By Coach Adolfo Salgueiro
When I started running marathons in the early-1980s, back when dinosaurs roamed the earth, guzzling carbs indiscriminately was the way of life. The more carbs you ate, the more energy you would have stored for your long run the next day. It didn’t matter if they came from a pizza, your sixth bowl of pasta or a handful of cookies. The point was to ingest in as much as you could.

Regardless of how much pasta you eat the night before, your body can’t store beyond its capabilities (Photo by Anna Tis, from Pexels)
The thought process was that if carbs were good for endurance, more carbs would be better. And many, many more carbs would the way better. I recently heard an interview with Dr. Tim Noakes, the influential South African sports scientist and author of several books on exercise and diet, where he regretted his role in the popularization of the carbo-loading myth. He said that if you had an earlier edition of his groundbreaking book The Lore of Running, published in 1985, you should rip off the entire chapter on nutrition, where he champs this topic. He now preaches a low carb, high fat diet.
Now that there is money to be made, running has gone through tons of research in the last couple of decades. Nutrition is one of the subjects with most studies and scientific papers. Therefore hydration and gel options have grown exponentially in the last few years. Same with pre and post-workout powders and supplements. None of this was available way-back-when. We still call “water stations” by this name because when they started, that is all they offered. Gatorade came later. Earlier runs didn’t even have water. But I digress.
The science on glycogen is a bit complex to get into it in this post, plus, this is not a peer-reviewed paper for publication. There are plenty of resources available to explain what glycogen is and how it is metabolized to produce the energy that will push you forward. What is important to know is the new, science-based approach, about how to practice the proverbial carbo-loading.
Most runners are well familiarized with the term glycogen, the most immediate source of energy while we run. Anecdotally, I must have heard that word for the first time about 15 years ago, even though glycogen was discovered in 1857, four years before Abraham Lincoln became President.
In the early eighties there was this theory that if you depleted your body from carbohydrates the week of the marathon and about 3 days prior you started consuming carbs indiscriminately, your body would absorb more and thus have a bigger reserve. Despite the fact this silly theory has been disproven, it is still practiced by some marathoners today, to atrocious results. The amount your body can store is finite. So, regardless of how much pasta you swallow the night before, you won’t be able to collect more than what your body’s capacity allows.
Carbs are very important for a runner, thus the carbo-load. We do so to restore the glycogen stores in our muscles and liver. Just by being alive, our body burns through its glycogen. They deplete faster with activity. We need to replenish them to provide our body with quick fuel to burn during our runs. You could train your body to burn fat instead of glycogen as its primary source of fuel but that is beyond the scope of this post.

It is not just about carbs. They have to be the right carbs (Photo by Dana Tentis, from Pexels)
Assuming you are well hydrated, appropriately fed and in good health, your body has all the resources it may need to run from a 5K to a half marathon. There’s no need to overthink those aspects of your race unless it is an extremely hot or humid (or both) day. Beyond that, each mile is pushing your body closer to its reserve limits. And when the reserves get depleted, you hit the no-longer-so-mythical wall. Therefore, for longer races a hydration and fueling strategy is imperative.
Now, the other important point to consider is that not all carbs are created equal. Stuffing yourself with Oreos, Doritos and donuts is not carbo-loading. Those are simple carbohydrates that are broken down immediately and enter the bloodstream as sugars. They do not get stored for later use in your muscles or liver, thus, contributing nothing to what you should be trying to accomplish. This is the reason most sports drinks and gels are packed with sugars and simple carbs. So they can be tapped immediately by your system to produce energy. You wouldn’t carbo load with those.
What you’d rather be doing is consuming complex carbohydrates, such as brown rice, quinoa, oats, sweet potatoes, vegetables, and whole grain pastas. They take longer to break down and get stored in your muscles so they can be used later, like when you are running/racing. All this works better if you prepare your system, so these products become a compliment to your body resources and not the only source of energy production for long distance running.
Time has come to change our view on the old science. Time has come to adopt what the new research has shown to work. Let’s move forward, then.
Great as usual!
Thank you for that comment. I invest a lot of time and work very hard on my blog, so these comments help me a lot.
Good insight into this important topic. As you correctly state, this myth of carboloading has been in the popular culture for too long. Thanks Adolfo
Thank you for your input on this topic. It is time, indeed, to embrace the new science on this subject.
Thank you Coach Adolfo!! Yes, I see this. I learned in 2019 the hard way about eating too many carbs the night before. But, there are some runners that swear by it, probably mentally they are programed and there bodies react well to it. I love the idea of sweet potato since is easier to digest. Thank you so much once again.
Thank you for your comment, Nancy… Sometimes we learn our lessons the hard way. As long as the lesson is learned, we can count it as a positive experience.
Adolfo – another home run & valuable info. I will remember to follow your counsel for the Miami Beach 1/2.
Thank you for always reading my blog posts. I put a lot of effort into them and this makes it worth the while.
Thank you Adolfo for this. I still carb load, I switched it up a bit not only night before, the entire week, just as I do with water, Gatorade zero and electrolytes the entire week of my race you know I’m an ultramarathoner. There was one occasion I ate chicken the night before 3 years ago when I was out of town and couldn’t find Pasta. I do like the idea about the sweet potato. Thank you. Oh with my recent race this past weekend , I informed my friend to carb load she stated it’s a myth so there it goes just as your blog stated. Well, it works for moi, I guess it’s a mind thing. Lol 😆 Thanks for all the additional tips.
Carbo loading is not just cramming the night before your race, it has to be a deliberate practice throughout your training. And, as with your friend, pasta is not for everybody, so use only what works for you.