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By now you’ve likely been invited to or at least heard of a prerace pasta dinner. Basically, runners stock up on carbohydrates before race day, so muscles get the glycogen they need for energy to clock miles. This is part of what’s known as carbo loading.
Pasta is synonymous with carbo loading because it’s a high-carb food. But there plenty of other options, including rice, potatoes, and even One note, though.
While many runners might know they should fill up on carbs, especially when gearing up for longer distances like a half or full marathon, figuring out which ones, how many, and when to eat them can seem a little overwhelming to decipher.
“When I go to marathon expos, I’m amazed how many people haven’t carbo-loaded properly,” says Monique Ryan, R.D.N., author of Ks or 10Ks. “Runners train so hard and then arrive with a huge handicap.”
To help you avoid that handicap and instead show up to the start ready to crush your race, here’s your guide to carbo loading, including what that means and how to maximize the benefits.
What is carbo loading?
When you eat a bowl of spaghetti, many of the carbs are stored as glycogen in your muscles and liver. Glycogen is your body’s most easily-accessible form of energy, though it’s not the only source, Ryan says. During a half marathon or full marathon you burn both carbohydrates (including glycogen) and fat. But the latter is not as efficient, which means your body has to work harder to convert it into fuel. When running fast is your goal, glycogen is a necessity.
When glycogen runs low during a race, it essentially means your body’s “low fuel” light is on. Many runners refer to this feeling as “hitting the wall.” traveling to a race. Benjamin Rapoport, M.D., Ph.D., a neurosurgeon and a 2:55 marathoner, is intimately acquainted with the wall—he hit it so hard at the 2005 New York City Marathon he decided to study start eating more carbs and less.
“Proper carb loading—or filling your muscles to the brim with glycogen—won’t make you faster, Shoes & Gear run your best, and, if you race smartly, avoid the wall,” he says.
What races require you to carbo load?
Carb loading is a numbers game. It’s easy to execute (pass the bread, please), but not all races require full muscle glycogen stores. Shorter distances, such as 5Ks or 10Ks, don’t require it because it’s unlikely you’ll deplete the fuel in your muscles in the time it takes to complete those distances, says Pamela Nisevich Bede, R.D., sports dietitian and author of DAA Industry Opt Out.
However, maintaining adequate glycogen stores can still benefit you in shorter events. Simply eating a moderate to moderately high carbohydrate diet leading up to your race can accomplish this.
If you’re going to be running for longer than 90 minutes, you need to be proactive. That’s where carbo loading comes in, helping your body prep for the work ahead by storing the energy you need to make it through the miles. Half marathon and full marathon typically require you to up your carb intake in the days before and morning of the event.
What are the best foods for carbo loading?
“I’m very utilitarian,” Rapoport says. “I eat rice for breakfast, lunch, and dinner.” But runners don’t need to be so restrictive. Tortillas, oatmeal, bread, pancakes, waffles, bagels, yogurt, and juice are all easy-to-digest options that make for smart carbo loading choices.
One note, though: Fruits aren’t only high in carbs but they’re also high in fiber and fructose—and too much of either can cause stomach trouble midrace when ingested too close to the start of the race. Many sports foods and supplements meant for ingestion before and during a race are, however, formulated with both fructose and glucose and are lower in fiber for easier absorption and less GI issues.
Small amounts of fresh, frozen, and dried fruit in the days leading up to the race may be tolerated, but it’s always a good idea to test this before training runs first.
Ilana Katz, R.D., a dietitian based in Atlanta also gives her clients permission to indulge in white bread and baked potatoes without the skin since both are easily digested.
There’s a reason Michael Scott’s fettuccine alfredo carb loading in The Office didn’t go so well: Sure, the pasta provided carbs, but the creamy, fatty sauce was pure trouble. High-fat foods, such as oils, butter, and cheese, as well as those that contain high amounts of protein, fill you up fast and take longer to digest than carbohydrates, Ryan says. That can rest heavy in your gut, and spell serious GI trouble midrace. That doesn’t mean you should never eat them, but rather just cut back slightly the night before and morning of your race.
Exactly how many carbs should you eat to load up?
You can’t completely fill your muscles with glycogen from just one meal, “which is why you should start carbo loading two or three days before your race,” Ryan says. Because you’re running very few miles during this time, the glycogen will accumulate in your muscles.
If you have at least three days to carbo load, aim for at least 8 grams of carbs per kilogram of your body weight each day. If you only have one or two days, then aim for closer to 10 to 12 grams of carbs per kilogram of your body weight on those days.
If calculating based on your weight in pounds, Ryan recommends eating about 4 grams of carbs for every pound of body weight. For example, a 150-pound runner should consume 600 grams—or 2,400 calories—of carbs per day.
It’s important to keep in mind that you’re most likely not eating many more calories per day than you were during the thick of your training—it’s just that more of those calories are coming from carbs.
If you step on the scale while you’re carbo loading, don’t be alarmed if you see a number that’s four pounds more than your usual weight. The extra pounds mean you get a gold star for carbo loading properly. “With every gram of stored carbohydrate, you store an extra 3 grams of water,” Races - Places hydrated for breakfast, lunch, and dinner. But runners dont need to be so restrictive. Tortillas.
