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Fueling Facts

Posted by: on May, 19 2016

Found on RunnersWorld.com and written by Erin Strout

Maintain your peak condition with a balanced diet.

Serious runners do what the training schedule says, hoping to get faster. They replace their shoes every 500 miles, hoping to avoid injury. They methodically hit refresh on the weather forecast days before the race, hoping the humidity drops. For a sport that attracts its share of control freaks, there are remarkably few things that runners—despite their best efforts—control about their results.

In fact, aside from getting adequate sleep, there is exactly one thing runners can control that is proven to legally enhance performance: what they choose to put in their mouths.diet fueling
Proper nutrition and hydration are critical components to better running. Yet many athletes are still either playing by an antiquated handbook—one that prescribes giant plates of pasta and bottles full of neon-colored sports drinks—or following the latest fads, like eliminating gluten or chugging cherry juice after a workout. And while many of these strategies in various forms may have their place in the runner’s diet, there’s a lot more to consider than carbs, electrolytes and superfoods when it comes to fueling the successful endurance athlete.

“Runners stereotypically don’t pay attention to the quality and nutrient density of the food they eat—they’re lean, they aren’t fat, so they think they can eat whatever they want,” says Jay Sutliffe, associate clinical professor in the Northern Arizona University department of health sciences, who is also a nutrition counselor for the university’s cross country and track teams. “And the older runners are the worst.”

It doesn’t have to be complicated. When it comes down to it, the country’s highest-performing distance runners don’t fall for fueling fads or overthink what they’re putting in their bottles or on their plates. They keep their diets basic—whole, quality foods that include grains, fruits, vegetables and lean protein. It’s all those micronutrients (vitamins and minerals that the body needs small amounts of, like magnesium, sodium, vitamin C and others) that help you recover from hard efforts and replenish your stores, allowing your body to adapt to the stress and ultimately perform better.

“My overall diet focuses on nutrient-dense and minimally processed foods,” says Shalane Flanagan, Olympic bronze medalist and 2:21 marathoner. “I do not eliminate anything in my diet; I just try to minimize my sugar and alcohol intake when I’m trying to get to racing leanness.”

With the help of research and nutrition experts, we’ve narrowed things down to five basic facts that will help runners perform better.


While researchers are trying to figure out if endurance athletes can teach their bodies to oxidize more fat as fuel, the truth is that carbohydrates, stored as glycogen, are the best and most readily available form of energy for muscle strength and endurance—and runners need carbohydrates to perform and recover.

How much of the diet to devote to carbohydrates depends on the athlete and where she is in the training cycle. For somebody who is in a low- or moderate-volume period, dietitians prescribe 3 grams per kilogram of body weight. As training volume increases, try to get in 5 or 6 grams of carbohydrate per kilogram of body weight per day.

The trick is to choose the forms of carbohydrate well. Carbs got a bad name over the years because most people associated them with white breads, pasta and refined grains—many of which also contained refined sugars and saturated fat. But fruits and vegetables, as well as whole grains, also count as carbs, and those are the kind that athletes should gravitate toward.

“You can pick a piece of fruit or you can pick a box of crackers,” says Stephanie Howe, an elite ultrarunner who is working on her doctorate in nutrition and sport science. “The carbs may look the same, but the apple is also going to give you essential vitamins and minerals.”

As for pre-race carb-loading, it really only helps for those who are running marathons or ultra-distances, and it doesn’t mean an athlete should inhale a giant plate of pasta 12 hours before the gun goes off. Instead, nutritionists advise increasing intake beginning three or four days before the race by adding a few more carbohydrates to each meal.

“Most people already have enough glycogen storage for 20 miles of running,” says Alicia Shay, a nutrition counselor at Hypo2 High Performance Sport Center and an elite trail runner in Flagstaff, Arizona. “If you eat a whole bunch of pasta the night before the race, it can lead to gastric distress, and it’s not going to be readily available. Just add small amounts of carbs throughout the day so you can digest it.”

When it’s race time, switch to a different kind of carb, to stave off the dreaded “bonk.” Trent Stellingwerff, innovation and research physiology lead at the Canadian Sport Institute, says to feed the body simply digested carbohydrates—such as gels, chews and sports drinks that contain calories—during racing or intense, prolonged exercise. “Simple sugars like sucrose plus fructose are the way to go,” he says.

But what about the increasing popularity of depletion runs during training (see Performance Page, page 18)? The scientific jury is still out, but many experts don’t recommend them unless they’re a last resort in the training arsenal—nearly all runners could see performance improvement by adding other simple stresses for the body to adapt to, like increasing mileage, instead of toying with fuel depletion.

