[00:00] About Stacy Sims
[01:47] The Percentages of Endurance Athletes with GI Distress During a Race
[03:35] How the GI Distress Occurs
[08:26] Neural Activity in the Gut During Training Versus in a Race
[16:54] What Stacy Would Eat for an Ironman
[27:35] Exercise and Gut Muscles
[29:44] GI Issues with Men Versus with Women
[30:56] How Women Can Deal with The High Hormones
[32:10] Race Day Meals
[38:56] Using Electrolytes
[44:05] Emergency Solutions on Race Day
[47:09] End of Podcast
Ben: Hey, folks. It's Ben Greenfield here. And if there's one subject that seems to baffle folks more than just about anything else, it's how to fuel your body during an endurance event like a marathon, or triathlon, or anything else where stomach issues can tend to creep up on you, as well as knowing just how much you're supposed to eat, how much you're supposed to drink, those type of things. So, I have a real expert on the call today. She has a PhD in environmental exercise physiologist, she is a nutrition scientist expert, she works with the Trek Professional Cycling Team and has worked with many other cycling teams in the past, as well as a lot of triathletes and endurance athletes. She, herself, has done a Half Ironman, Ironman triathlons, and she's one of those people that knows both the science as well as what goes on in the trenches. So, her name is Dr. Stacy Sims. And Stacy, thank you for coming on the call today.
Stacy: Thanks, Ben! Thanks for having me.
Ben: So, I guess we should probably just jump right into this. But in terms of GI problems among runners, among endurance athletes, I hear about it a lot from the folks that I coach, you read about it a lot in people's race reports, but do you have any figures in terms of how many people this happens to, in terms of kind of the rough percentages of athletes who experience some kind of GI distress while they're out there racing?
Stacy: Yeah. So, when you're thinking about shorter races, shorter duration, about 70% runners and triathletes experience GI distress. And the longer the race distance and the time you're on your feet, the greater people experience GI distress. So, it can be up to 85% of endurance athletes to actually experience some kind of GI distress.
Ben: So, man, it seems like you're pretty much guaranteed that at some point, something's going to go on with your stomach?
Stacy: Yeah. So, a lot of people report it as simple bloating and the sloshing feeling, and then other people are severe is having to stop on the side of road with diarrhea, or IBS, or something like that. So, there is a variance in the “what is GI distress”. But it's a pretty high percentage of endurance athletes that actually do experience some sort of stomach, GI problem.
Ben: So, you can pretty much assume when you're out there and your stomach is talking to you that it's more than likely that, if you're in a group of 10 other athletes, that a good seven or eight of them are kind of experiencing a lot of the same things, huh?
Stacy: Yeah. And it turns to conversation.
Ben: Yup. So, let's delve into the science of this. When you get gut issues while you're out there exercising, what exactly is going on physiologically that makes it something that maybe you did just fine in training and you didn't experience GI distress when you were doing swimming, or cycling, or running, or anything like that leading up to your events, all of a sudden, what goes on when you get into a race as far as physiologically in the gut that causes these issues to all of a sudden become a problem?
Stacy: So, I want to take just one step back and try to get people to understand the difference between illness dehydration and what happens in the gut versus exercise-induced dehydration that happens in the gut. ‘Cause a lot of people will turn to Pedialyte or some other kind of GI rehydrater as a pre-hydrater for a race or a rehydrater after a race, and it's not ideal. Because when you're sick and you have diarrhea and all those other kinds of issues from a virus, or jetlag, or something like that, you don't have the shunting of the blood from the gut. So, you still have full blood flow to all the intestinal cells and there's no deviation to the working muscles. So, it's okay to take things like Pedialyte 'cause it will help. But when you start exercising, it's a different scope on the dehydration and what's happening in your intestines because the blood is diverted to the working muscles as well as to the skin to help offload heat. So, blood flow to the gut is pretty compromised. And so, this is where it becomes a nuance of GI distress during exercise. You have the impact of running that is really harsh and can cause some eccentric load on the intestinal muscle itself. And then what you're eating and drinking also impact it. One of the biggest things is when people are taking things with sodium chloride. So, chloride is really critical…
Ben: Which is in almost everything, it seems like.
Stacy: Yeah. But in the intestinal cells, it's part of the whole cell membrane potential that allows fluid, and glucose, and everything to cross from the intestines into the system. And when you're taking in a lot of sodium chloride, sodium will be taken up with water, not necessarily through the intestines, but it starts in your esophagus on its way down. But when the chloride ion disassociates from the sodium, you change the membrane potential at the level of the intestinal cells and it causes them to kind of open up and release endotoxins. So, when you have this endotoxin release in heat shock proteins that cause issues as well, then you are triggering the GI distress.
Ben: Now, is there a reason for that? Why would we have a mechanism that would cause when the intestinal cells open up, to have an endotoxin release or a heat shock protein release? Is that a protective mechanism to keep us from going too hard? Do you know why that would be?
