Stop Ditching Carbs—Here’s Why

Recent diet trends encourage you to completely ditch carbs in favor of a high fat, high protein diet. While omitting carbohydrates can be an effective way to jump start weight loss, for runners and endurance athletes it can spell disaster when it comes to athletic performance. I’ve had my own experience with low carbohydrates diets when I participated in the Whole30 Challenge and for a time, adhered to the Paleo guidelines to the detriment of my running in both instances.

Why We Need Carbohydrates

Carbohydrates are an essential energy source—especially for runners who depend on readily available energy—in the form of glucose, to sustain short bursts of activity. Carbohydrates are also essential to initiate fat burning that sustains longer, endurance activities.

“Carbohydrates are a critical source of energy for endurance athletes and forgoing carbohydrates can leave athletes fatigued and thus cause their performance to suffer,” explains Registered Dietitian Jamie Sheahan of The Edge Sports and Fitness in Burlington, Vermont. “The body must have a certain amount of carbohydrates available in order to metabolize fat so at best no carbohydrates on board is a recipe for a lackluster performance and at worst a complete a total bonk.”

This is especially true of female athletes, who don’t respond well to the traditional carbohydrate loading prior to a race.

“Until recently, most studies on carb-loading in athletes were conducted on male subjects and it was simply assumed that the results applied across the board regardless of gender,” says Sheahan, MS, RD.  “Thanks to more recent research, however, we have found that this could not be further from the truth,” she added, siting that women typically get 56 percent of their energy from carbohydrates (as opposed to men, who get 67% from carbohydrates) and 41percent of their energy from fat (compared to 29 percent for men.)

According to Sheahan, a much more effective way for female athletes to fuel for endurance events is by focusing on “capping off their glycogen stores” as much as possible in their daily nutrition so that they are ready to tap into fat reserves (remember those fat reserves can’t be accessed without adequate carbohydrates) during a longer event like a half marathon or marathon.

What Happens When You Ditch Carbs

“Forgoing carbohydrates can leave athletes fatigued and thus cause their performance to suffer,” says Sheahan, which confirms my own experience with low-carbohydrates diets. When eliminating most carbohydrates while adhering to Whole30 and Paleo guidelines,  I found myself feeling sluggish both during intense running (intervals on the track) and during easy to moderate efforts. My body seemed to crave what it “couldn’t have.” I wasn’t necessarily hungry, but simply felt dissatisfied by the food I was eating. It was hard to eat enough food to achieve a feeling of satiety—even when I was eating all steak and avocados I could manage. It wasn’t until I ditched the restrictive rules and began incorporating  more carbohydrates in the form of whole grains, like sprouted breads, quinoa and farro that I began to feel satisfied. 

I have since changed my approach not just to my daily nutrition, but to fueling runs by “topping off” my glycogen stores with a quick carbohydrate snack 15-30 minutes prior to all of my runs regardless of the how great or how little the distance I will run. Which means that my early morning runs are no longer “fasted” as they had been for a long period of time. Fueling my body has changed the way I feel on my runs and allowed me to perform better, and contrary to what one might assume there has been no weight gain from the addition of these high carbohydrate snacks. Sheahan encourages athletes to get creative their source of carbohydrates,  siting black rice, faro and freekeh as a few beneficial grains.

Reviewing Your Diet

If you find yourself falling short of your running goals when it comes to your ability to finish a race feeling strong, you may want to take a look at your diet and adjust your carbohydrate intake, both the amount and frequency. As female runners, it is especially important that our bodies are supplied with enough carbohydrate to sustain short, intense efforts and also initiate the fat burning that is so clearly essential to running farther and longer.