Tri Talk Triathlon Podcast, Episode 49

 Research behind a high calorie/low risk race nutrition strategy, the common causes of GI problems, and what it’s like to go from athlete to race manager.

Welcome to Tri Talk, your podcast source for, triathlon tips, training, news and more. New listeners in the last 2 weeks primarily came from China, no doubt in part as a result of the announcement of Ironman China in 2008, as well as the 2008 Olympic games. It makes sense that interest in triathlon in China would certainly be on the rise. Also of note, welcome to the very small new group of listeners from Vietnam. My goal at Tri Talk is to help you swim, bike, and run faster, to meet your personal triathlon goals. Whether you are an elite or amateur triathlete, we cover sprint distance to Ironman distance. I’m your host, David Warden, and this is Tri Talk episode 49.

Lots to cover today on Tri Talk. For example, have you ever been training or racing and found yourself incapacitated with stomach problems? Or worse, have you found yourself reducing your intake to address the problem, only to find yourself bonking at the end of the race? How much can you take in, and does the type of carbohydrates matter? What are the common causes of gastrointestinal problems, and how can you avoid them? We’ll take a look at all of that. Plus, what’s it like on the other side of an endurance event, as a race manager? I’ll take you along with me as I try my hand at running an event as opposed to running at an event.

Now, as we approach the landmark 50th episode of Tri Talk, did you know that there is over 17 hours worth of episodes available? If you discovered Tri Talk late, you might have missed some of the earlier discussions on the physics and physiology of triathlon. But if you missed those episodes, doesn’t that mean the triathletes who did listen to them and applied the concepts will be faster than you? That’s what you call “scare tactic” marketing! Seriously though, if you missed half of the Tri Talk episodes, does that mean your competition who did hear them will be twice as fast? Probably not, but I wouldn’t take the chance! Be sure to visit and access the Tri Talk Episode Archives and get caught up on your favorite triathlon podcast.

Let’s get onto the good stuff! What do you do when the estimated required calories per hour exceeds your estimated ability to absorb that many calories? Just how many calories can you take in without the risk of GI problems?

This next section will apply primarily to Ironman and half-Ironman athletes, but for the rest of you, this is still relevant and fascinating information. Even if you never plan on racing at those distances, this will increase your knowledge of endurance nutrition, and you will sound really smart when you talk smack with other triathletes.

I have said this before, but I’ll say it again. Triathletes are the smartest set of athletes in the world. After episode 45, where I introduced the Tri Talk Nutrition Calculator, several of you pointed out that at certain distances or intensities, particularly Ironman and half-Ironman distances for male athletes, the total calories per hour recommend often exceeded 400 calories. Several of you pointed out that there has been considerable material that supports that the maximum amount of carbohydrates that can be absorbed and returned to the muscles was 1.5 gram of carbohydrates per minute, or 90 grams per hour. Since carbohydrates have 4 calories per gram, that would place a theoretical limit of 360 calories per hour that the athlete could take in without risk of gastrointestinal (GI) problems. Eventually, the intestines and stomach could back-up if you are eating more than you can digest.

This information was based on an excellent study published in 2000, and has been cited as the primary support behind that 360 calorie per hour limit. The conflict with the study, is the fact that many athletes take in more than 360 calories per hour without reporting GI problems. In fact, Joe Friel’s Training Bible recommends up to 700 calories per hour on the bike for Ironman racing. This is an excellent example of when the science did not match the race-day realities. How can this study be reconciled with the actual calories that Ironman athletes take in that often exceed 360 calories per hour?

The first thing to note about this study is that the researches used a pure glucose solution when determining that absorption limit. There are multiple forms of carbohydrates including glucose, sucrose, dextrose, fructose, maltose, and my personal favorite galactose. I just love the name, “galactose”.

Fast-forward to 2003. A set of the same researches said, “hey, what if we make a carbohydrate cocktail of multiple types of these sugars, instead of just straight glucose?” Using the same protocol as in the study 4 years earlier, they created a mixture of 2 parts glucose to one part sucrose. With that mixture, the athletes were able to absorb 1.8 grams of carbs per minute without significant GI problems, upping the hourly intake to 432 calories per hour (1.8x4x60).

But they didn’t stop there. In a 2004 study, a set of the same researchers then took a mixture of 3 types of sugars, 2 parts glucose, 1 part sucrose, and 1 part fructose. Using the same protocol as the year before, which was a 2.5 hour ride at about 77% MaxHR, the cyclists were able to absorb a whopping 2.4 grams per minute. That’s 576 calories per hour!