Stacy: Yeah, for the most part because the human body's temperature is very, very finite in how much it can move. You sit about 37 degrees C at rest, and then there's some argument of what is your dead-end point, not dead in the water kind of thing, but fatigue end-point being 40 to 41 degrees C. So, that's a very narrow window. And your muscles, your working muscles and your intestinal muscle cells will get warmer and hotter than, say, other parts of your core. So, it becomes a denaturing of proteins, it becomes a feedback mechanism, and your body's like, “Wait a second. We need to do something to protect this because we're getting to the end-point of temperature where things start to really fall apart.” So, this is where you have this release of endotoxins as a feedback, you have kind of gut shutdown as a feedback that things are getting a little bit too hot for continuation.
Ben: And can that type of thing happen even if you’re in, maybe, conditions aren't so hot? I mean, can the gut heat up to that point?
Stacy: And then the other aspect that you have to remember when you're racing, you have a lot more epinephrine and adrenaline that's being released, and this is kind of a catabolic hormone as well for fueling. ‘Cause when you're training, you're a little bit more relaxed and you are in a more controlled environment. But when you get into a race situation, it's like everyone starts a little bit on edge and you can feel the caffeine and adrenaline buzz at the start of a race. And all of these things contribute to a different environment from a training environment.
Ben: Now does that kind of effect, I know that the nervous system and the gut are highly related, but as far as kind of like how those two aspects are related, is there any change in neural activity in the gut or anything like that that would cause it to be different in a race situation than a training situation, or does the heat effect that neural activity or anything of that nature?
Stacy: Yeah, somewhat. And it also depends on what kind of supplements that group people are using on race day versus what they do in training. ‘Cause a lot of people will start shooting that caffeine and stuff a little bit too soon, and this alters some of the neural control just the way that caffeine receptors are in the brain as well as all systematically through the body. And then you have more of the parasympathetic response, that's kind of the part of the flight or fight response and that affects the neural activity that goes down into the intestines as well. So, there's quite a few different scenarios that can trigger things to happen on a race day that doesn't ordinarily happen in training. So, it's beginning to realize what you can do to take to kind of stop or attenuate those things happening on race day, and along this is what kind of supplements you're taking, or what you're actually ingesting, timing of food, and all that kind of stuff.
Ben: Gotcha. What about actual absorption, like the way that food's absorbed from your stomach into your intestines, through your intestinal cells, into your bloodstream? Does that change during the race or does it change as your body heats up when you reach higher intensities?
Stacy: Yeah. Because as you become dehydrated, like I said, you have reduced blood flow to the gut. And so, that slows your gastric emptying rate. And then the other thing is what you're eating and the concentration as well. Anyone who has heard me give a talk will know that I absolutely abhor gels because gels, GUs, those kinds of things are concentrated carbohydrate. It gets shoved into dehydrated gut, and no one that I am aware of is actually consuming the eight to 10 ounces of water that they say to have with every sachet. So, you're taking this concentrated carbohydrate, putting it into a dehydrated gut, it changes the osmotic pressure and body water has to come from within the system to dilute it in order for it to be absorbed. Meanwhile, it's sitting in the gut, sloshing, and anything else that you ingest with it kind of gets held in the gut too because nothing's passing through.
Ben: Interesting. So, when you've got the gels sitting there in your gut metabolizing, what goes on from a standpoint of kind of the way those oxidizes there in your stomach or the heat that's produced along with them?
Stacy: So, the gels are usually fructose and/or maltodextrin oriented. And by the nature of them being a longer molecule and having to go to the liver as a final step for oxidation, they actually release a lot more heat that is glucose, sucrose based. So, you end up with a greater heat storage. And then when you're thinking about what's happening actually in the stomach, with slow gastric emptying, it's kind of like if you were to take a whole bunch of icing in and put it in a sink and then try to run water down and the water just can't get through because it has to dissolve the icing first, and that's…
Ben: Right. You mean like sugar icing from a cake?
Stacy: Yeah. Like the Betty Crocker stuff you get in the tub and you want to throw it out and you try to wash it down the sink, and it doesn't really quite get through until it's dissolved enough. And that's kind of what's happening with the gel, except instead of running water, your body's having to throw that water in from somewhere else. So, it's kind of an effective dehydrator.
Ben: So, what you're saying is gels basically produce more heat in your gut than perhaps some other sources of sugar, specifically gels that are made up of a long chain fuel, like a maltodextrin?
