How to Carb Load in 100 Words or Less
Also known as glycogen supercompensation, this pre-event strategy is easier than we're taught to believe.
There are few sports nutrition concepts more needlessly complicated than “glycogen supercompensation” or, as we plebs call it, carb loading.
I admit I’ve dished out my share of convoluted pre-event feeding instructions over the years. But the times, they are a-changin’. My field agents have provided additional intel and, as a result, I’ve pivoted towards the side of simplicity. Mind you, my previous recommendations weren’t wrong; they were just too fancy.
So, without further ado, here’s how to carb load for your next big event:
Three or four days pre-event, increase your carbohydrate intake with satisfying-but-not-gluttonous meals focusing on whole grains and starchy veggies. Snack if you’re hungry between meals. Stick to foods you’re familiar with. It’s not an excuse to eat garbage, but if you really want curly fries or pecan pie, now is the time. On race day, have a roughly 300-calorie breakfast, three(ish) hours pre-event and a gel on the starting line. If you don’t have time for a meal, have a banana or other piece of fruit upon waking and a gel on the starting line.
95 words. Bam! Go crush your race!
In case you want to know more…
During long, hard efforts, you burn more carbs than you can absorb, so it’s always smart to cross the start line packing as much fuel as you can cram into your system.
We have less than 20 calories worth of blood sugar (glucose) circulating at any given time, so we have a back-up fuel supply called glycogen, a complex carb that the body stores in your liver and your muscles. When your glycogen stores are full, you can do about 90 minutes of intense activity before you run out.
If you exercise with some degree of intensity on a regular basis, it’s unlikely that you operate at max glycogen all the time, so it’s a good idea to top off before your marathon, gravel grinder, or triathlon.
If you take your training seriously, you probably taper your workouts before any big event to let your muscles properly recover. (If not, well, sad for you.) By eating more carbs (and calories in general) during this period of reduced activity, you maximize your ability to replenish your glycogen stores. That’s carb loading.
A brief history of carb loading.
In 1967, a group of Swedish scientists with swingin’ names like Björn and Lars-Göran introduced the strategy of topping off glycogen before a big event. Ever since then, various protocols have floated around. You’ll often see research showing benefits from low-carbing at the start of a taper week, followed by jacking up the carbs during the second half of the taper. Other research shows that “well-trained” athletes can skip that low-carbing part.
(You see that term “well-trained” thrown around a lot in the literature. What does that even mean? I’m more “well-trained” than the guy I left in my dust two miles ago, but I’m less “well-trained” than the guy who dropped me five minutes into the race. IMHO, it’s a problematic term in endurance athlete circles.)
Happily, we needn’t fret over such vagueries because, as Dr. Asker Jeukendrup points out in this graphic, loaded glycogen levels tend to level out at around 60 minutes into the activity you loaded for, regardless of your loading strategy. In other words, it doesn’t matter too much how you carb loaded. You just need to do it.
Boys versus girls.
Further complicating matters is the debate over how men and women respond to carb loading. Back in the eighties, researchers determined that women burn more fat than men during endurance events. They also concluded that women can’t increase glycogen stores by carb loading. Then, in 2000, one of these researchers, Dr. Mark Tarnopolsky, qualified that by claiming that female athletes actually do benefit from carb loading when they consume >8g of carbs per kilogram of body weight daily. A 2001 study in the European Journal of Applied Physiology confirmed that female athletes can, indeed, benefit from carb loading.
The reason for this discrepancy is that the original research didn’t look at total carb calories consumed. Instead, it looked at what percent of the diet consisted of carbs. Because the female athletes sampled were not eating enough over all, they were also not consuming adequate carbs to replenish glycogen. In Tarnopolsky’s follow-up, subjects were fed a meaningful amount of carbs—and the loading worked.
Don’t diet while tapering.
Once you enter your taper week, you need to eat—regardless of your gender. You’re not going to lose meaningful weight in the week before your event—and any attempts to do so could hurt your glycogen stores. You might also end up low-balling protein, which will inhibit muscle recovery.
You might end up losing a pound or so, but in exchange for weaker muscles and less energy.
Keep in mind that every gram of glycogen brings with it about three grams of water, so there’s a good chance that you’ll put on few pounds of water weight when carb loading. This is completely normal and beneficial. Be ready for it and if you're going to get weird about it, avoid the scale leading up to race day.
What to eat, exactly.
Much of my advice riffs off the work of Australian sports nutrition researcher Dr. Louise Burke, who recommends “10-12 g/kg/day over the 36-48 hours prior to the race.”
But are you seriously going to do all that math? I certainly won’t. If you follow the 95-word recommendation from the start of this article—eating to satisfaction with an accent on carbs—you’ll probably hit that 10-12 grams per kilogram number and then some. And you won’t have to stress about it.
Here are some foods to lean into.
Potatoes
Sweet potatoes and yams
Oatmeal and other whole grain cereal
Any and all beans and lentils
Brown rice, barley, and other cooked grains
Quinoa
Whole grain pasta (including couscous)
Whole grain bread (bagels, tortillas, crackers, etc)
Fresh fruit
That’s just the healthy stuff mind you. It’s also okay to indulge a little. Don’t eat yourself sick, but if you’ve spent the last few months eating super clean, here’s a moment when being naughty doesn’t matter that much. After all, you deserve to luxuriate a little before the mindless torture you’re about to subject yourself to.
Because you’re just a few days out from your event, it’s generally a good idea to stick to foods you know when carb loading. That should help you avoid any new food gastric upset.
Finally, don’t overdo calories in the final hours before you start. You should be glycogenterrific by now, so your pre-event meal just tops off the tank. A basic, carb-focused breakfast like oatmeal or waffles followed by three hours to digest should work. If you don’t have time for that, no problem. As I said, you’ll already be pretty loaded up. This is just a topper, so eat whatever you can handle. A piece of fruit is a good choice.
And suck down a gel at the start line if you want to look pro.
If you have other proven carb loading strategies—or some fancy science you’d like to toss around, please hit me up in the comments!