But for those athletes who decide to give depletion a try anyway, Kyle Pfaffenbach, nutrition consultant for the professional Brooks Beasts team, who has a doctorate in nutrition from Colorado State University, emphasizes, along with other experts, that there is a safe time to do them in the training cycle—and it is early. Depletion runs take a toll that athletes can’t recover from fast enough during high-intensity periods or close to race time.

Bottom Line: Runners need carbohydrates, but should be careful in choosing the healthiest versions and not overdoing the intake. Science does not yet support the notion that most athletes will benefit from depletion runs, but those who try them should pick a safe time in the training cycle to allow proper recovery.


Coaches and sports nutritionists have been harping on it for years, but have you ever wondered if the 30- to 90-minute eating window to maximize recovery is for real? It is if you want your body to quickly absorb and use nutrients to repair muscles and replenish your stores. Nutritionists are still pushing a 3-4:1 grams carb-to-protein ratio when possible but say that it’s really only needed after prolonged or intense efforts. (Don’t go chowing down after an easy run.)

Howe is currently conducting research for her dissertation on recovery nutrition. What she’s finding is that the ratio, consumed in about 250 calories, will help replenish what an athlete has lost, but it may not be as important as merely eating something. And while many recovery food fads come and go, like chocolate milk and cherry juice, nobody has found a mystical source of recovery fuel.

“Usually your appetite is suppressed after a race or a workout, so I say that anything you can get down is good, whether it’s sport drink, a bar, a peanut butter and jelly sandwich,” she says. “There’s no magic superfood out there—there are a variety of foods that will get you the nutrients you need.”

Pfaffenbach encourages the Brooks Beast team to try to get post-workout fuel from liquid sources, so that it is quickly absorbed into their systems. He also downplays the chocolate milk hype, pointing out that it contains fat that will slow the absorption process. (Many also recognize that the original study on the effect of chocolate milk on endurance-athlete recovery was partially funded by the dairy industry.)

“There [is] no lack of products out there that have everything you need in a recovery drink,” Pfaffenbach says. “I recommend that the athletes check the ingredient lists for additives—or just make their own with organic options, like smoothies with fruits high in simple sugars; carbs; and add some whey protein.”

Pfaffenbach says to measure out a smoothie that has 8–10 grams of whey protein and 32–40 grams of carbohydrate.

Bottom Line: After long and/or hard training and racing efforts, jump-start the recovery process by eating or drinking 200-300 calories of 3-4:1 grams of carb to protein, up to 90 minutes post-exercise. Choose whole foods when possible, or check product labels for unwanted additives.


Although sports nutrition experts don’t agree on everything, one piece of diet advice they prescribe time and again: Eat more fruits and vegetables, every single day.

“We spend a lot of time talking about ratios—runners have basic needs for calories and fluids, but how you get those calories makes a huge difference,” Sutliffe says. “Typically, we see a lack of micronutrients in the diet that provide the vitamins, minerals, antioxidants and coenzymes to help build the mitochondria.”

We need to feed those mitochondria because they are the little cellular powerhouses that generate energy to the muscles, nerves and heart—and a box of cereal likely won’t do the trick. Where do those micronutrients come from? The perimeter of the grocery store, where you’ll find foods like kale, collards and spinach, which are the most nutrient-dense foods and are full of what endurance athletes need: Vitamins K, A and C, magnesium (helps reduce muscle cramps) and flavonoid antioxidants (anti-inflammatory).

Unfortunately, instead of filling shopping carts with produce, according to the U.S. Department of Agriculture, Americans are spending more time in the middle aisles, where they are getting 62 percent of daily calories from processed food containing high levels of refined sugar, refined grains, saturated fat and sodium. And, sadly, sports nutritionists don’t believe that a lot of serious runners are doing much better than the average.

“[The best-performing runners’] diets include fresh, unprocessed food, quality protein, and lots of fruits and veggies,” Sutliffe says. “It’s so simple and so overlooked by many runners—I am a big believer that the food you’re eating for every meal and snack is critical to adapting to the training stress.”

Shay subscribes to food author Michael Pollan’s mantra: “Eat food. Mostly plants. Not too much.” Athletes at the highest levels have well-balanced diets that aren’t extreme one way or the other, she says.

Bottom Line: Fuel performance by focusing meals and snacks on whole, quality foods, including lean protein (fish, eggs, poultry), whole grains (brown rice, barley, bulgur, quinoa, whole oats), legumes (beans, lentils), fruits, vegetables and healthy fats (nuts, avocados, seeds, fish).

The sports drink industry has done a great job of convincing athletes (and non-athletes) that they need electrolytes to perform better. We do—but probably not as much as we think. “There’s a lot of marketing going into the importance of electrolytes, and it’s sometimes overstated,” Pfaffenbach says.

The biggest concern about the loss of electrolytes—sodium, potassium, magnesium and calcium–comes when an athlete is training or racing for two to three hours or more. When running that long and losing electrolytes through sweat, there is a need to replace them with gels or sports drinks. Nutritionists recommend 0.5 to 0.7 grams of sodium per liter of fluids.

