Sunday, October 01, 2006

Low-Carb Marathon Runners Burn Fat For Fuel

Marathon runners like these don't need to load up on carbs for energy

There are some things in life that you just don't think about much when you are overweight or obese. One of those things is running in a marathon. Actually, scratch that, you're not even thinking of running ANYWHERE, much less a marathon! :D

But when you start livin' la vida low-carb and radically change your weight and health for the better, it makes you WANT to consider things like running in a marathon to help keep you focused on the task at hand to accomplish things you never thought would be possible.

That's exactly what my friend Kent Altena, who has lost over 200 pounds on the Atkins diet, is going to be doing in two weeks. This former 400+ pound man is embarking on an adventure like none other when he competes in a half-marathon in just a matter of days. Now that the weight is off of his body, he is ready to show the world the new Kent (is that Superman underneath that suit? LOL!) and very likely become the only former 400-pounder to run and finish that race. BEST WISHES TO YOU, KENT!

When you talk about training for an event such as a marathon, inevitably the dietary routine involves loading up on carbohydrates such as pasta and rice to be used as energy during the extended workout. But as Kent explains in his latest how to do Atkins video, that's just not necessary for people who are livin' la vida low-carb.


It's interesting Kent made this video because I just got through reading a book called "4 Months To A 4-Hour Marathon" by a man named David Kuehls. This 100-page, easy-to-read book is full of lots of practical advice about how to train and make it through a marathon experience.

You can check out this revised version of the book at

Unfortunately, as excellent as the book is for people genuinely interested in marathon running, Chapter 4 should be completely ignored by anyone who is livin' la vida low-carb. It's called "Carbo-nated" and Kuehls contends that "the only fuel that works (for marathon running) is: carbohydrates, including breads, pastas, beans, pancakes, sugars, etc. He added to "keep the carbohydrate tanks filled" to keep your endurance up during your training.

In a sidebar section called "Fad Diets," he warns of cutting carbs and loading up on protein and fluids.

"A word about fad diets while you are training for your 4-hour marathon: DON'T. You want to keep your energy levels as high as possible--otherwise you'll slow recovery and feel too worn out to train--and the way you do that is by eating a healthy, balanced runner's diet."

Oh sure, all those carbs are real healthy for your body! Why not burn fat for fuel instead, Mr. Kuehls?! That's what Kent is doing during his training for his half-marathon and he is not alone. He fully expects to beat two hours when he races and it will all be while on a low-carb, high-fat diet.

In his video, Kent notes three articles about this subject:

Dr. Stephen D. Phinney
Dr. Jonny Bowden
Dr. Mary Vernon

Kent also makes mention of the research Dr. Jeff Volek (who I interviewed earlier this week) did on low-carb diets and physical endurance performance. The scientific evidence is there to make the case for low-carb as the preferred diet for training to run a marathon. Getting rid of this notion that you HAVE to eat carbs when you exercise goes against all you've ever heard about runners.

Remember when I blogged about this low-carb marathon runner who lost over 100 pounds and is passionate about challenging the carb-loading myth as well.

With all that said, Kent summarizes the research as follows:

1. Let your body get used to low-carb and burning fat for fuel for up to two weeks before attempting to continue your regular athletic performance. Then your body will be ready to train at the next level.

2. Be sure to consume enough potassium and sodium to replenish the cardiovascular reserve and preserve lean body mass.

3. Eat plenty of dietary fat and between 1.2-1.7g/kg of your body weight in protein. Fat is your fuel...EAT IT!

This is such an important subject and I'm glad Kent discussed it in his latest video. Do you have any experience with marathon-running while on a low-carb diet? Please share that with us.

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Blogger Newbirth said...

I tried to run a 12k on low-carb. No go. I barely managed to eek in under 2 hours. I had NO energy. This past year with plenty of carbs, I ran the same course in 1:30 and had tons of energy. I always carb up before that race now, starting the day before.

10/01/2006 11:21 PM  
Blogger low carb tennis guy said...

I run 6.5 miles daily on a treadmill, which is just over a 10K distance, at a speed of 6.5 mph, and have more than enough energy to get through it on a low carb diet. In fact, a lot of times I go and play 2-3 hours of tennis afterwards, still with plenty of energy. No need to "carb up". Maybe there were other factors at work causing you to have no energy on the day of that 12K, Newbirth. Just a thought.

10/04/2006 5:43 PM  
Blogger Cherish said...

Hi Jimmy,

I recently found your blog and LOVE it! I follow the Carb Addicts diet, but a lot of the info crosses over.

I'm interested in learning more about low-carb diets for endurance exercise. This past summer, I got interested in triathlon. I'm only doing shorter events now, but I'm worried about how to train for longer distance events. Unfortunately, I can find nothing that talks about how to handle electrolyte replacement or nutrition during an endurance event. If you find out anything on this topic, I'd love to hear it. And thanks for passing on all the info!

10/29/2006 7:30 PM  
Blogger Bowulf said...

Cherish, how long is your endurance race? Is it shorter or longer than 1-2 hours? If it's longer than 2 hours, there is two things you could do. Bring some of the low cal endurance sport drinks along to drink (some races allow you to pre-position your personal drinks along the route), or there are low carb electrolyte tablets as well. For myself, as long as I kept myself hydrated I was fine. The whole Gatorade culture is somewhat overrated as most people are looking for the sugar rush rather than depleted electrolytes.

10/31/2006 6:18 AM  
Blogger Brad said...

I am serious runner and would 100% agree with what you said. In the absense of carbs, your body will burn fat for fuel.

The only hitch is that our bodies can burn carbs far more easily than they can fat. When you are running longer distances, you can feel your body running out of glycogen and beginning to turn towards fat. You can also feel it becomes noticably harder to run and your pace slows.

This brings me to my point. It all depends what your goals are. If you are running to lose weight, maybe low carbs make sense. If you are running to go fast, I think you may want to eat that second roll.

1/10/2010 5:43 PM  
Anonymous Anonymous said...

Brad, your comment was respectful but in my view, misinformed. I have spent a lot of time in a ketogenic state. I run out of glycogen on day 3. Then my body is forced to become efficient at burning fat because it's not getting any carbs.

Once I am keto-adapted (so to speak) I do not run out of energy for long-burn types of activities.

I know the research so far shows a disadvantage in terms of burst-power output (for sprinters, etc.) But I have seen nothing so far that would discourage me from running a marathon keto-adapted.

When you say that the body burns carbs more easily than fat, I think what you really mean is that the body burns carbs more easily than fat when it has been adapted to do so.

7/22/2013 12:14 AM  

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