The theory behind this is that different carbohydrates are absorbed by different intestinal transport systems. Some digestive receptors may get saturated by glucose, but other receptors or transport systems that don’t transport glucose, will process the other types of sugars, like fructose and sucrose. It is interesting to take this theory even further and hypothesize that maybe this is why small amounts of protein in an endurance event can improve performance. Although the body does turn to protein in small amounts for fuel after long endurance events, is it possible that there are even more receptors or transport mechanisms that would absorb even more than that 576 calories if another 50 calories of protein per hour were taken in? This is total speculation on my part, I have not read anything specific to this theory, but it follows the hypothesis that if a variety of sugars can increase absorption rates, perhaps a variety of macronutrients, like carbs, protein and even fats in a nutrition strategy can maximize absorption. I wonder if that is the difference between the athletes who take in 400 per hour calories and have GI problems, and the athletes who take in 600 and do not. I’m sure individual tolerance for calorie volume varies, but what if the athlete experiencing GI problems is taking in nothing but energy gels, which may only have 1 or 2 types of sugars. While an athlete taking in 70% carbs in the form of multiple sugars, 20% fats in the form of MCTs, and 10% protein would be able to take in relatively large amounts of calories without GI problems because now they would involving multiple digestive receptors and transport mechanisms instead of just one or two. In addition to increased calorie intake, there are other advantages from taking on more than just sugars which I will discuss in a moment.

It is important to note that most athletes can tolerate less on the run than on the bike, not due to absorption per se, but rather the jostling of the stomach that takes place during the run. All 3 of these absorption studies were done on cyclists, and it is common to take in a lot less on the run, maybe 2/3 of what you took in on the bike. Although a 2002 study of Ironman finishers showed that performance in the marathon portion of an Ironman was directly proportional to the amount of calories taken in. The more calories you can tolerate on the run, the faster you will be able to go.

There are many topics that are just too complex for me to research on my own, and this was one of them. I want to thank Ellen Coleman and Bob Seebohar, Melanie Hingle from the University of Arizona, Dr. Bill Thompson of Florida State University, and Dr. John Martinez of the Coastal Sports and Wellness Medical Center in San Diego. I could not have brought you this information without their help.

Now, let’s take a few moments and discuss the causes and consequences of lack of absorption when taking in high simple sugar calories, and what can be done in addition to the strategy we just talked about above to avoid those problems.

There are three primary causes and consequences for taking in more than you can absorb.

The first is diarrhea. Drinking a ton of simple sugary fluids or taking on a ton of gels with water can cause fluid to be drawn from the bloodstream and directly into the intestines. This speeds up the digestive process, resulting in diarrhea. What is even worse about diarrhea is that is again leads to dehydration, and the athlete may begin to take in even more fluids with sugars. This can be avoided by ingesting a lower volume of simple-sugar-containing fluids.

The second consequence is called delayed gastric emptying or DGE. This is simply the body not able to absorb as much as you are taking in while exercising. It makes the athlete feel boated and full, or even sharp pains in the stomach. This can be avoided by using a nutrition strategy that allows for complete absorption of what is taken, as we discussed earlier. Also, environmental conditions such as high heat and humidity can negatively affect the rate of gastric emptying and promote even more discomfort. This is something you would want to test while training, but it is common for you to not be able to tolerate as much intake when it is hot or humid, and you may have to adjust your intake accordingly.

Finally, there is one more symptom of taking in too much simple sugars. Let’s be polite and call it “flatulence”. After passing through the small intestine, some sugars reach the large bowel where they become food for the bacteria living there. When the bacteria digest the sugars, they produce of gas. This too can cause cramping, bloating, and flatulence.

By the way, the Tri Talk Nutrition Calculator is now in its second beta release thanks to your feedback, and you can put in your data to find out the calories per hour you need for your upcoming event.

I would like to take just a moment and revisit the altitude training issue which has been discussed twice now on Tri Talk. I really don’t want to ever discuss a topic more than twice, and even then I cover it a second time just to clarify or correct a previous episode. But I have done a considerable amount of new research on this subject. As a compromise, instead of adding it into a Tri Talk podcast episode, I have added it as an article on the web site where you can read the whole story on altitude training. I encourage you to take some time to read this. I hope it is the beginning of what will become the definitive discussion on altitude training. Also on this subject, a correction from episode 44. In that episode I stated “…because the air is less dense at higher altitudes, you are able to ventilate greater volumes of air, and get in the oxygen you need…” This is not correct, although ventilation does increase to compensate, at high altitudes, you do not get the same amount of total oxygen as lower altitudes.

Let’s wrap thing up! Almost all of us have participated in some sort of athletic event. Maybe even a few of us have volunteered to help at an event. If you are one of those who have ever volunteered for an event, you belong to a special class of people. But have you ever been in charge of an event, or a portion of an event? By the time we get to the race, it usually seems so smooth and well put together (usually). What do we all get for our $50 in registration fees, and how much work goes into it behind the scenes? Come with me as I take you along with me live, as I go through my first experience of managing a race complete with course setup, training volunteers, and as it turns out, a little bit of crisis control.

