Canadian PowerBar athlete Reid Coolsaet recently ran his best-ever marathon, clocking in at an Olympic-qualifying time of 2:11:23. What's remarkable about this story is not only that Reid's time is the fastest marathon ever run by a Canadian on Canadian soil, but also that he accomplished the task while using a fueling plan — a sports drink/energy gel/water combination — that was over a 10% carbohydrate concentration (grams of carbs/ml) instead of the 6–8% carbohydrate concentration range that endurance athletes are generally advised not to exceed.
According to Reid's nutrition/fueling advisor, Trent Stellingwerff, PhD, this fits the pattern of more and more elite endurance athletes' refueling and rehydrating with carbohydrate concentrations that exceed the 8% limit during endurance competitions and training sessions. We realize that many factors play into athletic performance and that having a solid fueling plan is only part of the big picture, but still it plays a very significant part.
Two other athletes Trent works with have similar stories: Dylan Wykes won the recent California International Marathon with a time of 2:12:39 using a 10% carbohydrate solution while racing, and fellow Canadian Eric Gillis ran a 2:12:08 marathon this past fall utilizing a 12% carbohydrate fueling plan during his run.
According to Stellingwerff, "That makes three homegrown Canadian lads who have been under 2:13 recently, and all have accomplished the task while fueling with
PowerBar® C2MAX dual source energy blend carbohydrates at concentrations of 10% or higher." The impetus behind the push for a higher concentration of carbs during endurance exercise is cutting-edge research showing that a combination of glucose and fructose — the carbs in
PowerBar C2MAX — not only increases the delivery of carbohydrate fuel to exercising muscles but also enhances the emptying of fluid from the stomach and the absorption of fluid.(1)
Reid Coolsaet:
52g PowerBar
® C2MAX dual source energy blend carbs/hour mixed into
~460 ml water/hour (~11% carbohydrate solution)
Previous best marathon time: 2:16:53
New PB: 2:11:23 (Scotiabank Toronto Waterfront Marathon)
Dylan Wykes:
70g PowerBar C2MAX carbs/hour mixed into ~700 ml water/hour
(~10% carbohydrate solution)
Previous best marathon time: 2:15:15
New PB: 2:12:39 (California International Marathon)
Eric Gillis:
57g PowerBar C2MAX carbs/hour mixed into ~480 ml water/hour
(~12% carbohydrate solution)
Previous best marathon time: 2:13:56
New PB: 2:12:08 (Scotiabank Toronto Waterfront Marathon)
A Question of Balance
The fact that carbs and fluids during endurance exercise can boost performance is nothing new. If you go back into the annals of published sports nutrition literature, you can find all kinds of studies indicating that a combination of carbs and fluids while competing can help extend endurance and improve performance for endurance athletes.
The challenge for athletes has been to find the right balance or concentration of carbohydrates and fluids when competing or training. Too low a carbohydrate concentration can mean that you don't get a full performance boost when you need it; too high a concentration can lead to a belly full of aches. That's why the conventional wisdom, sanctioned by the
American College of Sports Medicine, has been to consume a carbohydrate concentration — sports drink and/or energy gel plus water, for example — in the range of 6–8%.
Multiple transportable carbs drive the new trend
The concept of
multiple transportable carbohydrates is an innovation captured by PowerBar C2MAX that boosts both fuel and fluid delivery.
The recommended 6–8% carbohydrate concentration range stems from studies in which only a single carbohydrate source — such as glucose or maltodextrin — was fed to athletes during endurance exercise. Not fully appreciated at the time was the finding that absorption of carbs from the digestive tract is facilitated by specialized transport molecules. Think of these transporters as cars on a commuter train. Once a car is packed with passengers, it simply can't hold any more. The remaining commuters have to wait for the next train.
Carbohydrate transport from the gut is similar. Once a carbohydrate transport molecule is packed and loaded with its specific carbohydrate — glucose from your sports drink or energy gel, for example — the transporter simply can't take any more. Any remaining glucose must wait in the gut for another transporter to become available. However, it turns out that these carbohydrate transporters are not one-size-fits-all. Instead, glucose and fructose have their own separate transporters. With this knowledge in hand, it didn't take scientists too long to figure out that by feeding multiple transportable carbohydrates — both glucose and fructose — during exercise, more transporters could be called upon for carbohydrate absorption. And that in turn can lead to an increase in the burning of ingested carbs by working muscles during exercise. In fact, new research shows that if a combination of glucose and fructose is provided during endurance exercise, the carbohydrate burn rate — scientists call it the
oxidation rate — can increase by 20–50% compared to when glucose alone is provided.
Of course, this would be all for naught if more carbs meant a slower emptying of fluids from the stomach, impaired hydration, or a greater chance of digestive upset. This is what was shown with single carbohydrate sources. Instead, the opposite seems to be true of blends of multiple transportable carbohydrates, which seem to speed both the rate at which fluids are emptied from the stomach and their absorption, with a tendency to decrease rather than increase the risk of gastrointestinal side effects.
PowerBar C2MAX: Science in Action
Applying the multiple transportable carbohydrate concept to sports nutrition products is what led to
PowerBar C2MAX. PowerBar
® products with PowerBar C2MAX provide a 2:1 ratio of glucose to fructose that takes advantage of the fact that each of these carbohydrates has its own unique transport system. And published research has now shown that when compared to taking in the same number of total carbs from glucose alone, PowerBar C2MAX carbs can produce an 8% boost in endurance performance.(2)
Is an increased carb concentration fueling plan right for you?
If you run in the same circles as Reid, Dylan, Eric, or other elite endurance athletes competing for a shot at the Olympics or something comparable, pushing the envelope on carb concentration during training sessions and competitions is something to consider.