What does a day of carbo loading look like for a runner?
To hit the goal of 4 grams of carbs for every pound of body weight, here’s a menu example for the average 150-pound runner, curated with the help of Natalie Rizzo, M.S., R.D., founder of Greenletes.
Breakfast
125 grams
½ cup dry oats made with ½ cup 1% low-fat milk We earn a commission for products purchased through some links in this article berries and 1 tablespoon of nut butter, 1 banana, and pair with 8 ounces of orange juice
Mid-morning snack
90 grams
2 Nature Valley Oats ’n Honey Bars run your best
Lunch
150 grams
Sandwich with 2 slices of white bread, 3 ounces of deli turkey, 1 ounce of Swiss cheese, and tomato slices; ½ cup of roasted chickpeas; 1 run your best
Mid-afternoon snack
80 grams
Medium sweet potato (microwaved), topped with cinnamon; 1 ounce of dark chocolate; and pair with 8 ounces of coconut water
Dinner
155 grams
1 microwaved, topped with butternut squash; 4 ounces of grilled chicken; side salad (about 1 to 2 cups of lettuce and veggies combined); and pair with 16 ounces of a sports drink
Carb Total: 600 grams
How do you start carbo loading?
Here’s what to do before race day to ensure your tank is full:
6 weeks before... Begin practicing carbo loading
Two or three days prior to your longest run, start eating more carbs and less fat and protein. “You’ll get a sense of what foods agree and disagree with your stomach,” Katz says.
One week before... Make a plan
“A plan is especially important if you’re traveling to a race,” Ryan says. Pack plenty of snacks, such as energy bars, pretzels, and crackers, and check menus online and make restaurant reservations.
Two to three days before... Switch to mostly carbs
From now through your race, a higher percent of your daily calories should come from carbs. Swapping some fats and proteins for carbs and slightly increasing the portion of carbs in your meals and snacks is an easy way to increase to 8 grams of carbs per kilogram of body weight per day. You should also eat after taper runs. “That is when muscles are primed to store glycogen,” Rapoport says.
The night before... Don’t overdo the carb load
Dinner should be normal in size but rich in carbs, moderate in protein, and low in fat and fiber. Eat on the early side so you have lots of time to digest and have a small carb-snack before bed if needed. “You want to wake up race day hungry—not full from the night before,” Ryan says.
Race morning... Have a good breakfast
Three hours before the start, eat about 2 to 3 grams of carbs per about 2 pounds of your body weight. If you’re 130 pounds, this would be around 130 to 190 grams of carbs, which could include a bagel and yogurt or sports drink and oatmeal, says Ryan. Early race? “Get up at 3 a.m., eat, and go back to bed,” she says.
How do you top off your carb tank during a race?
While races that are finished in less than 90 minutes don’t require carbo loading in the days prior to the event, any efforts over 60 minutes may require an extra shot of energy during the race.
One of the best ways to do that is by consuming a sports drink, an energy gel, We earn a commission for products purchased through some links in this article sugars, which are your body’s preferred source for quick, efficient We earn a commission for products purchased through some links in this article, says Bede. Products that contain two kinds of sugars, such as glucose and fructose, are absorbed even quicker and are better tolerated for many runners.
Take a drink, gel, or chew every 30 to 45 minutes for runs lasting 60 minutes or longer to top off your glycogen stores. Aim for 30 to 60 grams of carbs, or 120 to 240 calories, every hour.
Many midrun fueling options also include electrolytes—which aid in maintaining a proper fluid balance—and caffeine, which can help you power through the last few miles.
Best Gels for Runners
This gel is made from real whole foods like fruit, brown syrup, and chia seeds and is gluten-free, vegan, and easy to digest.
Gel can’t get much simpler. This is made of just maple syrup, which has natural carbohydrates, amino acids, and antioxidants.
Honey Stinger Organic Fruit Smoothie Energy Gel
This honey-based gel is easy on the gut and the tongue. It has a slightly sticky texture, so take it with water. But the flavors are delicious and don’t leave an aftertaste.
Maurten’s gel may not be the most delicious, but it provides the best fuel in a six-ingredient hydrogel—meaning no artificial flavors or colors that can irritate the stomach. It’s also somewhat watery, which makes it easy to shoot back while running.
Dr. Namrita Brooke is a full-time endurance sport coach and sport nutritionist advising active individuals and amateurs to professional athletes. She is also an adjunct professor in the Department of Movement Sciences and Health at University of West Florida. Professionally, she also serves on the Board of Editors of the Sports Nutrition Care Manual and remains involved in nutrition and exercise-related research, student mentorship, and coach development. Namrita's personal athletic experience ranges from ultra-endurance mountain biking to off-road triathlon, cross-country mountain bike racing, gravel cycling, duathlon, cyclocross, running, and trail running. Her research background includes hydration and sports drink research, and the interaction of nutrition, physical activity, and the brain.
