' G-U-T, the number 2.  I'll also link to Michael's website, his excellent podcast, Dr. Ruscio Radio, I'll link to my podcast episode with the good folks from Zevia soda, my podcast episode with Robb Wolf on his book Wired To Eat and the impact of different foods on blood glucose, and oh so much more, all the things we talked about as well as that recent study about how low carbing reduces fast food cravings and sugar craving.  So all sorts of interesting stuff in the show notes.  But in the meantime, thanks for listening.  And Michael, thanks for coming on the show, man.  I look forward to kicking your butt in arm wrestling tomorrow.

Dr. Ruscio:  Take it easy on me, okay?

Ben:  Alright.  I'll try.  Like sometimes I go into berzerker mode.

Dr. Ruscio:  We'll see.  We'll see who wins this time.  But someone's going to have buy someone a drink.  I know that for sure.

Ben:  Sounds like a plan.

Dr. Ruscio:  Alright, buddy.

Ben:  I'll drink from the free wine bar.  Later, man.

Dr. Ruscio:  See you, bud.



I first interviewed Dr. Michael Ruscio in the podcast episode “Why Healthy People Get Broken Guts, And What You Can Do About It.” 

In that discussion, we delve into:

-Dr. Ruscio’s personal diet, and what his typical day looks like (including his meal of choice at Whole Foods)…

-The surprising things that happen to your gut when you combine calories and high levels of physical activity…

-Whether athletes should fast, and what happens when an exercise enthusiast “stops the flow of calories” and fasts…

-How an “elemental diet” works to reduce stress on the gut…

-When you actually should consider starving the bacteria in your gut…

-Whether you can combat “overstressing” the gut with food by simply using things like digestive enzymes…

-The biggest mistake most people make with cleanses, enemas and detoxing…

-How you can heal damage to the valves passing through your gut…

-If you could test anything and everything going in your gut, what you should test…

-And much more!

Dr. Michael Ruscio is a functional medicine practitioner, researcher, and author. His specialties include autoimmune, thyroid, and digestive disorders. He consults clients locally in the Bay Area and remotely across the country. His clinical research is focused on digestive disorders. Dr. Ruscio has been a featured speaker at numerous conferences including the SIBO Symposium, PaleoFX, Ancestral Health Symposium, and an international symposium in London. He’s also spoken for several online health summits, including Sean Croxton’s Digestion Sessions.

Dr. Ruscio has collaborated with many authorities in the health and wellness industry, including Robb Wolf and Melissa Hartwig. He has been interviewed on several popular podcasts such as Sean Croxton, Robb Wolf, Ben Greenfield, and Jimmie Moore, and he’s provided clinical training for Designs for Health and the SIBO Symposium. Dr. Ruscio also conducts a very highly rated functional medicine podcast. You can visit his website and podcast here.

Today, Dr. Ruscio is back with the latest research on carbohydrates and the gut, and during Part 2 of our discussion, we dive into:

-Michael's take on the statement that “all carbs get converted to glucose so there is no such thing as bad carbs” and whether there is a consensus regarding the role of all carbs, good carbs, bad carbs, high carbs and low carbs…[8:11]

-Why Michael doesn't like food allergy tests or use them much in his practice…[13:10]

-The role of carbohydrates or carbohydrate avoidance when it comes to a digestive condition like IBS (gas, bloating, abdominal pain, constipation, lose stools)…[19:40, 21:45 & 32:10]

-How the microbiota influences this and whether people with digestive conditions need to feed their healthy bacteria in order to feel better, and if so, how do they do that if they're eating low carb…[20:20 & 23:45]

Whether a low carb diet really damages your thyroid…[40:40]

-The impact of artificial sweeteners on a low-carb diet and the truth about stevia…[56:15]

-Whether you really  need to run like the plague when a supplement or bar has, say, 10g or 20g of carbohydrates…[52:30]

-The impact of a low-carbohydrate diet on testosterone levels…[64:30]

-And much more!

Resources from this episode:

My podcast episode with Robb Wolf

My podcast episode on stevia and Zevia

-Article: Low carb diets decrease thyroid autoimmunity

A clinical trial comparing a low carb diet to a more traditional low fat diet found low carb worked better for treating type II diabetes.

Another clinical trial comparing low fat versus low carb for type II diabetes found they both work, but low carb worked better 

A paleo diet has also been shown to work better than a conventional lower fat/higher grain diet for type 2 diabetes

-There are many studies showing traditional low fat/high carb diets that increase fiber, fruit, vegetable and whole grain intake all help with heart disease and obesity, including:







A recent trial found that a paleo diet improves cholesterol levels to a greater extent than traditional heart-healthy (low fat) dietary recommendations.

Another study found consuming a paleo-type diet for only two weeks was able to improve several cardiovascular risk factors compared to a healthy reference diet (traditional low fat diet) in subjects with metabolic syndrome.

A paleo diet caused better improvements to blood sugar control and several cardiovascular risk factors compared to a diabetes diet (traditional lower fat/higher carb) in patients with type 2 diabetes. 

A systematic review with meta-analysis shows the paleo diet is more effective for metabolic syndrome than standard nutritional recommendation diets which are typically lower fat and higher carb/fiber.

What about the best diet for weight loss? A systematic review with meta-analysis of 53 studies found that low carb diets are better for weight loss than low fat diets.

Low carb diets may improve thyroid autoimmunity issues

-Hunter gatherer lifestyle (paleo diet) improves metabolism, but t3 decreased

-Article: Low Carb(-ing) Reduces Fat & Fast Food (10-20%) Cravings Plus 60% Less Hunger After Meals in Obese Men/Women

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