Stacy: No. Maltodextrins kind of have the same issue, and it's the type of sugar, but also the osmolality. So, it's better to do something like Bloks or Jelly Beans. It's a small amount of carbohydrate that gets introduced. ‘Cause a sleeve of Clif Bloks is maybe 200 calories, whereas one gel is 100 to 110. So, people slug down one or two gels in a very short period of time in comparison to eating a whole sleeve of Bloks. So, it's kind of a titration effect. If you're having a small amount of carbohydrate at a time, you don't get that gut reaction 'cause your body's like, “Okay. Well, I can actually deal with this little bit of carbohydrate.” Get it into the system so your blood sugar stays a little bit more constant, and you don't have this big glug of stuff that's hanging out in your GI tract.
Ben: So, the type of sugars that make up things like Bloks, or Chomps, or Jelly Beans, or these type of chewable sugar sources, while it may be the same type of sugar that's in a gel, what you're saying is that we tend to consume things like that in smaller amounts and kind of ration them throughout an hour versus kind of eating them all at once via a gel source?
Stacy: So, yes and no. So, gels are primarily fructose and maltodextrin, which have the heat issue. And if you're thinking about Jelly Beans, or Bloks, or Sharkie's and those kind of gummy things, they're primarily sucrose-based. So, sucrose is readily absorbed. It gets broken down into glucose and fructose. What's going on, the glucose gets absorbed, the fructose works with the glucose to get out of the system a lot faster. So, there are co-factors involved. When, you start just ingesting fructose or just ingesting maltodextrin with fructose, this is where you have the issue with the heat, and then you have to look at the concentration of it. So, if you're eating small amounts, then the osmolality and aspects of what you're ingesting is lower than slugging back something that's concentrated.
Ben: So, what you're saying is we're kind of turning over the label and looking at something that we're planning on eating during an intense event or a hot event, we should be looking for, basically, something that contains fructose plus a combination of, or a combination of fructose plus a simple sugar like a glucose or a sucrose, or like just glucose or sucrose but not like a fructose and a maltodextrin or a fructose by itself?
Stacy: I'm going to say no to fructose across the board.
Stacy: Glucose, sucrose are the two best sugar combinations. One, they encourage fluid absorption. And two, they're not as harsh on the body to actually digest, get through the system, and get out to the working muscles. Fructose has an extra step where it actually has to go to the liver to be oxidized. And I know that there's a lot of research out there that's saying a combination of glucose and fructose, or fructose with another type of sugar is great for carbohydrate absorption…
Ben: Yeah. That's what I was going to ask you, actually.
Stacy: Yeah. So, this is where I kind of deviate, where you're looking at what's most important in a hot race, staying hydrated and keeping the gut working or ingesting a lot of carbohydrates. And this is where people start to go kind of awry, where they're like, “Okay. Well, I want a lot of carbohydrate. So, I'm going to look for those that maximize carbohydrate availability and carbohydrate absorption. So, this is where they turn to things like Gatorade, and the Cytos, and all those other, the Hammer products that all are “liquid calories”. But, it's kind of the sofa bed analogy where it's not a good bed and it's not a good sofa. So, those kinds of things, it's not a good fuel and it's not a good hydration solution. So, if you're looking to maximize fluid absorption with some carbohydrate, you're looking for a glucose-sucrose combination. And then you have a real food or solid food in your pocket to top up the carbohydrate macronutrients that you need.
Ben: So, talk to me a second about practical aspects here. Glucose, sucrose, and then you mentioned solid food to top things off. What would a typical scenario look like? Like let's say if you, yourself were to go do Ironman, what would you be eating?
Stacy: So, I would start solid and work my ways in my salad. So, what I mean by that is I would have had a good lead in to the race through my taper week. So, I wouldn't change my nutrition during taper week, so that as my volume intensity drops down, I'm effectively glyco loading and carbo loading throughout the week 'cause my nutrition hasn't changed. And then the morning of, making sure that I have good protein and carbohydrate combination, oatmeal with a little bit of whey protein, or some people are doing Ensure or something like that. It depends on what your stomach can handle. Then when I get out of the swim in T-1, I'm going to have a bar that I'm going to shove in my pocket, I'm going to eat within the first 10 miles of the race.
Ben: For that bar, you're wanting to eat a type of bar that doesn't have fructose and maltodextrin in it?
Stacy: Right. So, preferably an uncoated one that doesn't have fruit and nuts in it. A go-to for a lot of people I work with are the toasted, uncoated LUNA bars or Mojo bars that Clif Bar puts out.
Ben: Gotcha. Okay.
