The importance of carbs, protein & calories for running performance

Long runs provide the perfect setting for existential questions to arise.

What is the meaning of life? 

What is the purpose of running? 

Why do my legs feel like they’re each 300 pounds? 

These questions ran through my brain on my long run last week. 

I’m at the tail end of my half marathon training, with the race next weekend (woohoo!)

I’m fairly certain every human has experienced a time when they weren’t as motivated to train or reach their race goals, and that’s the state I’ve been in recently. 

It’s manifested in slower paces, less running days, and negligence with diet. During marathon training, I was super dialed in with what I needed to be eating. Now, I’m eating mostly protein and really slacking in the carb department, which is an important key to answering my 300lb leg question.

When you’re training for a race, carbs are queen.

I realized halfway through my run that I had just had a salad with protein for dinner the night before, and a protein bar (+2 cappuccinos) for breakfast. And I remembered I felt super light and energetic when I used to have a wrap with rice & protein with a piece of chocolate the nights before my marathon training runs. For the past couple of months, I’ve been negligent with my carbs.

Dietary concerns for runners & other athletes are different than those for sedentary folks, and it can be super time-consuming and murky to sift through the research for how to properly fuel. I think every runner everywhere has struggled at some point to find the perfect breakfast, or the best post-run meal, especially with all the GI distress that can come with the sport. 

I wanted to round up the basic nutrition information from current research on fueling for runners. Of course, everyone is different, and it’s super important to experiment with these things to see what works best for you. Also, I would love to point out that I am not a dietician and thus you should absolutely consult with one if you need more info!

Fueling is not just what you eat for breakfast, it’s how you nourish your body before,during and after your runs.

We can break it down below. (I apologize, all of these studies talk about grams per kilogram of bodyweight, so I did my best to convert to USA terms!)

Throughout training season

• While training, endurance athletes should eat about 7-10 grams of carbohydrates per kg of bodyweight per day (or roughly 3 - 4.5 g per lb of bodyweight)

• This should increase to 10-12 grams of carbs per kg of weight per day in the two days prior to your race.

Just before your run

• Mayo Clinic says you should eat 200-300g of carbs 3-4 hours before a run….but I don’t know anyone who would willingly get up at 2 am to shove down some carbs before an early morning race

• A more realistic approach: an hour and half before your race, snack on a small carb-rich meal with a little bit of protein or fat. I like to do toast with PB and berries with maple syrup drizzled over. The key is just prioritizing carbs!! 

During your run

• If your run is >1 hour, it’s helpful to eat 30-60 grams of carbs per hour.

• If you don’t like gels (which is common!) you can literally eat candy!

• I know a guy who literally eats a PB&J during his long runs. It’s completely savage & impressive. He doesn’t stop running while he’s eating. 

After your run

• It is so important to replace your glycogen stores by eating carbs and eat up some protein, because running definitely has an effect of breaking down your muscles (aka it’s considered a catabolic activity.) Race days are one of a few days a year that I love to eat burgers for this reason! (nothing against burgers! I just don’t really care for them other than after a really long, hard run!)

• Try to do this shortly after your run (a lot of sites tell you 30 minutes after a run…to me this just isn’t practical because of GI distress in a lot of runners.) 

• I know how hard it can be to eat after a run - your stomach is in shambles a good portion of the time. I’m all for listening to my body, but sometimes you just have to force yourself to eat a little bit. 

Lastly, some real talk.

Fueling properly for a run is incredibly important, especially if you plan on doing this stuff long-term. 

Running does not build up your bones. Strength training does. And stress fractures are a risk with long-distance running. So if you’re running regularly or doing any type of endurance sport, please please please make sure you are getting enough calories and prioritizing carbs and proteins to fuel yourself. Running takes up an incredible amount of calories, and not replenishing them can put you at-risk for stress fractures. 

If you ever feel like me, with the 300lb pair of legs, or if you’re tired no matter how much you sleep, or you find yourself dreading your workouts, take a peak at your nutrition- there could be some answers in the way that you eat!