Take 11 of your friends, put them in two vans, and spend the next 20 hours or more taking turns running a course almost 200 miles long. That is the concept behind the Ragnar Realy Race series. Each 12-man team takes turns running 3 legs ranging from 3 to 8 miles each. I participated in the event in 2005, and it ended up being one of my most enjoyable racing experiencing. It felt like an adult slumber party. It took our group 22 hours to complete the event, but I spent less than 2 hours running my 3 legs, leaving the other 20 hours for conversation and goofing around with my teammates. With Ragnar events now in Wisconsin, Washington, Arizona and Utah, the popularity and growth of the series reflects its unique racing experience.

There are 35 exchange points along the route, where one runner hands-off to the next runner, and so it continues for 200 miles. As you can imagine, one of the challenges is, how can you manage and support the runners over an equivalent of 8 marathons back-to-back? The answer, of course, is delegation. That’s where I come in. The event is the Ragnar Great River Relay, running from LaCross, WI all the way to downtown St. Paul, Minnesota. I’ll be managing the last 6 exchange points of the event, from exchange 30 all the way to the finish line, or about 30 miles. My evening started at 10:00 on a Friday night, and I spend the next 5 hours putting up signs and lights for every single turn over 30 miles, and setting up the 6 exchange points. At 3 in the morning, I’m finally finished setting up in St. Paul, and my day has only begun.

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Each of the more than 100 teams in this event has brought 3 volunteers to the table. I’ll be moving from exchange point to exchange point training the volunteers over my part of the race. I meet my first group at 4 am, or about 2 hours before the first runners begin coming through.

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It’s a training I’ll repeat for all 6 exchanges. By 6 am, things are running almost too smoothly. The volunteers are showing up, the course signs aren’t being stolen, and there are no reports of injuries or missing runners. But then, my first test arises. It turns out that at the very same time, on the very same course, and using the same exchange point, there is a cancer awareness walk with thousands of walkers. I receive a call from a panicked Ragnar volunteer that a passionate volunteer for the cancer walk is at the site insisting we can’t share the exchange point. Also of concern is the fact that some of the route we share is on a narrow trail, and congestion and safety could be an issue as our runners are flying by the walkers. Fortunately, as I escalate the issue up the chain, I talk to the regional director of the group, and we agree to make the exchange point a celebration of athletics and cancer awareness, by merging our volunteers together into one unit. It is a great example of what can be done when people focus on solutions, and not the problems. A few calls to my volunteers about the logistical changes, and the issue is sorted.

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I quickly realize that race management is not about eliminating surprises, because it just isn’t possible. It is about adapting and making quick decisions regarding the inevitable crisis that will occur. What started out as an easy morning, has turned into call after call from volunteers or runners, coming in so quickly one after another, it’s almost comical.

With the excitement of the exchange point crisis, the phone calls, plus a lack of sleep, its no wonder I haven’t been paying attention to the road, and I realize that I am lost. I last drove this part of the route in the middle of the night, and things look quite different in the day.

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Fortunately, I quickly find my way back and finish training the last sets of volunteers. Driving the route from the last exchange point to the finish line, I notice that one of the signs is missing. Driving further, I see that all the signs coming into downtown have been removed. The original route had the runners run beneath the I-35W bridge. After the collapse, which took place just 3 weeks before the event, the route was routed over a different bridge. It appears that all the signs for the runners from that point on have been removed. In a panic, I call Dan Hill, the head race director of the event.

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A veteran of these events, Dan kindly asks me to triple check that I am on the correct route, and perhaps the error is with me and not the signs or cones. Somewhat insulted, I drive back, get out my map, and realize that he was exactly right.


Throughout the morning, as runners are now hitting the exchange points in greater numbers, I begin to get even more and more calls from the volunteers and runners asking for help or clarification.


After driving the length of the course again and dropping off some equipment, I decide to head down to the joint Ragnar and cancer awareness exchange point to see how our compromise has been working out, and meet the cancer awareness event manager running the site. Things have gone so well that we end up falling all over each other with compliments.


Apparently, everything is going “great”, since I repeated that word at least 6 times in the conversation. Finally, as the last runners comes through each exchange, its time to sweep the course behind them. I spent the next 6 hours taking down the signs, picking up garbage, and thanking volunteers. I’m already exhausted. At the finish line, I continue to help take down the signs, tents and pavilions. After loading up the vans, and heading out to a celebratory dinner with the race management team, I finally get to bed at 2am Sunday morning. I haven’t slept in 44 hours, but I am thoroughly satisfied that my actions of the last 2 days helped to execute an almost flawless event for a group of fellow athletes, and I hope it will be a fond memory for them. In the 20 seconds between the time I hit the pillow and fall asleep, the thought occurs to me that I may never have been this tired in my life. My next race is the Boston Marathon in April, as a runner, not a volunteer. At least my next event won’t be so exhausting. This is David Warden, for Tri Talk.

 Thanks for sticking with me to the bitter end of the podcast. Special thanks to the Ragnar Relay series for letting me volunteer to manage the course. You can find out more about their events at If you listen to the show via iTunes, you may have noticed that Tri Talk is now the #4 featured podcast in all of iTunes Sports and Recreation, ahead of the thousands of other sports podcasts including all but one ESPN podcast.