Exactly How to Carb Load the Week Before a Marathon

If you’re running the Boston Marathon (or any marathon), what you eat this week can make or break your race.

And most runners get it wrong.

In this episode, I’m breaking down exactly how to carb load the right way—so you show up on race day feeling energized, not sluggish, bloated, or underfueled.

You’ll learn:

•  Why carb loading is NOT just a big pasta dinner the night before 
•  Exactly when to start (and how much to eat) 
•  What a full day of carb loading actually looks like 
•  How to avoid common mistakes that lead to GI issues mid-race 
•  What to eat the night before and the morning of your race 

If you’ve ever hit the wall, felt low energy late in a race, or just want to feel more confident going into race day—this episode is your game plan.

🎧 Hit play, then save this episode so you can come back to it during race week.

Or watch the episode on YouTube! 

Apply to work with Natalie for 1-on-1 nutrition coaching! 

Have questions or want to request a show topic? DM us @greenletes

Check out Natalie's book 📕: Planted Performance

Transcript

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Whether you're running the Boston Marathon or another marathon this season, you're soon to enter the carb loading phase. You've done all the training, you are so close to race day, but you don't want to mess up your fueling now. And I'm gonna help you get through this last week of fueling so that you feel amazing come marathon Monday morning. I'm telling you exactly how to carb load, what to eat, what to avoid, and how to do it right because so many people make carb loading mistakes and it can really cost you on race day. So let's start with what carbloading is. Most people think I'm just gonna eat a huge bowl of pasta the night before the race and I am set to go. But that's not necessarily carb loading. Carb loading is actually a three to four day strategy leading up to a long distance race like a marathon, giving your muscles and your liver extra carbs to store in something called glycogen. That is the stored form of carbs in your muscles and your liver. By taking in a lot of carbs for three to four days leading up to the race, you have extra stores, and that's gonna give you extra energy. So that's the strategy behind why we do carb loading. And this is based in science. There's been plenty of research to show that carb loading actually works when you do it properly and that the everyday athlete can do this. This is not just for elite athletes. We see a lot of nutrition strategies out there that are really fine-tuned for elite athletes, but the everyday athlete can do this. People are running, you know, three-hour marathons, which I would say is more than the everyday athlete, but four, five, six, however long it takes you to run a marathon, you can do carbloading and it can help you have extra energy during race day. Now, before we get into exactly how to carbload, I want to preface this by saying carbloating does not replace fueling during the run. But this is what you're gonna do the week leading up to the run, where you're tapering, you're not really running much, you're feeling antsy, you're feeling you don't like you don't really have a plan. This is your plan for the week before. And I will also say carbloating is not as easy as it sounds. It's not just eating a ton of bread and being like, this is delicious. I get to eat whatever I want. It's not super simple and it doesn't always make you feel great to be eating tons of carbs the week before, but it definitely helps on race day. So for my runners out there who like numbers, let's get into the numbers here. For carb loading, the strategy is to take in seven to ten grams of carbs per kilogram of body weight. If you're watching me on YouTube, I'm breaking out my calculator now so that I can put that into pounds for you. And we are gonna do this in pounds. So let's say you are 150 pounds. The way that you always figure out anything from kilograms to pounds is you divide by 2.2. So 150 divided by 2.2, you're about 68 kilograms. So let's times that by seven, seven grams of carbs per day. If you want to take that even a step further, carbs have four calories per gram. So if you did 477 times four, that means almost 2,000 calories from carbs per day. Now that may sound insane. Like I don't need 2,000 calories of carbs per day, but here's what the rule of thumb is when it comes to carb loading. Carbs should be 80% of your diet in the three to four days leading up to the race. That's what carb loading is. It's really loading the diet with carbs. Now, going back to what I said before, it's not necessarily an easy thing to do because eating 80% of your calories from carbs requires a lot of foods that you may not really eat on a regular basis, especially altogether. So let's give an example of what this actually looks like. Let's walk through the meals of the day. This is really gonna drastically shift based on your size, uh, your based on your size, your gender, how what your target is for race day. So obviously, you know, a