Stacy: So, then you're getting something solid in your stomach before you start getting into any kind of low body water. And then I aim for 45 to 50 grams of carbohydrate, plus about 10 grams of protein per hour, which is a little bit, well, I shouldn't say a little bit, it's usually a lot lower than what comes out in a lot of other people's research saying you can go up to 90 grams of carbohydrate per hour. It's a bit too much when you get up there, because most of that research has been done on elite college-aged, 18 to 20-year old white men that are in a lab situation, and they don't take into account gender differences or sex differences, I should say, menstrual cycle status, intensity of the race, environmental conditions, or any of that. So, you can always come back from a low sugar, but you can't come back from dehydration. So, this is where I always tell people to go on the lower side of carbohydrate intake. And then if they start to get hungry, you can top up that. But for the fluid intake, making sure that it has low osmolality, glucose-sucrose with some good sodium, magnesium, and calcium. Yeah, I'm drinking that kind of drink throughout the race, and then starting solid, working my way semi-solid. Trying to stay solid as much on the bike as possible. I mean, it could be anywhere from the engineered nutrition in Mojo Bars, to a peanut butter sandwich, or a turkey and cheese sandwich that's shoved in my pocket, or salted potatoes, or some other kind of real food that I've put in my pocket or in my special needs bag.
Ben: So, basically, something solid that again, isn't a bunch of fructose and maltodextrin?
Ben: And that's just kind of like to top things off at the end of each hour?
Ben: Okay. Gotcha.
Stacy: And you're eating bits along the way. A lot of people set their watch and go, “Ooh, 15 minutes. Got to eat something.” And they tend to kind of overeat whenever their alarm goes off. So, if you're kind of eating small bites along the way and you make sure that you finish your designated carbohydrate intake per hour, you end up with a little bit more steady stream. And it takes a little bit of practice, and this is what you do in training.
Ben: Gotcha. I've always come from the standpoint of looking at total carbohydrate absorption. Meaning, usually looking at fructose and maltodextrin-based liquid or gel sources, looking at this from a heat production standpoint and kind of an energy of digestion standpoint, that being kind of a new process. In terms of brands, and this isn't a commercial for any brand. Just so listeners know, I have no clue what Stacy uses. But glucose, sucrose, are there specific brands of drinks or specific choices that you make in terms of the actual things that people, let's say somebody's listening in now, they've got an Ironman in eight weeks, they want to go buy some stuff and experiment with it, what would they use?
Stacy: So, there's a lot of things on the market. The big ones out there that are on the race courses for the most part are things you want to avoid. The Ironman Perform drink that's out there is okay, but you want to have it diluted. The Gu Brew is okay. But again, you kind of want to have it diluted.
Ben: By how much?
Stacy: So, it's one-third dilution factor. So, you're making it one-third as strong as what they say. And then I think we'll get to a point of what about electrolytes and stuff in a second. If you're eating real food, then you're topping up the carbohydrate and the sodium and potassium intake, so you can afford to have the diluted sports drink because the idea is to maximize hydration. So, Kai Nutrition is another one that's coming on board.
Stacy: Yeah. K-A-I Nutrition. So, they have an active recovery drink, or active drink and a recovery drink. They're both low in osmolality.
Ben: Those are like the sucrose and glucose that you talked about?
Stacy: Yup! All of these are. The Powerbar Perform one, I think, has a little bit of maltodextrin and dextrose, which is better than a fructose.
Ben: You mean the Powerbar Perform drink or the Powerbar gels?
Stacy: The drink. Okay.
Ben: Alright. Well, cool. I think folks have some ammo, at least some knowledge so they can start turning over the label on stuff and looking at it. I want to backpedal. Because before I started bugging you about what you actually eat when you're out there, we had gone through what's actually going on physiologically during intense exercise or dehydration that causes gut issues. You described about the endotoxins getting released by the cells and decreased absorption through the intestinal cells. And you mentioned caffeine as being one thing that can aggravate this issue, you mentioned starting to take that too early. I mean, obviously, caffeine is an ergogenic aid and can help, but do you have kind of a best practices that you recommend for caffeine in a situation like this?
Stacy: So, yeah. If you're a habitual caffeine user, you just keep using caffeine. You wake up, you have your espressos or whatever. If you're not a habitual caffeine user, then you want to wait 'til the second half of the bike ride. And you're not taking caffeine pills, because the anhydrous caffeine that's in there, that is in stuff is notorious for giving you shakes in the runs. So, you want to look for something like green tea extract or, and I get bombarded when I say, this 5-Hour Energy. ‘Cause if you look at the label of 5-Hour Energy, it's just a big shot of B vitamins with some caffeine. So, those are kind of two things that I would say, if you're a habitual caffeine user and you need that extra boost of caffeine, then you’re going with something like 5-Hour. If you're not a habitual caffeine user, but you need that extra boost of caffeine, then you're going with something like green tea extract. And you can get this in pill forms or you can get some food in stuff that's fortified or supplemented with green tea extract, and it's the caffeine aspect that you want. If you're out on a training ride and you know that you have a big brick, then people often stop for a low fat or a nonfat mocha. So, you get a little bit sugar, and some protein, and some caffeine ready to go. So, it's kind of fueling by fire.
Ben: Okay. Gotcha. People who are out there taking a lot of other supplements or possibly medications, which ones would you highlight as having potential, aside from just like straight up caffeine pills, which you mentioned, potential to aggravate the gut issue even more?
