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2071 Views 0 Replies Latest reply: Nov 30, 2012 3:34 AM by pacificfit
pacificfit Legend 147 posts since
Jan 9, 2008
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Nov 30, 2012 3:34 AM

A Low Carb Endurance Primer: What To Say When Your Friends Tell You That You Need To Eat Carbohydrates For Proper Endurance Fueling

Let’s say you decide you want to join the growing list ofindividuals who have decided to limit intake of starches, bread, pasta, sugars,gels, sports drinks, bars and other traditional endurance foods.


Once your training partners, family or other friends learnthat you’re eating fewer carbohydrates, you’re probably going to hear severalobjections, along with some scoffing and raised eyebrows.


And usually, the criticism of a low carbohydrate diet for triathletesfalls into three categories of objections or questions. Here is what people aregoing to say, and what you need to know to respond properly.


Objection #1: Isn’t glucose and carbohydrate necessary for energyduring exercise? You’re going to bonk if you don’t eat carbohydrates.


While it is true that your body’s cells can certainly burnglucose from carbohydrate for energy, fat is actually a preferred energy sourcein nearly every cell of your body, and especially for your mitochondria, whichare the energy-creating compounds within most cells. Until extremely highexercise intensities are achieved (which is rarely the case among enduranceathletes) or until the body has exhausted all storage carbohydrate byexercising for 2-3 hours continuously, fat is completely useable as an energysource – and even after that point, it only takes relatively small amounts ofcarbohydrate to continue to tap into the body’s own storage fat. Specifically,natural saturated fats, omega-3 fatty acids, and medium chain triglycerides areextremely dense energy sources that produce very little damaging byproductsfrom their metabolic use for energy – compared to burning blood glucose forfuel, which can cause a significant amount of free radical damage.


But some specific parts of the body do need glucose on daily basis – such as the brain, the nerves,special proteins called “glycoproteins” (which form important compounds such asmucus), and cells within your immune system, your gastrointestinal tract andthe kidneys. However - the maximum dailyamount of glucose calories required by these parts of the body is about 500-700carbohydrate calories, and not the 1500-2500 carbohydrate calories consumed bymost endurance athletes!


Objection #2: Isn’t all that fat you’ll be eating as a substitute forcarbohydrate dangerous because of high cholesterol, heart disease, and weightgain?


Not only can a highfat, low carbohydrate diet perform better for weight loss compared to a lowfat, high carbohydrate diet, but there is no evidence that a high fatderived from healthy, natural fat sources increases risk of heart disease – unless fat consumption is paired with highamounts of fructose and a moderate to high intake of starchy, sugarycarbohydrate sources. It is at the point when high fat consumption iscombined with high carbohydrate consumption that cholesterol in the bloodstreamcan become oxidized and lead to risk of heart disease.


As a matter of fact, the whole idea that high cholesterolcauses heart disease is a flawed hypothesis, and entire books have been writtenon it. A very good place to start your journey into learning about the positiveand healthy properties of fats would be the website


Objection #3: Don’t you need to load with carbohydrate before a race? If you don’t carbo load you’re going to bonk.


Once you begin eating a low carbohydrate diet without cheating and including high carbreload days or meals, your body can, within 2 weeks, become extremely efficientat burning fat – a stark difference from the type of fuel utilization that occursin the endurance athlete trained to eat a gel every 20 minutes during everysingle training session, or to constantly have sports drink on the edge of thepool and a bowl of pasta waiting at home to re-fuel after the workout.


This means that once you become “fat adapted” you will needrelatively fewer carbohydrates during race week or the day before a race, sinceyour body develops an enhanced ability to conserve storage carbohydrate(glycogen) and also an increased ability to utilize fat as a fuel, both duringrest and on race day.


What this also means is that an entire week of traditional carbohydrateloading and high sugar intake will not be necessary before your race, and ifyour goal is weight loss, health, or longevity, may actually end up doing moreharm than good if you repeat this “carb loading” scenario multiple timesthrough a training year.


Since I have personally shifted to a lower carbohydrateintake, I have found that the 85-90% carbohydrate diet I was eating during thoselast few days leading up to a race is no longer necessary. The only increase incarbohydrate that is necessary during race week is A) a carbohydrate densebreakfast the day before and the morning of the race; and B) avoiding anyfasted, carbohydrate depleting sessions in the last few days leading up to therace. Because of the natural reduction in physical activity during a taper,simply maintaining your normal carbohydrate intake would still be considered“carbohydrate loading”, but not in the common tradition of loading, whichtypically includes 7-10 days of high carbohydrate intake before an event.


For more helpful resources on a healthy race day nutritionplan that falls into the category of “low carbohydrate fueling”, check out this article I wrote after winning Leadman 125 earlier this year. For an actualmeal plan and more specifics on low carb fueling for endurance, you may alsowant to check out my LowCarbohydrate Guide For Triathletes.

My blog is at

Also, I'm giving away a free 7-part series on "How To Become Superhuman" at

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