small woman may be eating half the amount of calories and carbs than a larger man, or even vice versa. However, this is just an example. So let's say that we want to have, we're starting with breakfast. Basically, the way that I talk about food in general for plant-based athletes is that you're starting a meal with protein and you're building out. So generally, I would say pick with protein, what's your protein at breakfast, and then build out from there because there's plenty of carb-rich plant-based foods. Carb loading is different. What you're doing with carb loading is you are actually picking the carb and then you're building around it with more carbs. So let's say your breakfast starts with a bagel. Okay, you're having a bagel, that's a carb rich item. Then maybe you add a little bit of nut butter on it. It doesn't have to be all carbs, but then you're gonna add even more carbs on there, maybe a little nut butter, then you're gonna have maybe some slices of banana. And here's the other thing to keep in mind. When it comes to carb loading, you may have to add in drinks to get more carbs because you can only eat so much food. So, say you have the bagel with the nut butter and the banana and the drizzle of maple syrup, and it's still not getting you to really what you need, which is probably over a hundred grams of carbs at that meal. You can add in a drink. It could be a sports drink, it could be a glass of juice, it could be a glass of chocolate milk. Drinks are gonna help you get more carbs in there, as well as sauces, things like the maple syrup or a jelly or things like that. Now, I get it. This may sound like this is not the kind of food I want to eat normally. And the hesitation I hear from a lot of runners is that my body's just gonna store these and I'm gonna gain weight in the week leading up to the marathon. That's not true at all. Your body is storing it, and you may actually gain a pound or two, but you're gonna lose it and use it all during that race. So, yes, you may gain a little bit of uh glycogen weight, but it's gonna be gone by the end of this race. So let's go back to our day of eating. We had that breakfast, then you're gonna throw in a stack. What's the stack gonna be? It's gonna be carbs. So think of something like a granola bar, something that's very heavy in carbs, maybe 30 grams, not a protein bar, something that doesn't have a ton of protein and has a lot of carbs. Could be graham crackers, could be pretzels, anything that's really carb rich with not a ton of protein and fat. Let's talk about lunch. Lunch, maybe you'll start to add in a little bit more fiber, a little bit more protein, but you're still gonna rely heavily on the carbs. So maybe it is something like a rice bowl with some veggies, which also add the carbs. And don't be scared of starchy veggies like potatoes, carrots, and it could be fruit too, like apples, bananas, and then maybe a little bit of a protein like a like a tofu, but you don't even need it if you really wanna just kind of keep it really carb heavy. And then a sauce. You can drizzle on a teriyaki sauce. Put something on there that has a little more sugar than you would normally eat, because that's gonna give you the extra carbs. Later on the day, have another snack. Have a snack, even if it's just a glass of juice. If it's a glass of juice and a handful of berries. If you want to go for something really uh more carb rich, it could be a waffle. It could be a waffle with some maple syrup on it. You are doing this only for three days. If it feels uncomfortable, it could be even two days. But doing this loads your muscles with the carbs. And then for dinner, think back to your pasta dinner. You can have the pasta dinner, you can have something that's starchy with rice, you can have maybe just even a sandwich with a lot of bread, something that's really starchy, not too much fiber, because you don't want to overload your system with fiber, but something that's really carb heavy. And again, lean into the drinks. If you need coconut water, if you need a sports drink, if you need something to help you hit that carb target, it's going to help you. Here's the thing that many people may not tell you, but I'm gonna tell you here. Carb loading doesn't necessarily feel great. You eat a lot of carbs. Carbs digest quickly, but they don't keep you full. So you may eat this huge breakfast with all these carbs and then an hour later feel like you're hungry again. It's because these carbs are not keeping you super full, but they are filling your muscles with glycogen, which is what you need for race day. I personally don't love carb loading, which is funny because you would think that you love eating bread and pasta and all of these things, but I do see the benefit of it, and I think that it's helpful on race day. So keep that in mind. You may feel a little sluggish. Make sure you're drinking plenty of water with all of these carb rich foods, and know that after the race, you can go back to eating your healthy foods again. You don't have to eat like this. This is just for a three to four day