By Robert Kunz MS
Endurance athletes put a strong emphasis on their training programs, their equipment, and their nutrition to ensure they reach their goals. First Endurance consults daily with endurance athletes, primarily on nutrition and how to best fuel your body for long distance racing. Through the hundreds of consultations with beginners, veterans, elite amateurs and professionals, it is quite clear that carbohydrates and their correct usage is vastly misunderstood. How to fuel during endurance events is a hotly debated topic which we have tackled with clear recommendations.
Much of what is misunderstood is likely driven by the media’s generalization of nutrition topics. You often hear ‘eating too much sugar makes you fat and is bad for you.’ Even as an endurance nutrition company we often get asked why we have sugar in our drinks. Clinical data performed on the general population and/or mice, though valid within this constraint, becomes irrelevant for athletes who are exercising aerobically. In other words, the physiology of sitting on a couch sipping on sugar is far different than the physiology when we are out training. This has led to misunderstandings and misconceptions about carbohydrates. Below are the four most common misconceptions.
#1 Misconception: Sugars are high glycemic* so they give a sugar high then crash.
Glycemic Index is a test that measures the blood sugar response to a food after it has been ingested. High glycemic means the food quickly increases blood sugar, whereas low glycemic raises it slowly. Generalizing all sugars into the category of high glycemic is simply incorrect. From the chart below you can see that the simple sugars glucose and fructose are vastly different in their effect on blood sugar. Some sugars are high glycemic, some are moderate, and some are low. Almost all foods have been tested for glycemic index and can be found using a simple internet search. The only way to truly know what a food’s glycemic index is, is to look it up or have it measured.
Below you will find the glycemic index of the more common sugars found in sports drinks:
Glucose High
Maltodextrin High
Sucrose Moderate
agave nectar Low
Cyclic Cluster Dextrin Low (yet very fast gastric emptying)
Fructose Low
Glucose Scale 0-100
#2 Misconception: Complex Carbohydrates like Maltodextrin are slow burning
This is one of the most common misconceptions and is also directly related to misconception #1 & #4. Maltodextrin is one of the highest glycemic index carbohydrates available. Because it has a high glycemic load, it actually works very well as a primary carbohydrate in energy drinks. Additionally, maltodextrin has a low osmolality which allows it to empty from the gut faster – another reason of why it is an effective carbohydrate to consume while exercising.
#3 Misconception: Sugar is bad for my health.
What this should state is: Highly refined (empty calorie) high glycemic sugar during rest is bad for my health. Consider that fruits and vegetables and grains are primarily sugar, would one state that adding more vegetables, fruits and whole grain to one’s diet is bad? Of course not. Unfortunately, many consumers forget that these highly nutritious foods are almost all sugar. Sugar (as glucose) is the primary fuel that your body and brain runs on. Glycogen is our stored energy source and glucose is our circulating energy source. Nutrients like protein and fiber, and in extreme and rare cases even fat get broken down into glucose so your body can run efficiently. Trying to eliminate sugar is like trying to run your car without gas.
So what is bad about sugar? Consuming a high glycemic highly refined food when you are hungry causes a sugar high, strong insulin response, then a sugar crash. This ultimately can lead to insulin resistance and diabetes. This also causes consumers to eat more because with each sugar crash they crave more food. However, during exercise our physiology is different. While at rest your insulin works efficiently to bring high circulating glucose down. While exercising, the body wants the high circulating blood glucose to be driven to the working muscles as fuel. Hence, insulin is blunted while exercising, so eating a high glycemic food does NOT result in a sugar crash like it would at rest. TIP: Adding a low glycemic nutrient like protein or fat or even another low glycemic carbohydrate can lower its glycemic index and would therefore reduce the unwanted sugar high/low cycle.
Example#1: taking a couple handfuls of Rice Chex (GI=89), a short time later you feel emptiness (due to the sugar crash) and repeat the cycle. This leads to numerous health problems like insulin resistance, diabetes and weight gain. Let’s be clear here that it is not sugar that is the culprit but a high glycemic choice while at rest**. Now if you added some protein or fat to that snack choice, like nuts or an avocado, you have effectively reduced the glycemic index and will not get the sugar high/sugar crash result.
Example #2: You choose to have a piece of gluten free wheat bread (GI=90). Sugar high, sugar crash…repeat. Most don’t associate gluten free bread as being a bad choice but then again most don’t clearly understand the implications of glycemic index. Add a bit of peanut butter to the bread which is primarily protein and fat and you have reduced the glycemic index and hence stabilized blood sugar.
