What is carb loading?
Carb loading is simply a strategy to increase the glycogen stored in your body. This involves a few days of eating more carbs than usual while decreasing exercise to reduce the amount of carbs you are using.
Carbohydrates are an important source of fuel for your body, for anaerobic and endurance performance. Carbs are stored as glycogen in your muscle and liver. Muscle glycogen provides the necessary fuel for energy metabolism in striated muscles, while liver glycogen supplies glucose to other cells and maintains blood glucose levels for brain function.
When carb loading, the number of carbs you eat ranges from 2.5-5.5 grams per pound of body weight per day. People often carb load a few days before an athletic event such as a marathon or a long race, specifically prolonged biking or running (~>90min). There may be no benefit for slightly shorter durations of exercise, including events lasting 60–90 minutes and is probably unnecessary for weight training or other exercise involving short bursts of activity. Dang it.
Fatigue during endurance events or prolonged anaerobic activity has been associated with low glucose levels in the muscle and in the blood. As muscle glycogen is depleted during a training bout, exercise will “feel” more difficult, and RPE will increase. Finding a way to keep glycogen levels up in the muscle delays the onset of fatigue, whether it be due to reduced pain with exercise (peripheral), preserved balance of brain chemicals (central), or a combination of both.
Classic 6 Day Method
This method involves an initial phase of approximately 3 days of glycogen depletion by eating an Atkins-type (low carb) diet and exercising to exhaustion. Meaning about 15% of your diet is carbs. This phase is followed by a period of high carbohydrate intake and reduced activity (~3 day taper).
New 6 Day Method
The newer methods do not involve a depletion phase, just reduced training and increased carbohydrate intake during a taper. This methods leads to less glycogen loading, but also less side effects (mood swings, overturning symptoms). The first three days your diet consists of 50% carbs and the last three days your diet consists of 70% 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.
Many athletes use the Classic Method as it seems more effective. Recent studies using new technology have shown that a depletion phase promotes greater glycogen storage which lasts for a longer period of time than carb- loading without a depletion phase. In support of earlier research, it appears that the depletion phase increases glycogen stores via 3 main pathways: 1) increased ability to uptake glucose; 2) increased storage rate; and 3) preferential fat metabolism and reduced glycogen oxidation (usage) rates.
How to Carb Load
Don't make the mistake of choosing carbs that are high in fats (chocolates, ice cream, etc), because that could cause weight gain or leave you feeling sluggish.
Experts often recommend that people who are carb loading eat 2.3–5.5 grams of carbs per pound (5–12 grams per kg) of body weight per day.
Recording your food intake can help you make sure you are eating the right amount. It is best to record your food intake and calculate how many carbs you’re eating.
Foods to Eat
White noodles with marinara sauce
Skinned white potatoes
Fruit, including bananas, oranges and watermelon
White flour, used in cooking
Low-fat energy bars
Of course, it is also important to keep up on eating protein to support your muscles. Focus on lean protein sources, such as fish, lean cuts of meat or poultry and fat-free dairy.
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
Creamy sauces, such as Alfredo sauce
Certain energy bars
Carb loading is used by athletes to increase exercise performance.
Carb loading involves two major components: increasing the carbs you eat and decreasing the amount you exercise.
Carb intake can range from 2.3–5.5 grams per pound (5–12 grams per kg) of body weight per day, but experts often recommend a narrower range of 3.6–4.5 grams per pound (8–10 grams per kg).
Carb loading may improve performance for exercise lasting more than 90 minutes, but it’s probably unnecessary for shorter-duration activities.
This strategy may not be useful for you if you are recreationally active, but not an athlete or competitor in long-duration events.
When you carb load, it may be best to choose familiar foods that are high-carb and low-fat to avoid stomach aches. You may also need to limit your fiber intake during these days.
If you perform long-duration exercise, you may want to experiment with carb loading before your next event to see if it can boost your performance.