period. The other thing to keep in mind, you should not be exercising a lot. This should really be a time of tapering. Tapering means like really reducing the mileage because you actually want the body to take those carbs and store them and not use them for exercise. So keep that in mind if you are doing a carb load that that's going to help you keep the glycogen stored is not exercising. If you're plant-based, which a lot of my followers are, you have a little bit of a leg up here because most plant-based foods have a good amount of carbs. Fruits, vegetables, beans, legumes, whole grains, those are all carb-rich foods. The one thing to keep in mind, the few days leading up to the race, you want to keep fiber to a minimum. You want to have enough fiber that you're able to go to the bathroom and stay regular, but not too much that you're upsetting your stomach in any way. So if certain foods like, you know, beans make you gassy, broccoli, cauliflower kind of make you bloated, stay away from those the day leading up to the race. If you're trying this carb load three to four days out and you feel like it's not really going as planned, really focus on the 48 hours before the race and keep three things in mind. One, drink your carbs if you have to. If you feel like you can't get enough in at a meal because there's only so many calories you can eat in a day, drink your carbs. Turn to sports drinks, turn to juice, coconut water. You can even just flavor water with some maple syrup and a little bit of lemon juice. You can drink your carbs to get those carbs in. Two, lower on the fiber. Keep the fiber low, have a little, but don't have too much. And three, don't be scared of foods that you once thought maybe weren't quote unquote good for you. Things like waffles, sugary cereal, you know, rice crispy treats, anything that you normally wouldn't eat because it's got a lot of sugar in it, that your body's actually taking that sugar and storing it up for race day. The night before the race, you have done everything right. Stick with something you know. Maybe it is that bowl of pasta. If you've done all the carbloading, just keep it simple. Don't do anything crazy. Don't eat anything fried, don't eat anything too spicy, don't eat anything too acidic. This is exactly what you need to do to finish up the carb load. That is where you're finishing it, right there. The next morning, what you have for breakfast actually is not really a carb load anymore. That's gonna get you through the first hour of your race. So, race morning, your game plan, two to three hours before, especially if you're running Boston, you're gonna have maybe a full breakfast. It could even be three to four hours before, because with marathons, you wake up a long time before because you have it takes a while to get to the start. So maybe it is something like a bagel with some nut butter and some peanut butter out, and you have that full amount of breakfast that you're gonna have. And then you bring some more carbs with you to the start of the race. This is where a lot of runners make a huge mistake. You want to have that pre-race breakfast that's three to four hours before, and then bring something with you to the start. Could be a gummy, could be gels, could be sports drink, could be raisins, could be dates, could just be an energy bar. Whatever works for you, something you've tried in the past, bring it with you. This is not necessarily the carb loading phase, but this is helping you get through the first hour or so. What should happen is having had that carb load in your system, and then you fuel, hopefully, throughout the race, you're gonna feel let like at mile 20. All of that comes together so that there is no hitting the wall for you. This is essentially why we're doing this. So I'm gonna go through a few mistakes that I want you to avoid. One, just waiting before. Waiting until the night before to carbload. Two, eating more fiber or something new. Three, eating something greasy the night before or even the morning of. Maybe you're in a different country and you go and grab a breakfast sandwich that's a little greasy. Don't do that. Four, just not eating enough or not feeling enough or not taking in enough carbs because you're scared that you're gonna gain weight or you're gonna store it. Trust me, you're not going to. Okay, so all of that is setting you up for this week going into the Boston Marathon. And if you are listening to this at a later date, this can set you up for any marathon. You just need to be intentional about the foods that you choose the week before and the morning of. If you want more carbloading tips and nutrition for runners, feel free to reach out to me. DM me at Greenlee's. Let me know what you're struggling with. And if you like this episode, send it to a runner friend, maybe someone who's running the Boston Marathon. Maybe you're planning on running it next year. Let me know. Remember, I am here to help. I want you to fuel early, fuel often, and don't be scared of carbs. Until next time, I'm Natalie, the host of Greenlee's. Thanks for listening.