Carbs & Runners: Friend of Foe?

by Nancy Clark, MS, RD, CSSD

Runners create many reasons for limiting their intake of seemingly “evil” carbohydrates: I don’t like sandwiches … Pasta is so “heavy” … I’m staying away from gluten … I avoid any foods with added sugar … I prefer to eat two veggies at dinner instead of a veggie and a carby food. And, most often I hear: Bread is fattening!!! Anti-carb sentiment has pervaded my entire career as a sports nutritionist. While some fads have come and gone, the “carbs are bad” fad remains engrained in the brains of even elite athletes. I am (again) encouraging you to reconsider your stance.

• Despite popular belief, carbohydrates are not inherently fattening. Excess calories of any kind are fattening. Excess calories of bread, bagels, and pasta are actually less fattening than excess calories of cheese, butter, and olive oil. That’s because converting excess calories of carbs into body fat requires more energy than does converting excess dietary fat into body fat, That means, if you want to be gluttonous yet suffer the least weight gain, indulge in fat-free frozen yogurt instead of gourmet ice cream!

• To allay any confusion, let’s clarify what carbs actually are. Carbohydrates include both sugars and starches. Carbs are in fruits, vegetables, grains, and milk (lactose). Sugars and starches all digest into the simple sugar glucose. Glucose travels in your blood and, with the help of insulin, gets taken into muscles and stored as glycogen for fuel. Runners who restrict carbs commonly complain about “dead legs.”

Sugars and starches are biochemically related. For example, an unripe fruit, such as a banana, is starchy. As it ripens, it becomes sweeter; the starch converts into sugar. Similarly, vegetables, such as peas, are sweet when young. Their sugar converts into starch as they mature.

All carbs—both sugars and starches—are excellent sources of fuel. Both “carby” bagels and sugary candy end up as glucose in your blood and feed your muscles as well as your brain. Whether you are running or lifting weights, a carb-rich sports diet (with adequate protein) can enhance your performance.

Whole grains, fruits, and veggies offer abundant vitamins, minerals (electrolytes), and other health-promoting nutrients. Refined sugar, however, offers little nutritional value. Yet, dietary guidelines say 10% of daily calories can come from added sugar. That’s at least 50 grams of sugar for most runners and allows for some “fun foods.”

Sugar-avoiders please note: the 3 grams of added sugar in 2 tablespoons of peanut butter will not negate peanut butter’s health-promoting fiber, protein, and anti-inflammatory fats. Nor will the sugar in chocolate milk diminish its value as a helpful recovery fluid after a hard workout. Please look at the vitamins, minerals and protein that come along with the added sugar, not just the sugar itself.

Sports drinks, gels, and sports gummies are little more than refined sugar. That’s not bad; it’s exactly what the body wants during extended hard exercise. Even though refined sugar adds “empty calories” to a sports diet, runners need not eat a perfectly sugar-free diet to have an excellent diet. There’s a time and a place for sweets.

The messages that carbs are inflammatory, fattening, and bad for you is targeted at sedentary people who consume excessive calories, often from highly processed foods. For those unfit (often unhealthy) people, excess carbohydrate can contribute to elevated blood glucose, which triggers the body to secrete extra insulin. Consistently high insulin can be inflammatory and lead to nasty health issues. Yet, most runners can handle carbs with far less insulin than the average American—and without carbs causing “sugar crashes” or weight gain.

The most common reason for “sugar crashes” (hypoglycemia) among runners relates to running out of fuel. The shakiness and sweats are because the athlete did not eat enough carbs to maintain normal blood glucose levels and the brain has to demand a quick fix—sugar! One marathoner credited the sugary gel he took at Mile 16 to cause him to “crash.” More likely, he needed more just one gel to meet his energy needs.

For runners who routinely train hard 3 to 5 days a week, carbs should be the foundation of each meal. The International Olympic Committee’s recommendations for a performance diet include far more carbs than many runners consume via fruit, salads, and cooked veggies. Baseline targets for a 150-pound runner are:

375 g carb/day for ~1 hour of moderate exercise
450 g carb/day for ~1-3 hours of endurance exercise
525 g carb/day for >4-5 hours of  extreme exercise

This comes to about 100 to 150 grams carb per meal, which equates to about 400 to 600 calories of grains, fruits, and/or veggies per meal. This menu exemplifies what 450 grams of carb “looks like”:

TIME

MEAL

CARB (g)

SAMPLE  MEAL               

6:30

 

7:30

Pre-exercise snack

 

Post-exercise Breakfast

  40

 

 

110

Clif Bar                                    

--1.5-hour bike ride—

1 cup dry oats cooked in
1 cup milk
1 large (9”) banana
drizzle honey                      

11:30

Early lunch

125

Sandwich        

Fruit yogurt                    

4 fig newtons                      

3:30

Hearty Snack

  45

Dried fruit (in trail mix)

Latte                

7:30

Dinner

 

130

Chicken

2 cups (brown) rice     

1 cup cooked carrots

8 Hershey Kisses 

If your daily menu lacks starchy foods, experiment with adding grains to each meal and snack. You just might discover how much better you can feel and perform!


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Sports Nutritionist Nancy Clark, MS, RD counsels both casual and competitive athletes in Newton MA (617-795-1875). Her best-selling Sports Nutrition Guidebook is a popular resource, as is her online workshop and books. For more information visit www.NancyClarkRD.com.


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