How Much Sugar Should a Runner Eat?

Just a few decades ago, endurance athletes (along with the general public) labeled fat as the bad guy. Today, carbohydrates (carbs) are in the hot seat.

According to the rumors, carbs--namely sugar--are said to be unhealthy, cause weight gain, reduce the body’s ability to burn fat, contribute to diabetes, insulin resistance and cravings, cause energy crashes and, finally, negatively affect performance. Yikes! No wonder everyone is avoiding carbs like the plague. However, not all rumors you hear are true. And, when it comes to proper fueling, carbs actually aren’t the bad guys they’ve been made out to be.

Carbs are essential for optimal health and serve as the primary fuel for the body. Before you even lace up your shoes to run, your body requires 120 grams of carbs (about 500 calories) per day simply to fuel your brain, support your central nervous system and maintain red blood cell production and immune health.

During exercise, your body utilizes carbs for energy in the form of glucose. This fuel assists in fat metabolism, delays fatigue, promotes recovery and supports the central nervous system.

In high-intensity exercise (like a tempo workout), carbs are responsible for converting fat to glucose quickly; fat is burned in a carbohydrate-fueled flame. The proverbial “wall” or “bonk” runners refer to, occurs when glycogen (long-chain glucose stored in the muscle) reserves are depleted. And, in the absence of glycogen, no fuel is available to convert fat to usable fuel quickly.

On top of this, the body’s glycogen stores are limited. Fully stocked, your tank holds enough glycogen for approximately two hours worth of effort at moderate intensity. Keep in mind, the higher the effort, the more carbs you use, and the faster you burn through glycogen stores.

So, what you eat day to day and the timing relative to exercise directly impacts how much glycogen you have available in your “gas tank” at any given time. Adequate carb intake that matches activity level can safeguard your glycogen storage, muscle tissue, support blood sugar levels during exercise, optimize recovery and protect your immune system.

So how do you know how much to eat?

Some of the healthiest and fastest runners in the world consume a carbohydrate-rich diet, including the elite Kenyan runners who dominate the distance running world.

In conducting research for his book, “The Endurance Diet,” dietitian, writer and endurance runner, Matt Fitzgerald writes that elite Kenyan runners get 76 percent of their daily calories from carbs that come from fresh, unprocessed food sources.

While it’s OK to eat processed food on occasion, if you prioritize wholesome, nutrient-dense carb sources in place of processed, refined, or nutrient-poor choices most of the time, you can radically improve running performance and feel better, too. That’s because these types of carbs are complex, which means they break down into glucose a bit slower than simple sugars and provide vitamins, minerals and fiber. Being selective with your carb choices and strategic about the timing of your consumption, helps too.

For example, a morning runner should include carbs at breakfast and lunch but can taper off carbs at dinner and include more veggies and fruit. Exception: if it’s the night before a long, intense workout or race, don’t skimp on complex carbs at dinner.

For example, a 120 pound (54.5kg) athlete who ran for 3 hours would refuel with 20g protein and 40 to 60+ g carbs within 30 to 45 minutes, followed by a balanced meal within 90 minutes.

It’s common to have a decreased appetite following a hard workout. If you don’t feel hungry, refuel with a cold liquid that sounds refreshing and goes down easy.

Knowledge is power and the more you understand carbohydrates’ role in supporting your body, health, and active lifestyle, the closer you will be to achieving your goals. To recap, not all carbohydrates are created equal, and carb-timing is key to proper adaptation, recovery, and body composition optimization.

Consume carbs during your most active time of the day. Limit refined, sugary snacks and desserts but if you can’t kick that nagging craving – go for that sweet treat right after a workout or include post-meal to diminish the hormonal and blood sugar response, therefore, reducing the fat storage effect.

Reducing or eliminating carbs will not help you accomplish your goals for performance and wellbeing. In the long run, limiting a macronutrient or following a diet regimen that results in a negative energy balance will leave you empty and unsuccessful.