Stacy: Sodium bicarbonate. So, people will take or follow the sodium bicarb loading for lactic acid buffering or for preloading…
Ben: So, we're talking about stuff like SportLegs, or Hammer Fatigue Caps, or those type of things?
Stacy: Yup! So, when you're looking at those kinds of things, you want to see what the concentration is. If you're going to go with something like that, then you want it to be a bicarbonate and a citrate combination. You don't want any kind of chloride, 'cause I know that there are different variations like SportLegs, and salt tabs, and those kinds of things that use potassium chloride with sodium chloride.
Ben: For the reason that those cause the intestinal cells to open up and the endotoxin issue?
Stacy: Right. And sometimes [0:26:10] ______ are high in sodium bicarb, but they also are linked with potassium citrate. So, the citrate and the bicarb kind of work together to reduce the GI distress issues that you would have with bicarb. And the other thing that is notorious for causing kidney and GI distress are non-steroidals. So, people who are taking Advil, or Aleve, or something like that…
Stacy: Yup! And it interferes with some of the receptor sites and function of the kidney, which changes fluid balance and can also contribute to GI distress.
Ben: Gotcha. Okay. So, those would be some of the major ones to essentially avoid if you don't want to experience this type of GI distress?
Ben: So, you're looking for caffeine pills or regular kind of caffeine sources aside from like green tea or 5-Hour Energy, you're looking at things like ibuprofen. And then also if you're checking the label, anything that kind of says chloride?
Ben: Okay. So, does exercise actually cause changes in your gut muscles or the way that your intestines actually kind of operate as far as like the way they bounce around, the way they move? What exactly is going on from that standpoint?
Stacy: So, it's not the exercise per se. It's the heat and the, well, I guess it could be mode of exercise. Because a lot of people are just kind of experiencing bloating on the bike, but then when they get up off run, I've yet to meet an Ironman athlete that doesn't have some kind of stomach pain disorder, GI problem for the first five miles, and it's because you get off from the bike that's non-impacting to starting to run. And then all of a sudden, you have this bouncing of the intestines and the impact, and that will cause some GI problems. And the hotter you are, the more susceptible you are to the GI. So, staying on top of your fluid and then doing things like Tums, or magnesium, or something like that before you get off the bike so you have some kind of coating in the stomach before you actually start running helps with the attenuation of any kind of GI problem.
Ben: Interesting. That's an interesting tip. Is stuff actually moving around? Are your intestines actually, when you start running, kind of changing position? Does that cause to move through more quickly? What is it about running from kind of a mechanical standpoint?
Stacy: It's the actual bouncing of everything that's in your thoracic area. So, you have the intestines that start bouncing from the impact of running that hit other organs, and it's just kind of like a big paint shaker, that all the sudden you go from pretty stable to big paint shaker. And yeah, some people, it causes IBS or quicker gut transit. Other people, it just kind of sits there and kind of get a backlog in the stomach, so you have all the sloshing. So, it's a little bit independent, but again, it's like going from pretty stable to putting everything into a paint shaker and moving up and down.
Ben: Okay. Gotcha. So, how about men versus women? I personally hear about this more in women. Is that just sheer perception or are issues like GI issues more prevalent in women than men?
Stacy: So, it's very much more prevalent in women who are in the high hormone phase of the menstrual cycle. So, estrogen, progesterone, even if you're on the pill, you have similar responses. It's the estrogen and progesterone that changes the woman's body, makes her have a higher core temperature, so she has less room to that end-point, so she's running hotter. She also has a decrease in her plasma volume by about 8%. So, these are already contributing to triggers for GI distress. And then, the estrogen affects prostaglandins, and the prostaglandins can also affect intestinal cells and allow them to be a little bit more lax and open up. So, this is why a lot of women get diarrhea right before their period starts. So, yeah. A lot of the times when you hear women are having GI distress, you talk to them and you find out that they're in the high hormone phase of the menstrual cycle. So, it's not a misnomer. It actually is a true sex difference.
Ben: So, are there any kind of quick tips you have for women that they can use during a high hormonal phase of their menstrual cycle?
Stacy: Yeah. So, one of the best things to do about two weeks before their period starts is to start taking about 250 milligrams of magnesium and some omega 3 fatty acids. ‘Cause that helps with that prostaglandin interaction that you have with estrogen, but you can't really do much about the plasma volume and the heat change or the body temperature change, 'cause that's just a physiological thing. So, it's staying on top of hydration and actually making sure that what you're drinking is hydrating instead of being a carbohydrate source.
