We’re just four days away from the annual Blue Cross Broad Street 10-Miler here in Philly (yikes), which got us thinking about a popular pre-race ritual: carbohydrate loading. Both Hope and I have participated in various distance runs from 10-milers to half marathons over the last few years, but admittedly, never really thought about carb loading in depth. We knew carbs fueled our bodies before a workout, but as we became more nutritionally conscious, we started to really contemplate the validity of stuffing our faces with pasta the night before a race.

Previously, when friends and family suggested eating bowls [on bowls] of pasta the night before a big race, we’d quickly oblige—no questions asked. Now, we would never experiment with altering our diets without first doing extensive research on the topic. So, with another big race quickly approaching, we started wondering—does carb loading really work? What even is carb loading, really? And what’s the right way to go about it? Well, we’ve done our research. And we’re glad we did. Turns out going HAM on a big bowl of pasta the night before a race might not be the best approach to reaching peak performance and getting that PR on race day.

What is carb loading?

Carb loading is a strategy used by endurance athletes, such as runners, to maximize energy by increasing the amount of glycogen, or stored glucose, in the body. Our muscles and liver use glucose for energy, and carbs are easier for our bodies to convert to glucose compared to fat or protein. Research has shown that increasing carb intake—and therefore, glucose storage—can improve performance by 2-3%. IMPORTANT: This is only true for endurance events lasting 90 minutes or longer, because your body doesn’t start to run low on glucose until after about 90 minutes of exercise.

How do I carb load correctly?

Typically, the carb loading process doesn’t all happen in one day (or one meal). Athletes traditionally begin the process 6-7 days before an endurance event, by essentially depleting their glucose storage through a low-carb diet for a couple of days. This typically also includes high-intensity workouts out on these days, to help reduce the body’s carb dependency. Following depletion, the body can store glucose at above-normal levels, so about 3 days prior to an endurance event, athletes will switch to a high-carb diet and simultaneously decrease exercise to maximize glucose storage.

This sounds a lot more involved than just scarfing down bread and pasta the night before a race, huh? In fact, this night-before approach could leave you feeling bloated and lethargic on race day. Guilty.

How many carbs is enough carbs?

Since nutrition is personal and many factors come into play here, the answer to this question is different for everyone. But typically, about four grams of carbs per pound on the body is recommended per day while carb loading (multiply your weight by 4, and that’s how many grams of carbs you should aim for per day).

The key to this is to make sure you aren’t also increasing your daily fat and protein intake along with your increased carb intake. You still want to consume roughly the same amount of calories per day to avoid any unwanted weight gain, which could hinder your performance come race day. Aka, ditch the creamy sauce and extra cheese on that pasta, stat.

So, what should I eat while carb loading?

Think fruits and veggies, whole grains, lean protein and healthy fats. If you suffer from stomach issues (holler!), it’s important to limit foods that are high in fiber or contain dairy and/or refined sugar—all which could mess with your digestion (and that pre-race poop we all know and love). Bananas and sweet potatoes are great examples of high-carb, low-fiber fruits and veggies. The key to all of this, as with most things in life = balance. And balance [sadly] doesn’t = a big bowl of pasta covered in butter and cheese.

Per our earlier point about carb loading only being effective for endurance exercises of 90 minutes or more, perhaps you don’t have to carb “load” before the Broad Street Run this year. If you plan on finishing in an hour and a half or less, you’ll finish before your body hits “the wall”—aka, glucose depletion—and be golden. Just make sure you refuel after finishing the race, so your body can begin building up it’s glucose storage once again!

Best of luck this weekend, runners!!

This post is part of our WTF series—where we’ll break down some of the latest food, fitness, and health + wellness trends blowing up your Instagram feed.