To Carb Load or Not to Carb Load – 5 Myths about a Runner’s Diet

You’ve probably heard the term “carb loading,” and now wonder if you should be gorging on high-carb foods right before a big race. Knowing more about the proper way to carb load (and nutrition myths vs. facts) for runners is the key to improving performance and staying on your A-game.

Myth 1: Only Drink Sports Drinks for Events Lasting Longer Than One Hour

To Carb Load or Not to Carb Load - 5 Myths about a Runner's Diet

You’ve probably heard that sports drinks should only be used for training or events lasting more than one hour. While this is generally true, sports drinks can be beneficial at any point during an endurance race. This is especially true if the exercise is intense or takes place in hot and humid weather.

The American College of Sports Medicine says competitive athletes can experience significant drops in glycogen stores and electrolytes during prolonged or intense exercise, even if the activity is less than one hour. Sports drinks can help prevent this, reduce fatigue, and maximize performance. Additionally, the Gatorade Sports Science Institute shows researching showing that consuming small amounts of carbs can boost performance for intense exercise ranging from 30 to 60 minutes in length.

Even drinking sports drinks or other forms of fast-digesting simple sugars before exercise boosts blood sugar and energy and can improve athletic performance. But for best results, skip added sugar from junk food and opt for sports drinks, dried fruit, energy bars, gels, or sports jelly beans containing electrolytes and fast-digesting sugars. Everybody’s glycogen stores are different, so the saying “one size fits all” doesn’t apply to sports nutrition. Listen to your body to determine when ingesting carbs is necessary.

Myth 2: More Protein Is Better

To Carb Load or Not to Carb Load - 5 Myths about a Runner's Diet


For endurance athletes, carbohydrates are the body’s main source of energy. While protein is important, especially during race recovery, the excess protein your body doesn’t use gets excreted. The Academy of Nutrition and Dietetics suggests that athletes consume 1.2 to 2.0 grams of protein per kilogram of body weight each day. That amount equates to 0.5 to 0.9 grams of protein per pound of body weight each day. For a 130-pound runner, that amount equates to 65 to 117 grams of protein daily. The Gatorade Sports Science Institute says ingesting just 10 to 20 grams of protein helps stimulate muscle healing or growth post-exercise but consuming more than that amount right after exercise provides little to no extra advantages.

While carbohydrates are the main fuel source during endurance sweat sessions, protein is a key nutrient needed for recovery. Athletes should choose lean grilled chicken breast or lean ground or sliced turkey, lean beef, eggs, fish, seafood, legumes, low-fat dairy foods like Greek yogurt, low-fat cottage cheese, low-fat milk or soy milk, tofu, nuts, and seeds.

Myth 3: Load Up with Carbs the Night Before a Big Race

To Carb Load or Not to Carb Load - 5 Myths about a Runner's Diet

It’s true that carb loading can be beneficial for certain athletes when done properly. This strategy involves slowly boosting your carb intake and scaling back on the intensity or duration of your workout three to four days before a big event. Doing this appears to help boost glycogen stores (carbohydrates stored in your muscles and liver). But you don’t have to load up on carbs right before an event to perform at your best. In fact, gorging on carbs the night before may actually hinder performance if you eat until you’re uncomfortably full.

Skipping carb loading doesn’t mean your performance will suffer. Mayo Clinic suggests carb loading can be beneficial for endurance athletes racing in events lasting longer than 90 minutes, but other athletes do well simply by eating half (or more) of their total calories from carbs.

Registered dietitian Dave Ellis with the American College of Sports Medicine (ACSM), suggests athletes eat between 3 and 5 grams of carbs per pound of body weight daily, and the Academy of Nutrition and Dietetics says ultra-endurance athletes training longer than four to five hours daily may require up to 5.5 grams of carbs (or more) per pound of weight daily.

To effectively carb load, Mayo Clinic suggests boosting carbs to 10 to 12 grams per pound of body weight (or about 70 percent of your total calorie intake) beginning three to four days before a race.

Myth 4: Reduce Sodium to 2,300 mg or Less Daily

To Carb Load or Not to Carb Load - 5 Myths about a Runner's Diet

Recommendations set by the Dietary Guidelines for Americans 2020 and the  American Heart Association are to limit dietary sodium to 1,500 to 2,300 milligrams per day to help prevent high blood pressure and heart disease. However, this recommendation doesn’t necessarily apply to athletes (especially endurance athletes) because they lose so much sodium in sweat. Gatorade Sports Science Institute says some athletes lose 10 grams (10,000 milligrams) of sodium by sweating in just one day of intense training.

That means athletes have a higher risk for sodium deficiency (hyponatremia), which can cause symptoms like muscle cramping, fatigue, bloating and upset stomach. Confusion, seizures, and loss of consciousness can also occur with low blood sodium levels. Many nutrition products like sports drinks and gels contain sodium and other electrolytes. That’s why taking them with you (use a running water bottle or handheld water bottle for sports drinks during long runs) stored in your hydration pack or other training pack is crucial. Pick a salty snack post-workout to replenish sodium.

Myth 5: Drink Protein During a Race

To Carb Load or Not to Carb Load - 5 Myths about a Runner's Diet

It may seem like the right thing to do to drink protein during a race, as protein is a key nutrient your body requires to function properly and maintain lean body mass. However, Gatorade Sports Science Institute says research shows drinking protein (as part of a sports drink) before exercise doesn’t provide performance benefits but may slow gastric emptying and create a chalky taste that makes getting in enough fluid a challenge. So, consume carbs from simple sugars before and during your race, and save the protein drinks for post-workout muscle recovery.