In everyday life, eating is easy–too easy. We overeat. We eat mindlessly. We eat poorly, yet we still muddle through our day reasonably well.
But if you’re interested in doing an endurance event–like a marathon, a 50-miler, an Iron Man or riding a century–muddling through isn’t going to work so well. Turns out something as simple as getting enough calories becomes a lot harder when you’re pushing your body for longer than a couple of hours.
As a Registered Dietitian with a Masters degree in Nutrition from Bastyr University, trainer Jess Mullen has thought about this more than most. As an ultrarunner, recently returned from a successful 135-mile race at Badwater, she’s learned how to put it into practice.
The first thing to know, she says, is that nutrition is part of a good training plan. And like the rest of your training, you need to start thinking about this long before race day.
Start with some basic math, she says.
About how many calories will you expend? Depending on your size and other factors, figure on burning upwards of 500 calories an hour.
Then think about how much you’re taking in. A gel? That’s about 100 calories. A sports drink? That’s about 200.
Now subtract. After a few hours, you’re bound to be well into the negative. The longer the event, the bigger the deficit.
While you may be tempted to see this as an opportunity to shed some excess pounds, this is not the time to diet, Jess says. When you’re pushing your body, you’ve got to keep eating and drinking or you could wind up not finishing your race—or worse, in the hospital with dehydration.
Not to say it’s easy. While you may burn 500 calories an hour, you can’t eat that much. Your body just won’t digest it when you’re in endurance mode.
Jess suggests having a goal. For most people, that means taking in 150-300 calories per hour.
“And eat frequently,” she says. “It’s easier on the body to have 100 calories two times an hour rather than 200 calories all at once. “
To some people, the very thought of eating while running is nauseating. Eat anyway, Jess says.
“In really long events if you can’t eat when you’re nauseous, you’re not going to finish the race,” she says.
In fact, feeling nauseated can actually be a sign you’re low on calories or salt.
“Most people underestimate how much they can tolerate and it’s like a death walk at the end,” she says. “That’s what they call hitting the wall.”
So what do you eat? Jess is ordinarily a big proponent of Paleo eating. But not on race day.
“When I perform athletically, I like to be a competitive as possible,” she says. A Paleo diet isn’t going to provide the type of calories–the carbs–you need during endurance events. Not only that, all that protein is tough to digest.
In normal life, her sugar comes from fruit. Not when she’s running an ultrarace.
“You have to be careful because it can cause stomach upset,” she says.
Instead, Jess turns to things like Rice Krispee Treats or potatoes. Even candy, like Gummi’s. And gels like Gu or Clif Shots have become a staple. They’re quick, portable, and easy to digest.
In events that will last more than four hours or so, she says you need to supplement that sugar with small amounts of fat and protein, too.
The most important thing to do is experiment beforehand, during training. See what you can stomach, and how much.
“What you’re trying to find is what range works for you, where you can maximize the calories you can take in,” she says.
You’ve also got to think about your fluid intake during long events. Shoot for 15 ounces an hour, she says, more if it’s hot. And while plain water is good, you’re also going to need to replenish the salt and electrolytes that you’re losing to sweat. Try V-8. Broth. Sports drinks. Even salt tablets. See how you feel. See how much you’re peeing. See whether you still have energy towards the finish line.
And when you’re done with the race, she says, the best thing you can do is return to a healthy diet. A Paleo diet.