Carbohydrates are the chief fuel source for the body, and it is stored as glycogen, which is mostly present in the liver and muscles. The body uses the stored glycogen as the primary energy source during moderate to high-intensity workouts. However, the system can only store a specified amount of glycogen at once, and the stores become depleted via exercise as it is used to fuel it.
Carb loading is a nutritional approach for increasing the body’s glycogen stores above normal. It comprises eating more carb-dense foods than usual and decreasing exercise for several days.
This method is beneficial for periods of high-intensity exercise that last longer than an hour, but for those doing shorter spans of workouts or less intense ones, carb loading may not be helpful. This method is popular among endurance athletes who want to fuel their body with extra fuel it requires to go the distance.
Read this article to learn more about how carb loading works, strategies, and foods to eat.
What Is Carb Loading?
Carbohydrate loading, or carb loading, is a dietary approach that involves remarkably increasing the intake of carbohydrates in the days leading up to high high-duration endurance event lasting for 90 minutes or more. The main goal is to maximise the amount of glycogen stores in the liver and muscles.
Glycogen is the body’s primary fuel source during sustained aerobic exercise. But the scenario is under normal conditions, your body can only store a limited amount of glycogen, adequate to power about 90–120 minutes of moderate to intense workout. Once stores are depleted, fatigue sets in, a phenomenon athletes usually refer to as "hitting the wall" or bonking.
Carb loading helps avert this by boosting your glycogen reserves beyond typical levels.
How Carb Loading Works?
Phase 1: Depletion and Training (Optional):
This is an older version of carb loading, which involves reducing carb intake and performing high-intensity workouts to deplete glycogen stores. However, this phase has not been practised due to discomfort and minimal health incentives.
Phase 2: Tapering and Carb Increase (3–4 Days Before Event):
Slow down on the intensity of the workout and give time for the muscles to recover.
Increase carbohydrate intake by about 7 to 12 grams of carbs per kg of body weight per day.
Pay attention to easily digestible, low fiber foods like white rice, pasta, bread, fruits and energy drinks.
Race Day:
Have a light, high-carb meal about 3–4 hours before the event (e.g., oatmeal with banana, toast with honey).
Avoid high-fat and high-fibre foods that may upset your tummy.
Benefits of Carb Loading
Carb loading, when done correctly, can provide several key performance benefits:
Combats Fatigue
Ample reserves of glycogen help muscles to work longer before fat and protein are used, mainly for fuel, which are slower to metabolise.
Also Read: What Happens To The Body When You Stop Eating Carbohydrates?
Improves Endurance
Several studies have revealed that this approach helps athletes to improve their performance by 2–3%, which can make a significant difference in long sports events. Additionally, athletes feel that they need to put less strain when the body is completely fuelled, which helps them in maintaining a steady pace throughout the sports event.
Prevents 'Bonking'
Those who are following this are less likely to experience a sudden energy crash in the middle or end of their race.
Best Carbohydrate Sources for Carb Loading
White pasta, rice, and bread
Bananas, applesauce, and dried fruits
Pancakes and low-fiber cereals
Energy bars and sports drinks
Potatoes and sweet potatoes (peeled)
Potential Side Effects and Downsides
While carb loading is effective for many, it may result in certain side effects:
Glycogen usually binds with water; for every gram of glycogen stored, the body holds about 3 grams of water. Athletes may gain 1–2 kg of water weight during carb loading, which is normal and temporary.
Rapidly increasing carbohydrate intake, especially from fibre-rich foods, can lead to bloating, gas, and indigestion. That’s why easily digestible, low-fiber carbs are recommended.
Carb loading is specifically helpful for sports activities lasting for 90 minutes or longer. For shorter races or strength-based sports, the benefits are minimal.
In people sensitive to insulin or with blood sugar issues, a sudden spike in carb intake can lead to highs and lows in energy. Consulting a nutritionist is advised.
Conclusion
Carb loading is not a magical trick, but it’s a science-backed strategy when done appropriately that can significantly enhance performance in endurance events. The key lies in timing, the type of carbohydrates you consume, and understanding your own body’s response.
If you’re preparing for a race that demands hours of effort, consider practising carb loading in training to see how your body reacts. And for best results, work with a sports dietitian to personalise your approach.
(This article is reviewed by Kalyani Krishna, Chief Content Editor)
Author Profile:
M Sowmya Binu:
With over 15 years of expertise and a Postgraduate degree in Nutrition, M Sowmya Binu is a seasoned professional in the field of nutrition. Specialising in tailoring personalised diet plans, she underscores the significance of a balanced approach to health, emphasising the integration of medication with dietary intake for holistic wellness. Passionate about equipping individuals with knowledge to make informed decisions, Sowmya adeptly develops insightful content encompassing a wide array of topics, including food, nutrition, supplements, and overall health.
References:
Carbohydrate-loading and exercise performance. An update
J A Hawley 1, E J Schabort, T D Noakes, S C Dennis
https://pubmed.ncbi.nlm.nih.gov/9291549/
https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/carbohydrate-loading
Carbohydrate Loading Practice in Bodybuilders: Effects on Muscle Thickness, Photo Silhouette Scores, Mood States and Gastrointestinal Symptoms
Wilson M A M de Moraes 1,2,✉, Fernando N de Almeida 1, Leonardo E A dos Santos 3, Kathleen D G Cavalcante 3, Heitor O Santos 4, James W Navalta 5, Jonato Prestes 1
https://pmc.ncbi.nlm.nih.gov/articles/PMC6873117/
