It’s Okay to Love Carbs—Your Body Needs Them

Spend a little time in the online fitness community and you’re sure to notice that no one can seem to agree on the proper way to fuel your body for a workout. Everyone’s got their own favorite diet buzzword and after a while it can be pretty hard to see through the smoke.

Let’s be clear: everybody (and every body) is different, but some scientific guidelines are universal. One of these guidelines is that if your fitness regimen includes high-intensity training of any sort (and studies suggest that at least some of your regular physical activity should be vigorous), you should not pass up on the carbs.

Not convinced? Let’s break it down.

Carbohydrates & Your Body’s Energy Silo

When we eat carbohydrates our body converts them into glucose—the main source of fuel for our brain and many of our bodies’ cells. What’s not immediately metabolized in the body is stored in the liver or in muscle in the form of glycogen. These glycogen stores are later accessed to provide fuel for the support of brain and/or central nervous system functions. They are also necessary providers of energy for any type of high-intensity physical activity.

It’s important to separate the role of glycogen from that of fatty acids. Fatty acids also act as stored energy for later use and are often cited as producing a higher level of energy on a per-gram basis than glycogen. While this may be the case, our brains require glucose to function optimally. Glycogen is also necessary and ideal for intense workouts as it is can become available for use more quickly and requires less oxygen when producing that energy—this makes glycogen ideal for aerobic and anaerobic activity.

What Happens When Glycogen Levels Are Depleted?

Not properly fueling up before a workout can not only set you back in your training, it can derail you altogether. At a minimum, you may not be able to push as hard during a workout and your duration may suffer. Summing up a pair of studies investigating the role of glycogen in resistance training programs, Todd Astorino (M.S­.) and Len Kravitz (Ph.D.) note that while it’s important to eat a balanced diet and not overdo it on carbohydrate consumption (since excessive intake can lead to weight gain), it’s equally important for individuals who are physically active—even on a recreational level—to be “concerned with maintenance of glycogen stores, since glycogen depletion may reduce work output and duration.”

Dr. Iñigo San Millán via TrainingPeaks.com found similar results in a lab study of competitive cyclists. Focusing on glycogen depletion, the study found that “about 30% of all [the] cyclists had sub-optimal glycogen levels and none of them knew about it.” The potential pitfalls of this depletion were also clear: “Since protein and amino acids are the building blocks of muscle, the latter may enter a catabolic situation (muscle breakdown). Essentially, the muscle ‘eats itself to feed itself’ by increasing the amount of protein and amino acids used for energy purposes.”

On the extreme end of the scale, individuals that continue to push hard in workouts, races and events well after glycogen stores have been depleted may experience hypoglycemia. Hypoglycemia occurs when blood glucose levels are low and may cause a person to experience “body tremors, weakness, anxiety, sweating, slurred speech, and eventually coma.” Athletes who are diabetic or have a history of eating disorders are particularly at risk, and anyone experiencing symptoms during an intense or long bout of exercise should immediately consume glucose—sports drinks, tablets or juice are good options.

Fuel Your Body Right

The average person should receive 50% of their daily calories from carbohydrates. Athletes—or anyone following a regular training program—should be particularly careful about their macronutrient levels: recommendations for carb intake for these groups range from 5 to 8 grams of carbs per kilogram of body fat per day, and intake should be adjusted depending on the nature, timing and intensity of the workout.

Before using these figures as an excuse to reach for the fries, keep in mind that experts recommend most of your carb intake should come from unrefined carbohydrate sources like whole grains, fruits and starchy vegetables—these have a slower digestion rate than their refined counterparts and keep you fuller longer. That said, if you need a quick burst of energy prior to a workout, pasta, rice or a bagel should work just fine.

When you’re planning a particularly long or intense session, it’s also important to ensure adequate repletion of glycogen levels during and after the workout—your body’s glycogen storage is limited, after all. Estimates suggest that the body can store about 1,800–2,000 calories of glycogen at a time; for most, these reserves can fuel 1.5–2 hours of strenuous exercise. Nutrition consultant Riska Platt recommends eating “50-100 calories every half hour of carbohydrates such as low-fat yogurt, raisins, or banana.” (And don’t forget to stay hydrated.)

After a workout, eating a combination of carbs and protein can help muscles recover and get you set for another intense workout the next day. This kind of post-workout refueling is less important if you’re not planning to exercise strenuously for a couple days, but keep in mind that regardless of your schedule, consuming a combination of carbs and protein (particularly in a 3:1 carbs-to-protein ratio) can assist with not only replenishing glycogen levels but with protein synthesis as well, aiding your body in building muscle tissue.

Rethinking Macro-Restrictive Diets

Our bodies evolved to flourish off of a combination of proteins, fats and carbohydrates. While some people may benefit from restricting one of these macronutrients more than the recommended amount, most of us will do best eating a balanced diet of meals made from whole foods. Athletes and active people, in particular, should avoid restricting their carbohydrate intake too drastically since carbs can act as a gateway to better overall performance.

If you’re still sold on a high-fat, low-carb diet (or any other diet that has you limiting consumption of a targeted macro), consider taking a multivitamin or supplement to support you in your health and fitness journey. And, of course, always consult with a doctor before jumping into any sort of restrictive dieting plan. The online fitness community can be a source of interesting information and great ideas, but it may not have your unique health needs and goals at heart.