Ben: Okay. Got you. I want to kind of move on real quick to that race day meal that you mentioned and kind of what to eat, or more specifically what not to eat for your race day meal, when you're waking up in the morning and you're having something to eat, or I guess even in the days leading up to the race if that comes into play here. What are the most common mistakes that you see athletes making when it comes to race day meal planning? And kind of the second part of that question, are there specific things, specific compounds, specific ingredients that they should be just avoiding like the plague?
Stacy: A lot of it starts the night before. The big pasta loading, carbo loading dinner that a lot of people will have the night before a race, it kind of sets you up in a bad start. And the fact that you end up with a lot of extra insulin, and ghrelin, and leptin, and all these things that are involved in sugar metabolism. And you also end up with extra bloat because of the carbohydrate and water combination. For every gram of carbohydrate, you have four grams of water. And this water will be used eventually during a race, but you wake up feeling really lethargic and bloated, and your metabolism's a little bit off. And with the vagal response of nerves, so, it's race day, you've gotten short sleep or poor sleep, you have a lot of adrenaline going, you're running all these scenarios through your head, you're already having a little bit of blood compromise to the gut. So, getting up and having something that's really heavy and just sitting there is a lot of times not the right thing to do. So, if you're going to do something like oatmeal, make sure that it's kind of runny oatmeal, not a big bowl of heavy, thick meal.
And you want to have some kind of light protein. So, this is where pea and hemp flour protein powder comes into play. If you can handle dairy, then using whey isolate protein with some almond milk, so it's a little bit coating to the stomach, gives you a little bit of protein. You have the carbohydrate from the oatmeal. But then, some people can't handle that either, so then they turn to things like Ensure, or Complan, or some other kind of liquid breakfast. And I always try to steer people the other way to making their own with their own whey protein powder and almond milk. Because if you look at the ingredients in things like Ensure, they're chock full of fructose, fiber, they have a lot of chloride molecules in them as well as the fortification. So, you're kind of setting yourself up for a little bit of GI distress before you even get started. One of the better things to do is to kind of play around and see how your stomach does on short sleep and nerves. Some people will have go-to breakfasts, but the biggest concern is to top up carbohydrate and to get some protein on board. So, you're not trying to actually load for the race. You're just trying to top up.
Ben: What kind of thing would you eat before an Ironman triathlon?
Stacy: Probably what I have most mornings before training, and it's berries, some bircher muesli. So, it's the oatmeal with almond milk that's been put in the fridge the night before. So, it's not cooked. So, it's already pretty easy to digest. And then, I top it up with a little bit of whey protein powder. And then about an hour later, I'll have some toast with some almond butter and salt.
Ben: Gotcha. So, you're basically having like a soaked, easy-to-digest carbohydrate with some protein added. And then a little bit later, kind of topping that off with a little bit more carbohydrate and a little bit of fat?
Stacy: Yup! Yup!
Ben: Gotcha. Okay. Cool. Good suggestions. How 'bout artificial sweeteners? Things like sucralose and anything else that we might tend to find in a pre-race meal, or even in something that we might have out there with us on the course. You talked about avoiding fructose and maltodextrin as far as your carbohydrate fuel sources and some of the issues with gels, but what about artificial sweeteners?
Stacy: Yeah. So, sugar alcohols, like xylitol, are becoming more and more popular in some of the products. It ends being 40% less calories than sugar with the same sweetness, so this is kind of in your low carb supplements. Also found in chewing gum. And sucralose is the other notorious one that's in like CamelBak Elixir, and Nuun tablets, and things, and they both cause bloating and GI distress. So, staying away from artificial sweeteners is really good idea. And the fact that even at rest they cause bloating by the nature of their compound and the fact that they're primarily derivatives of corn as a sugar alcohol. So, doing something like a Nuun or a CamelBak Elixir is fine if it's an hour or two. But when you start ingesting a lot over the course of time, then you get this build-up of sucralose that can cause a lot of the intestinal issues that we talked about earlier, separation into endotoxins and stomach bloating, and xylitol does the same thing. So, small amounts, okay. But continuous use in one day of a race, it's not a good idea.
Ben: So, while most of us aren't chomping sugar-free gum during the race or eating a lot of sugar-free foods, you should even be careful with things like these effervescent electrolyte tablets that have sucralose in them?
Stacy: Yup! And some of the Hammer products are also full of xylitol and maltodextrin, just 'cause they're trying to keep the osmolality low so they have better absorption, but they still include the xylitol, and then that gives you issues.
Ben: Alright. So, folks who are taking notes furiously right now, so far we've got the list of things to look for would be fructose, maltodextrin, chloride, xylitol.
Ben: Yeah, sucralose. Caffeine, depending on the source of the caffeine. Okay. Cool. Now, let's go ahead and, we mentioned about sports drinks and how you'd say that things like the PowerBar Performance or the Gu Brew would be okay if we kind of cuts these down by about one-third. Now, those are obviously, for a lot of people, the electrolyte source. That's what they were designed for is the optimum hydration along with calories. Now do you think that we need to be using electrolytes? I've had Tim Noakes on the show before, and he says the body does a pretty good job maintaining plasma sodium levels if you're not taking in electrolytes. And if you think we should use electrolytes, do you recommend certain forms over others? Because there are a ton of different forms of salt tabs out there on the market.
