“I feel like I’ve heard 60, I’ve heard 90, someone said 120, but then you might deal with stomach problems.”

That’s what one athlete told me in a session this year. Some version of it comes up with almost every athlete I work with. How many carbs per hour is the question I get asked more than any other, from first-time marathoners to riders lining up for 200 miles of gravel.

Part of the confusion is a good problem to have. We are in this era of slam as many grams of carbs as you can, which is great because it’s very different than 10 years ago, when it was like here, have a sip of water and hope for the best. But somewhere between “hope for the best” and “slam as many as you can,” the useful answer got a little lost.

So let’s walk through what the ranges actually are, where they come from, and how to figure out where you fit in them.

The short answer

The general sports nutrition ranges look like this:

• Under an hour: you don’t really need to fuel during. The caveat is that if you aren’t fueling during, what you eat before and after needs to be spot on.
• One to two hours: 30 to 60 grams of carbohydrate per hour.
• Over two hours: 60 to 90 grams of carbohydrate per hour, coming from mixed carbohydrate sources.

That last part, mixed carbohydrate sources, is doing a lot of the work. It’s also the reason the range stops at 90.

Why the range tops out at 90: the two doors

Every gram of carbohydrate you take in has to get from your gut into your bloodstream before your muscles can use it. I like to think of that as walking through a door.

Glucose has its own door. On average, we can process about one gram of glucose per minute through it. That’s roughly 60 grams an hour, and that’s the ceiling if glucose is all you’re giving it.

Fructose uses a different door. I think of it as a yellow door, and it only opens about once every two minutes. That’s roughly half a gram a minute, or about 30 grams an hour.

When both doors are open, you get 60 plus 30, which is 90. That’s where the top of the 60 to 90 range comes from. If everything in your pockets is one kind of sugar, you’ve got a line forming at one door while the other one sits empty.

When that line backs up, the carbs that can’t get through stay in the gut. Your body pulls water in to dilute them, and that’s where a lot of the bloating, sloshing and race-day stomach stories start.

If you want to check what you’re working with, flip your gel or drink mix over and look at the ingredients. Glucose, dextrose and maltodextrin go through the glucose door. Fructose goes through the yellow one. Cane sugar (sucrose) is one of each stuck together, so it uses both.

Where most athletes actually land

The range goes up to 90, but that isn’t where most of the athletes I work with live. I find that most folks are really happy between 60 and 75 grams per hour, if they’ve trained for it. For a lot of people, 75 ends up being a sweet spot.

I very rarely have athletes go up to the high end of 90 to 100. That isn’t because 90 is wrong. It’s because 90 is a ceiling, not a target.

Consistency beats the peak

This is the part that gets lost in the noise. Sure, you can totally hit 90 grams of carbs per hour. But can you do that for six hours? Probably not.

Picture a long gravel day. At hour two, 90 grams an hour feels great. By hour six, you’re forcing down sips of a bottle you can’t stand anymore, your stomach is sloshing, and eating anything at all starts to feel like a chore. Compare that to someone who sat at 70 grams an hour from the first pedal stroke to the finish line and never missed a feeding.

If we can find a number you can be consistent at, that’s going to be so much more impactful than hitting 90 some of the time. It’s also easier to build up than it is to pull back. Starting a little lower and adding more goes a lot better than starting too high and trying to recover once your gut has already said no.

What about the people doing 120?

You’ve probably seen it. A pro posts their race-day numbers, and suddenly 120 grams an hour is the number everyone’s asking about.

Here’s the thing about those athletes: they’re also putting out the power to support that. The work they’re doing creates the need for that many carbs, and they’ve spent a long time training their gut to handle it. Their number is a reflection of their output and their training, not a standard the rest of us are falling short of.

I don’t think more always equals better here. The goal is finding the amount that works for you, that you can stay consistent at, and that keeps you feeling good the whole way.

How to build up

Your gut is trainable, and that’s the good news in all of this. The way you get there is gradual.

1. Start where you are. If you’re newer to fueling, or you’re currently not taking much in, 30 to 60 grams an hour is a great place to begin. If you’ve been fueling a bit already, 50 is a solid starting point.
2. Add 5 to 10 grams per hour, per week. Maybe you go from 50 up to 55 and that feels good. You go up to 60, still good. Then you get to 65 and your body’s like, “Hang on a sec.” That’s information, not failure. Hang out at the last number that felt good for a bit before trying again.
3. Practice on easy days too. Fuel your long rides and runs even when they’re easy and lower intensity. That’s what teaches your stomach to handle that amount of carbohydrate, so race day isn’t the first time it’s seeing it.

What 60 grams actually looks like

Grams per hour can feel abstract until you see it in your pockets. Everything counts toward the total: your drink mix, your gels, your chews, and whatever real food you bring.

• One bottle of drink mix plus one pack of chews. For example, a scoop of Skratch Sport Hydration Mix in your bottle and a pack of Skratch Energy Chews gets you to about 60 grams.
• Two gels plus some sips of drink mix. Most gels land somewhere around 20 to 40 grams each, so check the label on yours.

One thing to keep in mind as you add more gels: bring more water with them. Those carbs need fluid and sodium to get where they’re going, and a concentrated gut is an unhappy gut.

Finding your number

The ranges get you in the right neighborhood. Where you land inside them depends on how long you’re out there, how hard you’re working, and what your gut has been trained to handle.

There’s a more individual way to set your number based on the work your rides actually demand. That’s what we dig into inside the Gravel Performance Nutrition Course and in 1:1 sessions. If you’re tired of guessing between 60, 90 and whatever number showed up on your feed this week, that’s where to start.