In these examples you can clearly see that it’s not the sugar that is the culprit in bad health but the high glycemic choice. In both examples you can consume the same amount of sugar, yet #2 is low glycemic and will therefore stabilize blood sugar.
#4 Misconception: Since I am doing a long race, I should consume slow burning carbohydrates
In the opening paragraph we stated that clinical data on the general population does not extrapolate to endurance athletes. From the misconception #3 you
should have learned that high glycemic foods result in a sugar high and sugar crash. This is true in all situations EXCEPT when you are exercising and immediately following. Many athletes have taken what they learn from the media and have concerned themselves with consuming sugar and hence opted for a more sustained energy flow coming from maltodextrin (a complex carbohydrate). Their reasoning of WHY they chose maltodextrin is wrong on three counts.
1) As stated above, when you are exercising your insulin is blunted. Meaning, that when you are exercising and you consume a high glycemic food, you do not get a strong insulin response and hence you do not get a sugar crash. Your body is very smart and it clearly understands that when you are exercising you want to use the food or drink you consume to fuel your muscles. If insulin kicked in, the food or fuel you consumed would not get to the working muscle.
2) Athletes tend to choose maltodextrin, which is a good choice, but do so for the wrong reasons. As you learned from misconception #1 maltodextrin is actually high glycemic not low glycemic. Hence maltodextrin is a good choice because it is fast absorbing, not because it’s slow absorbing.
3) Looking for that low glycemic, slow sustained energy will actually cause you to bonk prematurely. Some even consider using some fat because they are going long. Understand that we all have about two hours of stored glycogen. Once this runs out, we bonk. If you consume a slow absorbing/low glycemic food while exercising you are forcing your body to rely on its stored glycogen. The entire goal of fueling for long endurance racing is to spare your muscle glycogen. In other words, do what you can to hold on to that stored glycogen. The best way to accomplish this, outside of appropriate pace and training, is to consume primarily fast absorbing carbohydrates to fuel your exercise. This will allow you to immediately use what you consume for the working muscle, so you can spare your stored muscle glycogen.
The act of consuming slow nutrients can also cause gastric distress. Consider that slow absorbing nutrients spend a lot of time in the digestive system. Doing this while exercising simply backs up the digestive system and does not allow for those fast nutrients to get absorbed. Often athletes cannot understand why they bonked when they consumed a large amount of calories. The simple answer is that they likely consumed slow calories that did not absorb before their glycogen ran out and often you feel this through considerable stomach discomfort.
notes:
*Glycemic index is the measure of your blood sugar response following the consumption of food. High glycemic foods result in a sugar high. Low glycemic foods are absorbed more slowly and result in a steady blood sugar response. Adding fat, protein or fiber to any food effectively reduces its glycemic index. Though there are two scales used, the more common scale measures glycemic index from 0 to 100.
**While at rest your insulin works efficiently to bring high circulating glucose down. While exercising the body wants the high circulating blood glucose to be driven to the working muscles as fuel. Hence, while exercising, insulin is blunted and therefore eating high glycemic food does NOT result in a sugar crash.
Resent research has proved that during exercise carbohydrates can be absorbed concurrently in multiple channels. Consuming several carbohydrate sources will allow the endurance athlete to better absorb the fuel needed to sustain endurance activity.
Great article. It is nice to see that we are on the same page.I will post it in the racelab page to reinforce what I have been telling my athletes :-)
I hope things are going well for you and the company.
Best regards,
Bettina (racelab)
Thanks Bettina.
It took dozens of nutrition talks and consultations with a varied athletes that I came to realize how widely misunderstood these carbohydrate concepts are. Do you find the same thing with your athletes?
Hi Robert,
I give a monthly nutrition clinic to my athletes, so they learn this from the beginning. What I’ve noticed is that way too many athletes read some article and adopt very extreme nutrition habits, without understanding the concepts of what they are following. That is sometimes scary :-)
Robert,
This was a great article. I’m going to save it so I don’t forget.
Any chance you or any members of the First Endurance team will be speaking in SLC anytime in the near future? It would be great to have an evening of hearing more about this sort of thing.
Robert,
I’ve switched to EFS after having a horrible experience at the Leadville 100 while using one of your competitors endurance drinks. I love the taste and drink more of it, but am concerned about the amount of calories per serving. Is it enough? I hope to test it out on a 100 mile ride this spring. I’m 44, 5’11” and weigh 160 lbs. I’m in excellent shape. I’m concerned I won’t receive enough calories/carbs from a single serving per hour. Your comment will be greatly appreciated.
