Monday, November 3, 2014

Keep it Simple to Perform your Best: Using Sugar As Fuel.

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Here is a copy of the most recent article:

Keep it Simple to Perform your Best: Using Sugar As Fuel. 
by Shannon McGinn, RRCA Certified Distance Coach
October 2014

Recently I have noticed a lot of talk in the endurance world about the best way to fuel for the long haul. Runners are turning to low-carbohydrate diets and reporting excellent results. Most of these reports come from those following a Paleo diet plan. Simple sugars are being categorized as “bad” and if carbohydrates are used at all, more complex carbohydrates are being touted as the best way to fuel. 

There is some support from professionals who conclude that once a person has become fat-adapted, meaning they have trained their bodies to burn fat instead of glucose for energy, they will then be able to perform better in ultra-endurance events, such as those lasting over 5 hours. However, this goes against the long standing position that carbohydrates are required to fuel the body.  We need to remember that correlation does not imply causation. For example, in most cases a low-carb diet leads to significant weight loss and we know that simply dropping weight will automatically result in faster running. Therefore, I am not yet convinced that  low-carb is the way to go for sustainable training and optimal race day performances. 

Despite the newest theories about the body not needing carbohydrates for fuel, the American College of Sports Medicine continues to take the position that carbohydrates are required to maintain blood glucose levels during exercise and replace muscle glycogen. In my experience, simple carbohydrates fuel me best, even when my events last over 5 hours. I find the strain and distress on the body required to become fat-adapted to be extremely unpleasant and potentially unhealthy. If you want to keep things simple, you may find simple carbohydrates to be your best source of fuel as well. 

There are two main types of carbohydrates, complex and simple carbohydrates. Both types are made from sugar. Complex Carbohydrates are starch and fiber and made up of many molecules of sugar connected in chains. These chains must be broken down into single molecules of sugar to be used as energy. Simple Carbohydrates, often called simple sugars, are made of up of one or two molecules of sugar. As a result, it takes very little effort to use simple sugar as energy  Based upon my experience running close to 300 races and over 110 miles in one day, I have learned that simple carbohydrates are my ideal source of fuel when training my hardest, racing my fastest, or trying to endure. 

Keep in mind that there is a difference between what we should eat in daily life versus what we should be consuming as “fuel” during an endurance event.  In daily life, is it not a good idea to consume large amounts of simple sugar. Because very few nutrients come along with most simple sugars, our consumption of simple sugars should be limited. Simple sugars are often significantly abused, being consumed in unhealthy amounts when not needed. When too much sugar is consumed, what is not used is stored as fat.  Abuse of simple sugars often leads to serious health issues.

But during exercise, while the body is working hard, simple sugars have been proven to be an incredibly fast digesting fuel source, especially when compared to complex carbohydrates, protein, and fat. During a race, I seek out fast digesting sugar from densely caloric sources in the form of things I would never consume in day-to-day life. During a race, I consume simple sugars in small amounts along the way because they are so powerful. For example, in addition to what I take before a race, I will take one gel every 9-12 miles along with about 2-3 ounces of sports drink or soda per aid station, if available. Overloading my system with too much sugar can cause stomach upset and negative results. I consume what I can to burn, thus eliminating the concern that eating sugars during a race will result in longstanding health issues. 

How much sugar is enough? It is often recommended that endurance athletes attempt to consume 60-90 grams per hour (i.e. 240-360 calories per hour) to perform their best. I find this amount to be quite high and difficult for many to achieve. In my work with athletes, I find that newer runners tend to not consume any or nearly enough calories while training. Although we can get away with less fuel during our slower training runs, and in some cases depletion train on purpose, we should also practice how to fuel properly for a high intensity race. 

To practice proper race-day fueling, first do not plan to consume a large amount of sugar all at once. Instead plan to spread out your sugar consumption over the duration of your run. Consider initially increasing your consumption of carbohydrates to 100 calories per hour by simply taking one gel per hour. Over time, try to add more sources of carbohydrates, such as one gel per half hour or alternate with sports drink, to help get your carbohydrate intake as close to the recommended amount as you can tolerate. Keep in mind that your pre-run fuel also counts towards this total, so take a gel or two right before you start.  

You do not need to use only gel. Any simply sugar can work if you are able to consume it on the run. To identify what products contain simple sugar, when reading an ingredient list look for fructose, glucose, monosaccharides, lactose, maltose, and sucrose. Simple sugars may also be listed as raw sugar, brown sugar, beet sugar, cane sugar, confectioner’s (powdered) sugar, molasses, maple syrup, sugar cane syrup, cane juice, invert sugar, malt syrup, and high fructose corn syrup. Simple sugars are naturally found in fruits, milk, and other dairy products.  

I spent years trying alternative, natural, and/or “healthier” fuel sources. I have found that complex carbohydrates take too long to digest or upset my stomach. Too much fructose alone is known to cause stomach upset and did so for me. But fructose along with other sugars is a great combination. Honey is a special case and has very positive results if you can find a way to carry it. 

Ultimately, those gel packets that I disliked at first have become my first choice in fueling for races of 90 minutes through a marathon. The are lightweight, densely packed with calories, easy to carry, and fast to digest. Gels along with race supplied sports drink gives me just what I need to stay well-fueled. 

In ultras, I find that I cannot always tolerate gels for the longer time on my feet.  Therefore, some other sources of fast sugar that I turn to during an ultra will include Coca Cola and Mountain Dew. If fruit is available, I always take it. As a rule, I never turn down the soda and I never turn down fruit, especially if it is any type of melon or orange slices. My best races have always been fueled on a combination of fruit (fructose) + sugar (glucose). 

When running a very very long time, highly sweet fuel sources eventually become intolerable. When this happens, I will turn to more complex carb sources that fall on the salty side of the palate. When racing for more than 10 hours, my body also needs some of the other macronutrients (fat and protein) it would normally receive during daily life. Solids foods will take longer to digest, but when races last a very long time and the pace is slower, small amounts of solid food will help settle my stomach and will ultimately become useful energy sources as well.  

To learn more about the role of simple carbohydrates as a source of fuel, here is an article about sugar for endurance athletes.

The take away:  
(1) A mixture of Fructose and Glucose is ideal for many runners.  
  1. Do not overload yourself with sugar in large doses. Spread out your fuel consumption out along the way.
  2. Aim to consume up to 60-90g of carbohydrate/hour. Start with an amount you can tolerate and work on consuming more per hour during your training cycle.

It is my opinion that fueling does not need to be very complicated. I try to fuel in a way that does not force my body to work any harder than it has to. Simple sugars are fast and easy to break down. If taken in small amounts along the way, with an effort to meet the recommended 60-90 grams per hour, I find that I am using what I consume and this makes simple sugar my ideal source of fuel. 
Shannon McGinn is an RRCA Certified Distance Running Coach and the owner of Creating Momentum, LLC.  She is a life-long runner, becoming more involved in racing after surviving cancer.  She considers herself a marathon and ultramarathon specialist, earning several USATF National Championship top 10 or better placements in the 50k and 50M distances. She has not missed a day of running since December 2011.