The ultimate guide to carb loading for your next marathon, half marathon or triathlon for maximum energy levels.
If you’re gearing up for a marathon or any type of long-distance race, you’ve probably heard that carb-loading can help maximize performance. But carb-loading for a marathon is more precise than just eating pasta and bagels. There are things to know about carb-loading properly and efficiently.
This article discusses why and when you should carb load, how to do it properly, and the best foods to eat when carb-loading.
What is carb loading?
Carbs are the primary fuel source for exercise, making them incredibly important for athletes. During exercise, the body relies on two forms of carbs for fuel–dietary carbs (the food you eat before the race) and glycogen (the body’s source of stored carbs).
The purpose of carb loading is to train your body to store up as much glycogen as possible to extend energy levels during long endurance activity.
Usually, glycogen provides energy for the first 30-45 minutes of exercise, but loading up on carbs in the days before a race may expand that window.
In other words, carb loading is like filling up your gas tank to the tippy top so it takes longer before you reach “empty”.
During long events, like marathons or triathlons, carb loading can help keep energy levels up throughout the event. You still have to fuel during a long-distance race, but carb-loading may prevent a severe energy dip.
Is it necessary to carb load before a marathon?
The idea behind carb loading is to store up as much glycogen as possible for long-lasting energy during a race. You do not need to carb load for a marathon, but doing so can help maintain energy levels during the first few miles of the race.
Carb loading has been proven to boost energy levels during a marathon. Without carb loading, you may need to take in fuel after the first 60 minutes of a marathon. With carb loading, you may have more sustained energy through the first 90 to 120 minutes of a race. Either way, you should have a mid-race fuel plan.
How many carbs do I need for a marathon?
On a regular day, about 45-60% of calories should come from carb-rich foods, like fruits, vegetables, grains, beans and legumes. Carb loading recommendations suggesting increasing carbohydrate intake to about 80% of daily calories.
Although chowing down on bread and pasta may sound fantastic, eating 80% of calories from carbs is more tedious than you think, and you may feel full and bloated.
An easier way to think about this is to aim for 4 grams of carbs per pound of body weight. For a 120 pounds person, that’s 480 grams of carbs per day.
Begin carb loading 2 to 4 days before a race to give your muscles time to build their glycogen stores.
In addition, do not exercise in the 2 to 4 days leading up to a race, so you do not use up the extra glycogen in your body. Exercise depletes glycogen stores, and this counteracts your carb-loading efforts.
You may feel a little heavy and weighed down, and you may even gain a few pounds, but don’t worry because those carbs will get used up during the race.
Best carb loading foods
The best carb-loading foods are ones that are high in carbs. Don’t eat any foods that may upset your stomach–some people stay away from high-fiber foods, like beans or cruciferous veggies. That said, you still need some fiber in your diet to keep the digestive system moving. You do not want to end up constipated for race day!
Eat plenty of high carb grains or starchy vegetbles, like pasta, rice, bread, potatoes, corn or squash. Also include some beans, legumes, vegetables and fruit in your diet.
To achieve the recommended 80% of calories from carbs, you may have to drink some juices, sports drinks, chocolate milk or coconut water. These beverages provide carbs without filling up the stomach.
Some athletes also eat sugary snacks, like jelly beans, licorice, pancakes with maple syrup, cereal, pop tarts, and energy bars. Eating more added sugar than normal is perfectly fine for the 2 to 4 days of carbo-loading.
Avoid fried or fast food during the carb-loading phase, since they can upset your stomach.
Carb loading meal plan
Here is an example of a carb loading meal plan for a 150-pound person, who needs to eat around 600 grams of carbs per day.
Breakfast:
- 1/2 cup dry oats, made with 1/2 cup low-fat milk (1%) and 1/2 cup water. Topped with 1/2 cup mixed berries and 1 tablespoon of nut butter
- 1 banana
- 8 ounces orange juice
- Carb total: 125 g
Mid-morning snack:
- 2 Nature Valley Oat n Honey Bars + 4 Medjool Dates
- Carbs: 90 g
Lunch:
- Sandwich: 2 slices of white bread, hummus, sliced veggies
- 1/2 cup roasted chickpeas
- 1 cup grapes
- 8-ounces chocolate milk (or soy chocolate milk)
- Carb total: 150 grams
Mid-afternoon snack
- Medium sweet potato (microwaved), topped with cinnamon
- 1 ounce dark chocolate
- 8 ounces coconut water
- Carb total: 80 gram
Dinner
- 1.5 cups cooked white rice + 1.5 cup cooked butternut squash + 4 ounces tofu or tempeh
- side salad (about 1-2 cups of lettuce and veggies combined)
- 16 ounces sports drink
- Carb total: 155 g
As a vegan, my diet consists of approximately 70% of carbohydrates. At my last marathon I felt as though my carb loading wasn’t very effective.
How do you carb load prior to a marathon if your diet already consists of so many carbs?
That is a GREAT question! You can increase your carbs even more in the 3-7 days leading up to a marathon. Aim for 80-90% carbs, if possible. It’s difficult to do, so try adding in carbs in beverage form, like juice, sports drink, coconut water, etc. And you can also add a little bit of extra sugar to your meals, like honey or maple syrup.