Athletes don’t have to go overboard, however. Shay helped a runner who had done a 100-mile race and couldn’t understand why he had gained 10 pounds. As it turned out, he was taking salt tablets and using electrolyte drinks throughout the race—more sodium than his system could process, even at an ultradistance.

“When your levels are off balance, you create a difficult environment for your muscles to function [in] properly—too much sodium, you’ll get bloated,” she says. “It’s almost the same as your thirst mechanism. Your body tells you when it’s thirsty. If you’re craving salt, you need it—but don’t take it blindly. Realize that most gels have a little bit of electrolyte in them, and it’s probably enough to get you through a marathon.”

As for hydration—well, the advice is still pretty basic. Stellingwerff suggests conducting the old sweat test to figure out how much fluid you’re losing. One liter of sweat equals 1 kilogram of body-weight loss. If you don’t drink anything, exercise for one hour and lose 1 kilogram, your sweat rate is 1 liter per hour. How much should you drink during a race? Drink when you feel you need to.

Bottom Line: Electrolyte replacement is most important for long efforts and/or particularly warm weather. Don’t take in electrolytes blindly, however—figure out how much you’re ingesting through gels and drinks, and don’t overdo it.


Take an afternoon to read a variety of runners’ blogs out there and you’ll find that the “secret” to success is obviously eliminating wheat, barley, rye, grains, legumes, dairy, salt, oils . . . the list goes on. More commonly known are names like “gluten-free” and “Paleo” diets; their advocates say that ridding themselves of one food group or another has propelled them to running greatness.

“It’s a huge pet peeve of mine,” Shay says. “People read this stuff, replicate it and think it’s somehow scientifically proven to help them run better. But it’s not rooted in evidence.”

With the exception of celiac disease and diagnosed food allergies, there’s little science backing claims that cutting gluten or following a diet that prescribes an overabundance of fat and protein will help performance—in fact, because science has proven that endurance athletes need carbs, as stated earlier, overdoing fat and protein just may hinder it.

What these diets may force a runner to do, however, is cut down on foods like cookies and crackers, Howe says.

“For those who don’t have celiac disease or allergies and still claim to feel better after eliminating gluten, it’s probably because they’re eating better, whole, unprocessed food,” she says.

But if an athlete is devoted to a certain diet—Paleo or gluten-free, for example—Pfaffenbach believes there’s a way to be reasonable about it.

“There’s a healthy approach for whatever belief an athlete has concerning diet, unless somebody is hell-bent on eating McDonald’s every day,” he says. “And sometimes if an athlete believes that eating or not eating something will make them run faster, then it’s okay to find a way to work around it.”

Bottom Line: Science doesn’t support the claim that eliminating food groups can boost running performance, unless an athlete has diagnosed allergies.


How do Olympians fuel their fire? It comes down to the basics of good, balanced nutrition—and the elimination of processed foods.

Olympic marathon bronze medalist

Overall Diet: “When people ask me what they should do, I tell them to eat more vegetables. I focus on quality—all organic.”
Prerace Dinner: Pesto pasta with salmon.
Race Fuel: Cytomax pomegranate berry flavor. Weaker the first 5K and more concentrated in the final stretches.
Post-Workout Snack: An apple and some roasted nuts.

Two-time Olympic marathoner

Overall Diet: “I try to eat food high in iron and include lots of healthy fats like butter, coconut oil and avocados to support healthy hormone levels. I generally take in higher healthy carbs and moderate fat and protein.”
Prerace Dinner: 400 calories of brown rice pasta with 1 tablespoon of olive oil; a shake with two scoops of Muscle Milk. Eaten once at 6 p.m. and again at 8 p.m.
Race Fuel: Breakfast: 20 ounces of water, 200 calories of Cytocarb mixed with two scoops of Muscle Milk in 8 ounces of water; 1 tablespoon of almond butter; black coffee.
During the race: 8 ounces of Cytomax every 5K; gels mixed with 8 ounces of water instead of Cytomax at 10K, 20K and 30K.
Post-Workout Snack: Sweet potatoes after the good ones; doughnuts after the bad ones (he says with a laugh).

Olympic 10,000m bronze medalist, Olympic marathoner

Overall Diet: Nutrient-dense, minimally processed foods. “As a female, I also emphasize consuming iron-rich foods and plenty of good fats.”
Prerace Dinner: Usually consists of a whole grain or a potato; fish, steak or chicken; and vegetables.
Race Fuel: Breakfast: Irish oatmeal with creamer, banana, raisins, honey and nuts—and “coffee, of course.”
During race: 4 ounces of Gatorade every 5K.
Post-Workout Snack: KIND bar, electrolyte drink and an apple.