Holmer says 100g of carbs an hour rewrites durability

The fat burning advantage researchers found in unfueled riders vanished once intake hit 100 grams an hour, Holmer says.

Running Daily · October 17, 2026 · How they train

Brady Holmer is making the case that high-carb fueling does not just add energy, it changes what durability even depends on. Durability is the ability to hold power late in a long effort, after the early miles have already taken something out of you. Holmer's argument is that carbohydrate availability sits at the center of it.

The piece of evidence he points to comes from Gabriele Gallo, PhD, who posted about his group's 2024 study. That study found a positive relationship between fat oxidation (how much fat you burn for fuel) during early exercise and time to task failure at 90% of the first threshold. In plain terms, the better fat burners lasted longer. Gallo's framing of the question was direct.

Then comes the part Holmer highlights. Without carbohydrate intake, higher early fat oxidation was associated with greater durability. Feed the athlete 100 grams of carbs an hour and that relationship is not there anymore. Being a good fat burner stops predicting anything once the fuel is coming in from outside.

What it actually means

This is a mechanism argument, not a race result. Holmer says three recent studies approach the question from different directions and together bring some clarity to why he thinks high-carb fueling works. None of that is the same as fresh evidence that eating more carbs made anyone run a faster marathon. It is an explanation for why the fueling advice has moved the way it has, built out of studies that already exist.

It does line up with how Holmer has been talking about this all month. He has also argued that more carbs per hour does not guarantee a bigger payoff, so the takeaway here is not simply eat more forever. The claim is narrower and more interesting than that. If you are properly fueled, your metabolic profile matters less than it does when you are running on empty.

For anyone training for a fall marathon, the practical read is unchanged. Nothing here tells you a number to hit on race day. It tells you why the researchers keep finding that fueled athletes hold on better, and why the old obsession with teaching your body to burn fat looks less useful once the gels are flowing.