Stacy: Right. I know Tim. He's a good guy and I often get asked this question, 'cause you have Gatorade, that's on one end of the spectrum, you have Tim Noakes that's on the other end of spectrum, and it's actually somewhere in the middle. So, if you're well-fueled and your eating real food or food with salt in it, then you're going to be okay for sodium. You don't need to take salt tablets. This is another kind of misnomer that Ironman triathletes have where, “Oh, I'm going to cramp. I need to take salt tablets.” But it's not. Cramping is such a nuance. It could be neuromuscular from the jackknife position you have on your bike. It could be the potassium, most people are low in magnesium. So, it's not what you do on race day, but paying attention to how you get into the race. So, the week or two weeks leading up, making sure that you're topping up with magnesium, making sure that you're eating, you're salting your foods, you have all this already in your system. Again, as you're saying, there are different compounds. There's carbonates, there's chlorides, there's citrates. If you're looking to coat the stomach a little bit on race day and you're starting to cramp, then going for a magnesium carbonate or a calcium carbonate, which is what Tums is, is great. If you're looking to kind of top up during the week, then going for citrate-based compound is good 'cause then you have an increase of your citrate storage, which helps with your Krebs cycle and your aerobic metabolism.
Ben: Why are you recommending, specifically you said carbonate, and I know a lot of people just look at something and they're just like, “Oh, sodium. Okay. I'll take it.” You talked about the issues with chloride, as far as citrate goes, using magnesium carbonate versus magnesium citrate, why are we avoiding citrate in something like a race-type of condition?
Stacy: It's not so much you're avoiding it. It's trying not to take supplements on race day specific for cramping.
Stacy: Like all the electrolyte tablets. People kind of put them in their pocket, it becomes a placebo, nocebo, “I need my salt pills”, “I need my magnesium pills”, and that kind of stuff. If you're doing something on race day and if it's specific for cramping and it's kind of the go-to, then citrate or carbonate is fine because the citrate works with your aerobic metabolism. But leading up to the race is when you should really be paying attention to your trace elements, making sure that you're hitting what you need to. So, it's already in the system, it's already being absorbed, there's extra storage, and kind of stuff of the citrate, of the magnesium, of the sodium, all those kinds of things. But if you're starting to have GI distress and you aren't using Tums, then you want to make sure that your electrolyte tablet is carbonate-based if you're having the GI distress and cramping. Does that make sense?
Ben: It does. What's an example of a brand out there that uses carbonate verses citrate as an electrolyte source?
Stacy: So, this is where you kind of have to go to like Pharmaca or you can even go on Amazon and get something like Magnesium Calm, 'cause they use a carbonate. And then there's a couple of others. So, it'll list the ingredients, and getting a magnesium, or a potassium, or a sodium, or not sodium, sorry, or a calcium carbonate is pretty easy if you look at the label.
Stacy: Most of the sports supplements that you buy in specialty shops are chloride because you have potassium chloride, you have magnesium chloride, you have sodium chloride. So, just paying attention to what's on the label.
Ben: Okay. That makes sense. In a nutshell though, with electrolytes, what you're saying is, say, I'm going to Ironman Hawaii and I'm going to be competing down there, smartest thing for me to do is to get my hands on like a good liquid mineral source or like a full trace mineral source and be sure to just keep myself really taken care of from an electrolyte standpoint so that I'm not going into the race depleted. And then if I am going to use electrolytes, use an electrolyte source that doesn't have chloride or citrate in it, but is preferably like a carbonate source.
Stacy: Right, right. Exactly.
Ben: Makes sense. You had mentioned Tums, and that's fine if you want to elaborate on that. I am kind of curious about that. But as far as like your final tips that we can use if we find ourselves out there and maybe we've followed all your rules or maybe we haven't, but we find that we've got GI issues, what are some final tips you can give folks who just need to pull out the emergency stoppage to get things to settle down?
Stacy: So, a lot of people who have this GI problem, it starts on the bike and they start getting the bloated feeling. So, this is not the time to stop drinking, but making sure that what you're drinking is that low carbohydrate, it's sucrose, glucose. So, you're still pulling in fluid, and then letting your body settle. Part of the issue is when you're eating and drinking and it's kind of mixing and you're having all these problems that we talked about with heat, and oxidation, and all that kind of stuff. So, lowering the food intake, staying on top of the fluid. That'll help get rid of some of the bloating. And then when you get to T-2 of any race, having some real food. So, not a bar, not some Bloks, anything like that. It could be as simple as white bread with some blueberry jam and salt. So, you're having quick hit of carbohydrates from the jam and the white bread and topping up a little bit of sodium to help fluid get out of the gut. And this is also the point where I tell people to take Peppermint Tums, 'cause peppermint is a natural anti-nausea soothing agent, just like ginger, and then you have the calcium carbonate from the Tums that actually helps coat the stomach.