Thank you,
Bill
Great article ! What still amazes me is that most brands still insist on including large amounts of fructose in their products. If you are looking for GI issues during a race, look no further than fructose, it really is the devil of sugars. Perhaps one day the likes of Powerbar will realise that a combination of maltodextrin, dextrose and sucrose is far more effective ?
It would be great to see companies at some point, including FE, using maltodextrin from non-GMO corn.
Thank you for the informative article.It has cleared a few things up.
Great article, Robert – very informative. Thanks. But I have one question. I hear the phrase “empty calories” sometimes and you use it above. How can a calorie be empty? If it’s a calorie, then you can burn it for energy, correct? Or it gets stored as fat and you can burn it later. So, what does it mean to be an “empty calorie”?
BIll,
Great question about the empty calories. What we mean here is empty of ‘other beneficial nutrients’. IE the sugar from a coke has no nutrient value except the 4 calories per gram. The sugar from an Orange is packed with healthful micro-nutrients like antioxidants, vitamin C and such and also 4 calories per gram. I probably could have explained this a bit better in the article.
Pure brilliance here. You chose your words carefully, providing a lucid explanation with scientific evidence. Your products work flawlessly and you have the data to back up the success. As someone who is both an endurance mountain bike racer and former research scientist, I appreciate your products on more than one level.
OK, I’m an endurance runner but not a nutrition expert. Help me translate this into real foods at the aid stations. There are cookies, gummy bears, PB&J sandwiches, M&M’s, various fruits, potato chips, cheezits, coke, redbull, etc., etc… What does one eat to get the most benefit to the body, and to the next aid station while keeping the stomach happy along the way? Also, what is good to place in the drop bags that will not spoil over a 30-36 hour 100 miler?
@Michael-Hilarious, dude! But what a great question. If you have support folks, you can stash First Endurance products in musette bags and leave them. If you don’t have your own support crew, most endurance races have support crews that will work with you.
Heidi – Not Hilarious! Most runners do not have support crews 100’s of miles from home and very few of the aid station personnel are nutrition experts (just everyday volunteers). They refill your water and keep the M&M’s full. As you know, drop bags are often limited. Yes, one can stock up on First Endurance products in a drop bag, but without doing a commericial for First Endurance, what are the best items “on the aid station table” to help get one through a race?
@Michael-Hilarious only by virtue of being so viscerally true. I don’t mean literally hilarious. I fight the same issues you do which is why your question is so good.
Michael,
As I stated in the article many foods have a glycemic index which can be looked up by simply googling glycemic index scale. Its not as easy as guessing its high. For example instant oat meal is high glycemic whereas slow cooked oat meal is relatively low glycemic. So the only way to tell is to look things up. Do know that anytime you add protein, fat, fiber to a food you have effectively lowered its glycemic index, so typically ‘sugary’ snacks are higher GI than non-sugary snack but then again this is not always true. SO from the foods you listed M& M’s without nuts are higher glycemic than M& M’s with nuts, though both have some milk fat that will slow its digestion. Heidi does offer a great recommendation to have some EFS drinks or liquid shot on hand. As I stated in the article it is no practical or always feasible to always consume high glycemic foods or EFS for that matter, but if you can focus the majority of your calories this way you should find greater success. One tried and true food that tends to work well is Coke..high glycemic and many athletes do well drinking this on the latter parts of their long races.
Another way to look at it is, focus on limiting fat, protein and fiber…what remains is various sources of carbohydrates. Sticking true to my last footnote, mixing carbohydrate sources does work well because they can get absorbed in multiple channels.
hope this helps.
Robert – Like I said to begin with, “I am not a nutrition expert”. I cannot tell a glycemic from a fat from a carbohydrate. I eat, I run, I bonk (or not)! I have no more of a clue what to grab off the table now than I did before. I’m still confused!!!! As an expert in nutrition, it would be great if you could communicate to the average runner in terms we can understand by associating actual foods by name or brand (or snacks on the table in many cases) with what you are trying to explain. Your expertise would be much more useful if related to real world avarage runners who want to know “What to Eat”. BTW – Oatmeal is not on the table, but the other items I listed are. It’s just a matter dumming down to the avarage runner in our terms, not yours.
Great article! I have long thought that a food’s GI was a more pertinent matter than is commonly discussed, and I appreciate the information. My concern is, when I am running all day long, I get tired of just carbs and my body craves some food with more substance, such as protein. What is the best way to integrate protein into your nutrition plan for an ultra, and what is the optimal amount or ratio to be ingesting for continued endurance in very long runs?
