Endurance fueling has turned into a bit of an arms race.

90 grams of carbohydrate per hour became 100. Then 120. And along with that came the idea that a 1:1 glucose-to-fructose ratio is somehow the new standard and that 2:1 is outdated.

The research doesn't really say that.

Two studies, two different outcomes

A 2022 study by Podlogar and colleagues compared trained cyclists consuming either:

• 90g/hr at a 2:1 glucose-to-fructose ratio
• 120g/hr at a ratio closer to 1:1

At 90g/hr, about 86% of the carbohydrate consumed was oxidized during the final hour.

At 120g/hr, that number dropped to about 76%.

The 120g group still oxidized more carbohydrate-roughly 91g versus 77g per hour, but the additional 30g consumed produced diminishing returns.

More importantly, the extra carbohydrate did not further reduce the athletes' use of their own stored carbohydrate.

The authors concluded that, from a whole-body metabolic standpoint, going above 90g/hr provided no additional benefit in that experiment.

Then came a 2025 study by Ravikanti and colleagues.

Elite male marathoners-average personal best around 2:23-ran for two hours while consuming:

• 60g/hr glucose
• 90g/hr at 2:1
• 120g/hr at 1:1

This time, carbohydrate oxidation continued to rise at 120g/hr, and the researchers also measured a lower oxygen cost of running under the highest-carb condition.

So does that prove 120g/hr and 1:1 are better?

Not quite.

Higher oxidation doesn't automatically mean better performance

Neither study actually tested whether athletes performed better at 120g/hr than at 90g/hr.

That matters. A lot.

A metabolic measurement tells us how much carbohydrate is being oxidized. It doesn't tell us whether an athlete goes faster, produces more power, or finishes a race sooner.

The authors of the 2025 study themselves noted that the performance implications of 120g/hr still need to be determined.

And in 2026, researchers Podlogar and Rowlands published a critique arguing that the apparent advantage of 120g/hr - particularly versus 90g/hr - should be interpreted cautiously.

So the interesting question isn't:

Can some athletes oxidize 120g/hr?

Clearly, they can.

The better question is:

Does everyone need to?

Right now, the evidence doesn't say yes.

And neither study proves 1:1 is better than 2:1

This is an important detail that gets lost in the social media version of the debate.

In both studies, carbohydrate dose and carbohydrate ratio changed at the same time.

The researchers didn't give one group 90g/hr at 2:1 and another 90g/hr at 1:1 and ask which worked better.

So these studies cannot tell us that 1:1 is inherently superior to 2:1.

What they suggest is something more nuanced:

At very high carbohydrate intakes-particularly around 100-120g/hr-moving toward a more balanced glucose-to-fructose ratio may make sense.

That does not mean a 2:1 ratio suddenly stops working at 80-90g/hr.

Your gut still gets a vote

There's another variable that matters enormously: what you can actually tolerate.

Repeated high-carb feeding during training can improve an athlete's ability to handle larger carbohydrate loads. This is usually referred to as gut training.

That may be one piece of the puzzle behind why some athletes handle 100-120g/hr extremely well while others end up bloated, nauseated or cramping.

The 2025 marathon study is instructive here.

Even in elite runners, gastrointestinal symptoms - including nausea, fullness and abdominal cramping - were greatest at 120g/hr.

That's not an argument against 120g/hr.

It's an argument against assuming you can jump straight to it because you saw someone on Instagram doing it.

If you want to race on 120g/hr, you should probably train on 120g/hr.

Then there's the simplest question: will you actually drink it?

A fueling plan only works if you can execute it for hours.

Very high carbohydrate concentrations can become increasingly difficult to drink as fatigue, heat, intensity and flavor fatigue pile up.

And fructose is sweeter than glucose, so palatability can become another practical constraint as fructose content increases - although the actual experience depends heavily on formulation, concentration and the individual athlete.

The perfect carbohydrate ratio on paper doesn't help much if half the bottle comes home with you.

Fuel you consistently consume beats theoretically perfect fuel you don't.

Why 333 still uses 2:1

This is where our philosophy with 333 Half Evil comes in.

333 delivers 84g of carbohydrate per serving using a 2:1 glucose-to-fructose ratio.

That's already a high carbohydrate intake using multiple transportable carbohydrates.

We're not claiming 1:1 is bad.

We're not claiming 120g/hr can't work.

And we're definitely not claiming 2:1 is magically superior at every carbohydrate dose.

We're saying something much simpler:

There isn't convincing evidence that every endurance athlete needs to abandon 2:1, jump to 1:1 and start forcing down 120g of carbohydrate every hour.

If you've deliberately trained your gut, tolerate 100-120g/hr well, and perform better using it, that's a completely legitimate strategy.

But if you're fueling around 80-90g/hr, a 2:1 glucose-to-fructose ratio remains a rational, research supported way to deliver a large amount of carbohydrate without automatically chasing the highest possible number.

One clarification: 84g is a serving size, not a ceiling. It's a 2:1 ratio, not a fixed dose.

That's why 333 sits where it does.

84g. 2:1. Simple enough to use. High enough to fuel serious endurance. Easy to scale up once you've trained it.

Because more isn't automatically better.

Absorbable, tolerable and repeatable is better.

Brad K.

Sources

Podlogar T, Bokal Š, Cirnski S, Wallis GA. Increased exogenous but unaltered endogenous carbohydrate oxidation with combined fructose-maltodextrin ingested at 120 g·h⁻¹ versus 90 g·h⁻¹ at different ratios. Eur J Appl Physiol.2022;122(11)

Ravikanti S, et al. 13C-labelled glucose-fructose show greater exogenous and whole-body carbohydrate oxidation and lower O2 cost of running at 120 versus 60 and 90 g/h in elite male marathoners. J Appl Physiol. 2025 (epub ahead of print).

Podlogar T, Rowlands DS. Does 120 g/h carbohydrate ingestion really confer a metabolic advantage in elite marathoners? Methodological concerns and alternative interpretations. J Appl Physiol (1985). 2026;140(6):1802-1803.

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