What is carb loading?

What is carb loading?

A carbohydrate-loading diet, also called a carb-loading diet, is a strategy to improve your athletic performance for endurance events by increasing the amount of fuel stored in your muscles.

Carbohydrate loading occurs when you eat a high-carbohydrate “training diet” at the same time that you scale back your activity level in the days before an event.

Any physical activity requires carbohydrates for fuel. For most recreational activity, your body uses its existing energy stores for fuel.

But when you engage in long, intense athletic events, your body needs extra energy to keep going. The purpose of carbohydrate loading is to give you the energy you need to complete an endurance event with less fatigue, improving your athletic performance.

The number of carbs you can eat ranges from 2.3–5.5 grams per pound (5–12 grams per kg) of body weight per day. If you weighed 154 pounds (70 kg), that would work out to 350–840 grams of carbs per day

For most athletes, 5 to 7 grams of carbohydrate per kilogram of body weight daily is right for general training. (Note that 1 kilogram equals 2.2 pounds.) Endurance athletes may need up to 12 grams per kilogram.

Types of Carb Loading

Classic 6-Day

During the first three days of this program, you exercise while consuming a low-carb diet that gets about 15% of its calories from carbs

The combination of exercise and low carbohydrate intake decreases your body’s glycogen stores.

During days four to six of this program, you consume a high-carb diet that gets about 70% of its calories from carbs. You also reduce exercise on day four and perform no exercise on days five and six.


For the first three days, this program involves eating a moderate-carb diet that gets about 50% of its calories from carbs. This is followed by three days of a high-carb diet, with about 70% of calories from carbs

Throughout these six days, you gradually decrease the amount you exercise. During days four to six, you only perform 0–20 minutes of exercise per day.

Classic 3-Day

This program is shorter and simpler than the six-day programs.

At the beginning of the three days, you perform one exercise session until your body is exhausted, For the remainder of the three days, you perform no exercise while consuming a high-carb diet that gets about 70% of its calories from carbs.


The one-day program is the simplest of them all.

You do not exercise for one day, and you consume a high-carb diet of about 4.5 grams per pound (10 grams per kg) of body weight.



Carbohydrate loading may give you more energy during an endurance event. You may feel less fatigued and see an improvement in your performance after carbohydrate loading. But carbohydrate loading isn’t effective for everyone.

Other factors can influence your athletic performance or interfere with the effectiveness of your carbohydrate-loading strategy, including how fit you are, how well you hydrate and how intensely you exercise. Even with carbohydrate loading, you still may feel muscle fatigue.

For men, a carbohydrate-loading diet can increase the levels of glycogen stored in the muscles as much as 100 percent of your normal amount. Women may need to consume more calories than usual during carbohydrate loading to get the same benefits as men do.

Despite carbohydrate loading, you still need to replenish your body’s energy during endurance events to maintain your blood sugar levels. You can do this by periodically consuming sports drinks, gels, or bars, fruit, or hard or chewy candies during your event at the rate of 30 to 60 grams every hour or two. And don’t forget to eat carbohydrate-rich foods after your endurance event, too, to replenish your glycogen stores.

Foods to Eat and Avoid During Carb Loading

To get the recommended amount of carbohydrates, you should focus on foods that are high-carb, low-fat and don’t have too much fiber.

Foods to Eat


  • Low-fiber cereals
  • Fruit juices
  • White noodles with marinara sauce
  • White bread
  • Fruit jelly
  • White rice
  • Fruit smoothies
  • Skinned white potatoes
  • Applesauce
  • Pretzels
  • Fruit, including bananas, oranges and watermelon
  • White flour, used in cooking
  • Sherbet or popsicles
  • Sports drinks
  • Low-fat energy bars

Of course, it is also important to have protein to support your muscles. Try to focus on lean protein sources, such as fish, lean cuts of meat or poultry and fat-free dairy.

What’s more, eat foods you enjoy and that are familiar to you. Try to find the best compromise between the recommendations and foods you enjoy.

Many people eat high-carb foods that are high-fat too. It is best to avoid these during carb loading.

Foods to Avoid


Below are some examples of foods that may seem high-carb but are also high-fat and therefore inappropriate for carb loading.

  • Creamy sauces, such as Alfredo sauce
  • Muffins
  • Crackers
  • Chips
  • Cookies
  • Pizza
  • Brownies
  • Ice cream
  • Pastries
  • French fries
  • Donuts
  • Certain energy bars