Michael,
I understand what you are saying. The GI of a food or snack can differ dramatically based on brand alone, so its difficult for me to comment on ‘potato chips’ or ‘various fruits’. Please refer to this list using the scale on the right ‘glucose scale’. Scroll down. Stick to the higher numbers while exercising and for recovery and lower numbers to stabilize blood sugar during the day.
http://www.mendosa.com/gilistold.htm
Robert – OK. Now we are starting to talk the same language. I can look up the “generic items” on the table and get a feel for which would be rated higher. Not an exact science but in the ball park for starters. Also helps to identify some items that might be good for drop bags (other than First Endurance products of course). May get back to you once I have a chance to digest this list. Thanks, Mike
Chele,
I’ve used some First Endurance Ultragen for during workouts or races over 8 hrs long.
My athletes use it too and it works really well. Of course I recommend starting with small amounts or maybe a little diluted.
Robert…do you have a comment on this…does it make sense? It has worked well so far!
Bettina
Chele,
When running all day long consuming straight carbohydrates can no doubt cause taste fatigue. Some also claim that they don’t like the feel of an empty stomach all day. Some even say just a bit of solid food helps ‘settle’ their stomach. My recommendation is to offer a bit of solid food, or protein in small amounts dispersed throughout the day. Make sure to follow the food with ample water and if at all possible do so in sections where the effort is on the lower end. This allows for more blood to the stomach to help digest the food. Taking small amounts with water also assures you don’t get backed up. I would not be too concerned with ratio’s, but do recommend you stick to foods or snacks that you typically eat so your body is ‘used’ to this substance.
Bettina and Chele,
Yes, many have used a serving or two of Ultragen in Ultra runs with great success. Some use the EFS bar (which will be back in stock again this Spring) also with great success. I did try to imply in the article that the recommendation is to consume ‘primarily’ fast absorbing nutrients to assure your muscles are getting a steady supply of fuel. Every so often consuming a solid food or snack that is not so fast to absorb can be OK, but do so sparingly and spread it out so its not all coming at once.
Robert,
Could you expand a bit on this paragraph?
‘Resent research has proved that during exercise carbohydrates can be absorbed concurrently in multiple channels. Consuming several carbohydrate sources will allow the endurance athlete to better absorb the fuel needed to sustain endurance activity.’
What is meant by ‘multiple channels’?
Dr. Jeukendrup through several studies looked at the absorption rate of different carbohydrates. He also looked at what happens when combining carbohydrates. When combining carbohydrate sources the absorption rates, or more specifically the oxidation rates increased, meaning carbohydrates were able to be absorbed at a higher rate. Dr. Jeukendrup theorized that this happens because different carbohydrates can get absorbed concurrently in different areas of the digestive system which effectively allows you to absorb more at any one time. The take home message is ‘mixing carbohydrate sources increases the quantity that can be absorbed over any single source’.
Great explanation!
Robert, I have a question…but I don’t know if you want to get into that topic in this blog.
What do you think about the high fat, no carbohydrates diets that many athletes are adopting now? I’m very skeptical!
Bettina
Bettina,
If you are referring to adjusting substrate utilization, or what we call Low Cho Training, then we address it here. This article explains the concept and shows athletes how to do it right. http://team.firstendurance.com/page/low-carbo-training
In a nutshell, it can be a nice tool to adapt an athletes ability to burn fat more efficiently but it has to be done right or the athlete will suffer consequences of poor recovery and poor energy levels.
Ok, another question. I just finished Dean Karnazes’ book, 50 Marathons in 50 Days, in which he suggests adding in protein, such as in Accelerade, in a 1:4 ratio with carbs, for improved endurance and muscle retention/recovery. Can you speak to that subject?
Chele,
Protein is good to use during exercise in that it improves glycogen resynthesis and improves central fatigue (fatigue of the nervous system). The issue with protein again is that it is slow to absorb and it can cause issues in your gut. The best way to get all the benefits of protein without the downside is to consume the free form amino acids inherent in protein. These free form amino acids like glutamine and branched chain amino acids offer the same benefits, but because they are much smaller molecules they are easier to absorb while exercising. We actually covered this entire subject in a previous blog post.
http://www.firstendurance.com/2010/10/free-form-amino-acids-vs-complete-proteins/
Wow, thanks! That is exactly the info I was looking for. In fact, the difference between protein and BCAAs, which I have already been using, was going to be my next question. Next question: how do I know what would be the optimal amount of BCAAs to ingest per hour or per mile of ultrarunning?
Chele,
I’d like to think we did all this homework for you. We have 2g of BCAA/Glutamine per serving of EFS drink. Though the research is not perfectly clear because it is always hard to extrapolate clinical data to real-world situations like an Ultra run, 1-4g of free form amino acids per hour can be supported by the research. Now it is our position that these free form amino acids are beneficial, but realize that its the mix of high glycemic carbs and your electrolytes that should take precedence when mapping out your nutritional priorities.