To give you a picture of what an increased carb concentration fueling plan can look like, the following are the plans used by Reid and Dylan in their respective marathons.
According to Dr. Stellingwerff, there are also some important practical tips to keep in mind when boosting carbohydrate concentration during endurance exercise:
- First, if you are going for an increased concentration of carbs, multiple transportable carbs are key. If you try to use glucose alone, chances are good that a concentration exceeding 8% might lead to gastrointestinal problems,(3) so avoid that approach. Instead, take advantage of the fact that PowerBar C2MAX makes it easy to get this dual source energy blend.
- Second, keep in mind that pushing the envelope on carbohydrate concentration only makes sense for endurance events of 2 hours or longer.
- The thinking is that the gut can be trained to handle more carbs and fluids during exercise. Take advantage of this by making small, incremental increases in carbohydrate concentration and then thoroughly testing your responses to those increases during training, including race-paced training sessions. Start this approach at least 4–6 weeks out from your target race, a few times per week.
- Hydration is still very important — it is not all about the amount of carbs! Remember that temperature and humidity affect your fluid and electrolyte needs. Adapt your fluid and sodium intake to training and race conditions — ideally in weather that will be similar to race day — so that you don't lose much more than 2% of your body weight due to fluid loss during exercise. Find out more on this topic and determine your own individual sweat rate using the PowerBar Sweat Rate Calculator.
- And finally, if you are doing fine with a 6–8% carbohydrate concentration, and you want to squeeze everything you've got out of your next big competition, an increased-concentration fueling plan can be considered — just make sure that you are using multiple transportable carbs, such as those in PowerBar products that feature PowerBar C2MAX!
| Examples of Increased-Carb-Concentration Fueling Plans |
| Example 1: Reid Coolsaet's fueling and hydration plan (Scotiabank Toronto Waterfront Marathon): |
| Km | Fueling/hydration | Available to consume | Planned to consume | Actually consumed |
| | | Carbs (g) | Fluid (ml) | Carbs (g) | Fluid (ml) | Carbs (g) | Fluid (ml) |
| 5 | PowerBar® Energy Gel (with PowerBar® C2MAX dual source energy blend) plus water | 27 | 250 | 19 | 190 | 15 | 140 |
| 11 | Ironman PERFORM™
sports drink mix* (with PowerBar C2MAX) | 25 | 250 | 18 | 190 | 15 | 150 |
| 15 | PowerBar Energy Gel (with PowerBar C2MAX) plus water | 27 | 250 | 19 | 190 | 19.5 | 180 |
| 21.2 | Ironman PERFORM
sports drink mix plus
90 mg caffeine | 25 | 250 | 18 | 190 | 15 | 150 |
| 24.5 | PowerBar Energy Gel (with PowerBar C2MAX) plus water and 90 mg caffeine | 27 | 250 | 19 | 190 | 13 | 120 |
| 30 | Ironman PERFORM
sports drink mix | 25 | 250 | 18 | 190 | Missed bottle; drank on-course sports drink: 3 | Missed bottle; drank on-course sports drink: 30 |
| 35 | PowerBar Energy Gel (with PowerBar C2MAX) plus water | 27 | 250 | 19 | 190 | 17 | 160 |
| 38 | Ironman PERFORM
sports drink mix (with PowerBar C2MAX) | 25 | 250 | 18 | 190 | 9 | 90 |
| | | | | | | 106.5 g | 1020 ml |
|
| Examples of Increased-Carb-Concentration Fueling Plans |
| Example 2: Dylan Wykes' fueling and hydration plan (California International Marathon): |
| Mile | Fueling/hydration | Actually consumed |
| | | Carbs (g) | Fluid (ml) |
| Start | PowerBar® Energy Gel plus water (with PowerBar® C2MAX
dual source energy blend) | 10 | 100 |
| 3.3 | Ironman PERFORM™
sports drink mix (with PowerBar C2MAX) | 19 | 190 |
| 5.5 | Ironman PERFORM
sports drink mix (with PowerBar C2MAX) | 19 | 190 |
| 8.5 | Ironman PERFORM
sports drink mix (with PowerBar C2MAX) | 19 | 190 |
| 13 | Ironman PERFORM
sports drink mix (with PowerBar C2MAX) | 19 | 190 |
| 16.5 | Ironman PERFORM
sports drink mix (with PowerBar C2MAX) | 19 | 190 |
| 19.4 | Ironman PERFORM
sports drink mix (with PowerBar C2MAX) | 19 | 190 |
| 20.4 | Ironman PERFORM
sports drink mix (with PowerBar C2MAX) | 19 | 190 |
| 22 | Ironman PERFORM
sports drink mix (with PowerBar C2MAX) | 19 | 190 |
| 23.5 | Ironman PERFORM
sports drink mix (with PowerBar C2MAX) | 19 | 190 |
| | | 171 g | 1710 ml |
|
* Ironman PERFORM™ sports drink mix was used for these athletes; it was mixed to be more concentrated (using less water) than the ready-to-drink Ironman PERFORM™ sports drink.
References:
1. Jeukendrup AE, Moseley L. Multiple Transportable Carbohydrates Enhance Gastric Emptying and Fluid Delivery. Scand J Med Sci Sports 2010; 20: 112–121.
2. Currell K, Jeukendrup A. Superior Endurance Performance with Ingestion of Multiple Transportable Carbohydrates. Med Sci Sports Exerc 2008; 40: 275–281.
3. Maughan RJ. Effects of CHO-Electrolyte Solution on Prolonged Exercise. In: Perspectives in Exercise Science and Sports Medicine. Lamb DR, Williams MH ed. Benchmark Press, Carmel. 1991. 35–89.
4. Jeukendrup AE. Carbohydrate Feeding During Exercise. European J Sports Sci 2008; 8: 77–86.
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