Ben: Okay. Cool. And as far as folks who maybe are gluten intolerant or avoiding bread, I'm one of those people, let's say potato with a little bit of jam on it. Would that also be okay?
Stacy: Yup! Sweet potato and salt's my go-to.
Ben: Cool. I love that meal. Man, this is a ton of really fantastic information. I was actually just at a triathlon where I was watching Lance Armstrong compete and he was complaining about having GI issues and hydration issues during the race. So, hopefully he listens in and maybe he could pick up some tips 'cause you're full of great information and it was fantastic to be able to pick your brain today. I think this is really going to help folks out. So, Stacy, any final words?
Stacy: No. Not really. Other than really paying attention of what you're drinking hydrates you and what you're eating actually fuels you. ‘Cause a lot of people neglect the idea of nutrition and leave it to the sport nutrition companies, and a lot of that's been based on marketing. So, pulling it back a notch and paying attention to what you're eating is really going to go a long way in how you're racing and feeling.
Ben: Fantastic. Well, folks, I will be putting any notes that I was taking during Stacey's interview over on the show notes at bengreenfieldfitness.com. If you've got follow ups, leave them as a comment, or a question, or feedback right there in the show notes. If you, yourself, have some advice, if you know of some brands that kind of stay true to what Stacy has recommended, feel free to leave them there in the comments so we can all help each other out. And Stacy, thank you so much for coming on the call today.
Stacy: Yeah! Thanks for having me. It's been fun!
Last week, at Ironman 70.3 Galveston, Lance Armstrong decimated the field on the bike, but then slipped to a disappointing seventh place finish due to hydration and nutrition problems during the run.
So why does a guy like Lance Armstrong have gastrointestinal issues during a triathlon?
And what should you be eating during a triathlon?
In today's interview with Dr. Stacy Sims, you'll find out what to eat during a triathlon, and also learn fascinating new information about fueling that is going to change many of the recommendations that I personally make, and the way that I eat and drink during Ironman.
Dr. Stacy Sims is an Innovative Exercise Physiologist, and a Nutrition Scientist of Thermoregulation, Hydration, and Performance Nutrition, and also involved with “Kai Nutrition“. She is an accomplished athlete in her own right, having ridden as an elite women's cyclist, won multiple Xterra events, and even raced as a pro triathlete. Her cutting edge research with athletes has led her to work with the likes of Garmin, RadioShack and Lance Armstrong where she has helped athletes of all abilities find the extra edge through science.
During my discussion with Stacy, I ask her:
How common are GI problems among runners and endurance athletes, in terms of rough percentages of athletes who have some kind of GI distress during a race?
What is going on physiologically during intense exercise or dehydration that can cause gut issues?
Can use of any supplements or medications aggravate this issue even more?
Does exercise, and specifically a form of exercise like running, cause changes in your gut muscles or the way your intestines work?
Are these type of GI issues more prevalent in men or women, and if so, why?
What are the most common mistakes athletes make in terms of race day meal planning, and are there specific compounds (lactose, fructose, etc.) that should be avoided?
What do you think is the best carbohydrate fuel during exercise, and why?
Do you think there are any issues with gels and if so, are there better solutions, like blocs, chomps or jelly beans?
What about sucralose and other artificial sweeteners?
There are a variety of concentrated sport drinks on courses, such as Powerbar Performance, Gatorade, etc. Are these OK to drink?
Do you think that endurance athletes should be using electrolytes, or would you agree more with the philosophy of Tim Noakes that the body does a pretty good job maintaining plasma sodium levels? If we do use electrolytes, are certain forms better than others?
Any final tips that can be using in a pinch to stop GI issues?
So, what were some of my biggest takeaways and changes that I will personally make in Half and Full Ironman triathlons, based on this discussion?
1) During races, begin using green tea extract, delta-E, or 5 hour energy – rather than coffee or caffeine tablets.
2) During the run, switch a sucrose or glucose based solution, and avoid fructose/maltodextrin sources. I'm doing more research on this right now, because here are the current gel options on the market (notice that Clif uses “brown rice syrup” which is basically sucrose).
3) If I do use any Powerbar Perform or GU Brew drinks during an event, dissolve 3 parts water to 1 part solution.
4) Include 10-20g protein prior to races, or better yet, use a pre-digested aminos source such as MAP capsules
5) Avoid any electrolyte capsules or solutions that use chloride, and instead opt for carbonate, along with a trace minerals solution consumed during week of race and before race.
6) Keep Peppermint Tums on hand during run.