Sports Nutrition 101: Carbo Loading Before an Endurance Event

A sports nutritionist explains the best carbo loading strategies

“The idea behind carbo-loading is that by strategically manipulating when and how much carbohydrate you eat, you can store more carbohydrate, or glycogen, in your muscles allowing you to go further before depleting,” says Heidi Skolnik, a certified dietitian-nutritionist and owner of Nutrition Conditioning, Inc.

However, Skolnik explains that when it comes to the “best” carbo loading strategies, there are several different schools of thought.

“One that remains very practical is to taper the week before a race but continuing to eat carbohydrates as you did during training,” she says. “In essence, because you are not depleting carbohydrates during taper, you will store more, and will start race day fully stocked, without feeling ‘weighed down’”.

So the basic idea is to maintain or slightly increase your carbohydrate intake in the weeks and days leading up to an endurance event, like a marathon or an ironman race, even though your training volume will begin to decrease.

Skolnik recommends loading up on carbohydrates from foods like fruits, vegetables, beans, sweet and white potatoes, milk and yogurt, and whole grains.

“Eat these during meal and snack times the week before a race,” she said. Noting that runners and other athletes may have “discretionary calories” that leave room for loading up on carbs from less nutritious foods, like cake or ice cream for example.

And for the day before your race, Skolnik suggests avoiding any foods that you’re not used to and also limiting spices.

“Do not increase fiber if you are not used to fiber-rich foods,” she added. “And some people tend to reduce fiber the day before, but that is a very individual choice.”

This is a strategy that many athletes use for avoiding race day digestion issues, which are especially common for runners participating in endurance events.

“On race day, make selections that will be easy to digest, not cause gastric upset,” she said. “Balance of nutrients is not important at this time. Having some protein early in the day or morning along with adequate carbohydrate can help you feel satisfied without getting too hungry before the race.”

She also recommends making sure that you’re hydrated and that your body has an adequate amount of sodium, too.

Your race day nutrition is all about balance, so make sure not to overdo any one aspect, especially the carbohydrate component.

“One of the biggest mistakes I see is that athletes load [carbohydrates] too much and feel weighed down race day,” Skolnik says. “Or, and some people tolerate this better than others, follow a strategy that limits carbohydrate early on in the week to help deplete and then super compensate with a ‘loading” phase.’ This can really wreak havoc with mood and appetite regulation.”

She continues, “It just cannot feel good. Again, some athletes swear by this route but many do not tolerate it well and do not realize there are other options to approach the task and still start well fueled for the big day.”

What to Eat Before a Marathon: 5 Pros Share Their Favorite Meals
Marathon Training: 5 Tips for Staying Motivated
Marathon Training: 4 Things to Remember When You Start Tapering