Thank you! I have currently been using Melaleuca Sustain for electrolytes mixed with BCAAs and glutamine in my hydration pack, combined with Melaleuca Access shakes every 2 hours and some type of gu or gel every 40 minutes between the access shakes for carbs. Does this seem like an optimal nutrition plan for an ultra? It has worked well for me in training and marathons, and I will be running my first ultra this coming Saturday, so I probably shouldn’t make any severe alterations now, though I am always looking for continued nutritional improvement in the future, which is why I was wondering if BCAAs were adequate or whether I should additionally add in some type of protein. I have never tried any EFS products, but am interested in learning more about them.
Chele,
Our opinion on what is optimal is no doubt going to be biased. Of course we feel that a combination of EFS drinks with EFS liquid shot is ideal for ultra running and we have had many of the best ultra runners in the country use this with so much success they are breaking course records along the way. With your race coming up this weekend, I suggest you look less at what to add to your fuel and more at what to eliminate from your plan. Stick to the mix of carbohydrates and electrolytes as your priority and don’t concern yourself with adjusting or adding amino acids or proteins at this point. Stick to the basics..carbohydrates, adequate electrolytes and adequate hydration.
I recently attended a tri seminar where there was a guy talking about a supplement called Vespa (vespapower.com). Vespa, in short, helps metabolizes body fat into energy rather than the limited supply of glucose in our body. Therefore during a long endurance event the amount of EFS Shot (or other gel products) can be reduced. Sounds a bit hokey to me. Can you explain this in better detail?
Mike,
Thank you for your comment on the VESPA product. Though their explanation of the physiology associated with metabolizing fat more efficiently is correct, I have not seen the clinical studies on their claimed amino acid mix that does this. There is a niche-shift to changing your substrate utilization to utilize fat more efficiently and ultra long distance athletes can benefit by adapting to this change, but I am not aware of substrates that do this for you outside of the early research on caffeine which showed it to mobilize free fatty acids. We do touch on the subject of substrate utilization here.
http://team.firstendurance.com/page/low-carbo-training
Thanks, very well writing article, and great information.
Keep up the great work :)
Ruunner1
what is FE opinion on new age resistive starch products that have super low osmolality, causes no gi distress and promises very stable glucose levels.
I am an ultra triathlon participant and would like to know if there is an opinion from FE on this product.
Janis,
We are fully on board with the super starch that is now available on the market, however we urge buyers to look closely at what they are purchasing. Not all of these super starches are equal. There is only one cyclic cluster dextrin that is 100% soluble in water and that relates to the research available. Several of these products are insoluble (they gum up in water) and incorrectly stating data regarding this starch.
Our new EFSPro product uses the fully soluble cyclic dextrin as the primary carbohydrate in the formula. We further improved this drink by adding L-alanyl L-glutamine which improves the absorption of water and minerals in the gut. In addition there is 1,400mg of electrolytes per serving. http://firstendurance.com/nutrition/home/efspro.html
So if I plan to compete in a 6 to 9 hour mountain bike race is a sports drink like Scratch with only simple sugars good? I have been using that primarily in 6 hour races and have had good results.
Skratch works well when used as designed. Which is as a light calorie drink. If you try and push more calories the simple sugars have a heavy osmolar load and would then become problematic. At 6 hours of racing you are probably at the limit of your ability to consume a ‘light’ calorie mixture that gets absorbed well. Realize that 1/2 strength EFS is very similar to a full strength Skratch drink, however it delivers even more electrolytes, amino acids and its at a lower osmolar load and price.
http://firstendurance.com/efs-vs-skratch-labs-vs-osmo-an-electrolyte-hydration-drink-comparison/
Thank you, Robert, very nice article. However there is one point on which I’m sure you misspoke. You say
“ALL nutrients, including fat or fiber, ultimately get broken down into glucose so your body can run efficiently.”
But this is certainly not the case; fat cannot be converted to glucose. It is burned via beta-oxidation in the mitochondria. I’m assuming this was a simple oversight?
Bob,
You bring up a good point and maybe something that is beyond the biochemistry that was intended for this article. There is evidence and an argument that through the ketogenic pathway some glucose can be produced via fatty acids, though the process is highly inefficient and requires one be completely depleted of glycogen. So, for all intensive purposes the article is correct but likely a bit misleading since the conversion to glucose is typically unlikely. I will therefore take this comment in stride and will offer a edit to clarify.
Thank you Robert. Sorry to nitpick; it just jumped out at me.