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Fat is Fuel: The Road to La Ruta, Part 5

For the last six months my dietary goal has been fairly simple: use more fat and less glycogen (stored carbs) for fuel during long rides. You’re probably wondering why I’d do that when I could just carbo-load the night before and suck down a few gels to get through the day.

Dirk Shaw

Editor’s Note: This is the fifth part of an eight-part original GP series, The Road to La Ruta, in which contributor Dirk Shaw chronicles his training for the Fool’s Gold 100 and La Ruta de Los Conquistadores — one of the toughest mountain bike races in the world. Check back throughout the summer to watch the story unfold.

For the last six months my dietary goal has been fairly simple: use more fat and less glycogen (stored carbs) for fuel during long rides. There is a direct correlation between using more fat to produce energy and increasing aerobic fitness. This is essential for the type of endurance racing I do.

Road to La Ruta is a series of dispatches, essays and features captures the intense journey of a cyclist as he trains for a mountain biking race across Costa Rica and what many consider one of the toughest in the world: La Ruta de Los Conquistadores. Read the series »

Using fat as fuel? You’re probably wondering why I’d do that when I could just carbo-load the night before and suck down a few gels to get through the day. A new school of thought is emerging, though, that debunks the myth that a diet rich in starchy carbohydrates is the best way to fuel during training and racing. Dr. Allen Lim, the guy behind Skratch Labs and former physiologist and nutritionist for the Garmin-Slipstream racing team, goes so far to say that there’s nothing nutritious about it.

Let’s look at the fuel the body uses. Most abundant is fat, which serves as the primary energy source for your muscles during low- to moderate-intensity exercise; then there are carbohydrates, which fuel moderately high- to high-intensity exercise. Fat is generally stored under the skin, and we can store a lot of it (obviously, in some cases). Carbohydrates are stored only in small amounts, as glycogen, in the muscles. This creates tension for endurance athletes. Your body has anywhere from 2,000 to 2,500 calories of carbohydrates available for use during an event. During an intense workout, my body burns anywhere from 900 to 1,000 calories per hour. That means I can rely on carbs for a couple hours of intense riding, but once I burn though the stored calories, I will hit a wall.



Call me Luddite. Or just cheap curmudgeon. You can keep your fancy, schmancy gels (snot), your sticky energy gummies (boogers) — I eat food when I ride. Bananas are a staple, of course, but so are nuts, dried fruits, and my favorite quick energy food, boiled potatoes. They’re cheap, they’re easy, and they convert to blood glycogen faster than your laboratory concoctions. Boil up some baby reds or some Yukon Golds, pop them in a small plastic baggy and you are good to go. Another plus — I know what I’m ingesting. It’s called “food”. Any idea what’s in your gel block? I didn’t think so.
Scott Packard

My favorite snacks usually revolve around comfort food, especially on long rides. The best for me are Honey Stinger waffles (especially the lemon and strawberry) because they remind me of the pastries we used to buy growing up while riding bikes along the canals of Amsterdam. They may not taste exactly like a good Dutch stroopwafel, but they’ve gotten me through a couple Ironmans and more road and mountain races than I can remember.
Austin Parker

I’m a sucker for sausage, but don’t ever quote me on that. If I’m just out for a recreational cruise with friends I take a few landjäger, German-style dry-cured beef and pork sausage. It’s like a better Slim Jim. Otherwise, I rely pretty heavily on a revolving door of supplements, which right now includes whatever bars or gels I have on hand — a custom blend from INFINIT and Osmo Active Hydration.
Jeremy Berger

Conventional wisdom might tell you to just keep loading up on carbs to avoid bonking. But this approach has consequences. Your body cannot digest carbs fast enough to keep up with what you’re burning, and on a long endurance ride you can easily feel bloated and nauseous just from what’s being stuffed down your throat. The ideal is balance: a combination of fat and carbs that fuels you for the long haul and provides energy when you need it. A better balance also allows carbohydrate-based calories to be used over longer periods of time.

The challenge from a planning perspective is that most people have no clue about the rate they burn carbs or fat. Until I had my F.U.E.L. testing done, I had no idea. It turns out I’m a huge carb burner. Tests showed that of 1,000 calories burned in an hour, about 650 came from stored carbs, and only 350 from fat. A better balance would be more like 50/50. This insight helped me understand why I felt miserable on long rides in the past, and it proved the catalyst for making different decisions about what I eat.

Early this season I rode into a deficit on purpose. Not smart. I grew delusional, light-headed and considered poaching a banana from a food stand. But I wanted to see how long I could go in my “tempo” and “sub-threshold” zones before I totally depleted my stored carbohydrates. This was far from my best day on the bike. I set out for what would be a 3.5-hour ride, which consisted of me leaving my house on the mountain bike and pedaling about 12 miles to a local trail. On the way home, I was grinding back up a paved hill that is aptly titled “Johnson Ferry Grunt” on Strava when I started to feel the symptoms. Within minutes, I had totally bonked. After about 15 minutes of delusion, I felt my body begin to regulate. It was as if it stopped seeking carbohydrates and decided to use fat for energy. The fog cleared, and I found a second wind for the last 40 minutes home.

Fast-forward four months. I have obviously added significant volume in my training but have also eliminated many foods with processed wheat, which has actually been quite easy given that my daughter has Celiac disease and we often eat gluten-free as a family. In addition to removing wheat, each meal or snack includes small portions of good fats like almonds, avocado, olive oil and even dark chocolate.


I’ve also radically altered what I eat on the bike. The jersey used to be stuffed with several packets of GU, a sports bar and a milky sports drink. After five to six hours of racing on this kind of food, I would get a serious stomach ache and my body would stop accepting food; my body simply couldn’t process carbohydrates fast enough to convert them to fuel. Now, I prefer to bring gluten-free whole grain oat bars, bags of dried fruits with almonds, and Justin’s almond butter. For fluids, I switched from high-calorie drinks to lighter options with lower calories.

This weekend is the Fool’s Gold 100, a serious test of how well I have been able to balance carbohydrates and fat in my new diet. Stay tuned for a race report.

Dirk Shaw is the Group Director at WPP / Ogilvy & Mather. His pursuit of two-wheeled adventure includes training for long distance mountain bike races, commuting to work and ripping through canyons on his Daytona. Follow Dirk’s musings about cycling on Tumblr or his blog for insights and observations on media. @dirkmshaw.

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