Fueling on the move: how many carbs per hour for long efforts

Most amateurs lose their long days not in the legs but in the stomach, or rather in what never reached it. They under-eat on the move, fade in the final hour, and blame fitness. Fueling during long efforts is one of the highest-return skills in endurance sport, it is trainable, and almost everyone starts out doing far too little of it.

Why fueling on the move matters so much

Your body stores only a limited amount of carbohydrate, enough for somewhere around ninety minutes to two hours of hard work. Past that, if you have not been topping up, you run low, your pace falls off a cliff, your head goes foggy, and the classic bonk arrives. Taking in carbohydrate while you ride or run keeps that tank from emptying, so you can hold power and make good decisions right to the end.

This is not about the whole day's calories. It is specifically about getting usable carbohydrate into working muscles during the effort, when your own stores cannot keep up with demand.

You do not bonk because you are unfit. You bonk because you ran out of fuel and did not put more in.

How much, and what kind

The right amount scales with how long and how hard you are going:

• Up to about an hour: you generally do not need to fuel during the effort. Your stores cover it.
• One to two and a half hours: aim for roughly 30 to 60 grams of carbohydrate per hour.
• Longer and harder efforts: experienced, gut-trained athletes can use 60 to 90 grams per hour, and some go higher still on big days.

Above roughly 60 grams an hour, the type matters. A mix of glucose and fructose uses two different absorption pathways, so you can take in and actually use more than glucose alone allows. That is the science behind the modern high-carb gels and drink mixes. Practically, spread the intake across the hour in small regular amounts rather than one big hit, and take it with water.

Train the gut like any other system

Here is the part people miss: your gut adapts. If you never practise eating at effort, taking in 80 grams an hour on race day will leave you nauseous and bloated. If you rehearse it on your long training days, your gut learns to absorb more, comfortably. Treat high-rate fueling as a skill to build over weeks, starting modestly and working up, exactly as you would build any other capacity.

Rehearse race-day fueling in training, too. The long ride or run is the place to find out which products sit well, how much you can handle, and what your stomach refuses. Nothing new on the day.

Train Fondo builds in-session fueling into your long and hard sessions, telling you roughly how many grams per hour to target for that specific effort, and it ramps the amount progressively so your gut is trained to handle race-day intake rather than meeting it cold. The fueling plan lines up with the day's demand instead of being an afterthought you improvise at the roadside.