Carbohydrate Load Diet-Mayo Clinic


A carb-loaded diet, also known as a carb-loaded diet, is a strategy that improves athletic performance in endurance events by increasing the amount of fuel stored in the muscles.

Carbohydrate load occurs when eating a high-carbohydrate “training diet” while reducing activity levels in the days prior to the event.


Every physical activity requires carbohydrates as fuel. In most recreational activities, your body uses existing energy storage as fuel.

But when you engage in long and intense exercise events, your body needs extra energy to continue. The purpose of carbohydrate loading is to reduce fatigue and provide the energy needed to complete an endurance event and improve athletic performance.

Carbohydrate loading is most effective when endurance athletes, such as marathon runners, swimmers, cyclists, or all three, are preparing for an event that lasts more than 90 minutes. Other athletes generally do not require a carbohydrate load. It’s usually enough to get about half the calories from carbohydrates.

Diet details

Role of carbohydrates

Carbohydrates, also known as starch and sugar, are the main source of energy for your body. Complex carbohydrates include legumes, grains, potatoes, peas, corn and other starchy vegetables. Simple carbohydrates are found primarily in fruits and milk, as well as in sugar-based foods such as candies and other sweets.

During digestion, your body breaks down carbohydrates into sugar. Sugar enters the bloodstream where it is transferred to individual cells to provide energy. Sugar is stored in the liver and muscles as an energy source, glycogen.

Increase energy storage

Your muscles usually store only a small amount of glycogen — enough to support you during recreational exercise activities. Exercising hard for more than 90 minutes can lead to muscle glycogen deficiency. At that point, you may feel tired and perform poorly.

However, the load of carbohydrates may allow you to store more energy in your muscles. This may give you stamina to go through a long endurance event. However, you will have to consume some energy sources during the event.

Carbohydrate load

Carbohydrate loading occurs one week before high endurance activity. Increase your carbohydrate intake to approximately 8-12 grams of carbohydrates per kilogram of body weight 1-3 days before the event. Reduce fatty foods to supplement foods rich in excess carbohydrates.

Also, reduce training 3-4 days before the event. The combination of eating more carbohydrates and tapering activity seems to boost muscle glycogen storage.

The number of carbohydrates you need depends on your total calorie goal and your sport. For most athletes, 5-7 grams of carbohydrates per kilogram of body weight per day is suitable for general training. (Note that 1 kilogram is equal to 2.2 pounds.) Endurance athletes may require up to 12 grams per kilogram.

Sample carb-loaded diet plan

This is a sample carbohydrate-loaded diet plan for athletes weighing 170 pounds (77 kilograms). It is based on 4.5 grams of carbohydrates per pound of body weight (10 grams per kilogram).

You can tailor your carb-loaded diet plan for this sample to your tastes and nutritional needs.

Sample carb-loaded diet plan
Item (amount) Carbohydrate (gram) Total calories
Milk, fat-free (12 ounces) 18 125
1 plain bagel (4.2 oz) 52 260
Peanut butter, smooth (2 tbsp) 7 191
Honey (2 tbsp) 35 128
Banana (1 in) 27 105
Morning snack
Calica raisins and almond cereals (1 cup) 74 360
Grape juice (12 ounces) 55 225
Milk, chocolate, reduced fat (12 ounces) 46 285
4 slices of white bread (1 ounce per slice) 49 266
Chicken breast, roasted without skin (4 oz or 1/2 breast) 0 187
Romaine lettuce, shredded (1/4 cup) 0.5 2
Red tomato slice (1/2 cup) 2 11
Mayonnaise, light (2 tbsp) 3 71
Tortilla chips, low fat, grilled (1 ounce) twenty three 118
Baby carrot (12) Ten 42
Afternoon snack
Low-fat fruit yogurt (8 oz) 47 250
Low-fat fruit granola (1/2 cup) 33 157
Blueberries (1 cup) twenty one 83
Cranberry juice, sugar-free (12 ounces) 42 156
Wild Atlantic salmon, grilled (3 oz) 0 155
Dinner rolls, whole wheat (2 rolls, 1 ounce each) 29 151
Milk, fat-free (12 ounces) 18 125
Salad, combine:

-Finely chopped romaine lettuce (2 cups)
3 16
-Bells or peppers (1/4 cup) 2 7
-Green apple, chopped (1 in) twenty five 95
-Dried cranberries (1/3 cup) 33 130
-Chopped English walnut (1/4 cup) Four 191
-Asiago cheese, shredded (1 ounce) 1 134
-Fat-reduced lunch salad dressing (2 tbsp) 6 55
Evening snacks
Strawberries (1 cup) 11 46
Sherbet, any flavor (1 1/2 cup) 78 78 416
total 754.5 4,543

Source: Nutritionist Pro, 2018


Carbohydrate loading can give more energy during endurance events. After loading carbohydrates, you may feel less tired and improve performance. However, carbohydrate loading is not effective for everyone.

Other factors can affect your athletic performance and interfere with the effectiveness of your carbohydrate loading strategy, such as your physical condition, degree of hydration, and intensity of exercise. Even with carbohydrate loading, you may feel muscle fatigue.

For men, a carbohydrate-loaded diet can increase the levels of glycogen stored in muscle to 100 percent of normal levels. To get the same effect as men, women may need to burn more calories than usual during a carbohydrate load.

Despite the carbohydrate load, the body needs to be replenished during endurance events to maintain blood sugar levels. To do this, regularly consume sports drinks, gels, bars, fruits, or hard or crunchy candies at a rate of 30-60 grams every hour or two during the event. Also, don’t forget to eat carbohydrate-rich foods to supplement your glycogen stores after an endurance event.


Carbohydrate loading is not suitable for all endurance athletes. It is advisable to consult a doctor or registered dietitian before starting a carb load, especially if you have diabetes. You may also need to try different amounts of carbs to find the one that works best for you.

A carbohydrate-loaded diet can cause the following discomforts and side effects:

  • Digestive discomfort. You may need to avoid or limit some high fiber foods 1-2 days before the event. Beans, bran and broccoli can cause gaseous cramps, bloating and diarrhea.
  • The blood sugar level changes. Carbohydrate load can affect blood sugar levels. If you have diabetes, monitor your blood sugar during training or practice to see what works best for you. Then consult your nutritionist or doctor to make sure your diet plan is safe for you.


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