120 Grams of Carbs Per Hour: How Modern Pros Refuel — and Why You Should Too

A decade ago, the standard advice was 60 grams of carbohydrate per hour on the bike. Two decades ago, it was 30. Today, the pros at the Giro are knocking back 120 grams per hour — and according to recent research, that's not just a Pog-and-Vingegaard luxury. It's increasingly accessible to motivated amateurs willing to gut-train into it.

The dual-pathway breakthrough

The physiology hinges on a single fact: glucose and fructose are absorbed via different intestinal transporters. Glucose uses SGLT1, which saturates at about 60g/hour. Fructose uses GLUT5, which adds another 30-60g/hour on top. Combine the two — typically in a 2:1 or 1:0.8 glucose-to-fructose ratio — and you can comfortably absorb 90-120g/hour without the gut bloat and GI distress that doomed earlier high-carb attempts.

A 2026 review in the *Journal of the International Society of Sports Nutrition* tracked elite cyclists fueling at 120g/hour across Tour de France stages and found no significant GI complaints when the carb mix used the dual-pathway ratio AND athletes had gut-trained for at least 4-6 weeks prior. Without gut training, the same protocol caused diarrhea or vomiting in 40% of athletes by Stage 4. With gut training, that number dropped to under 5%.

What 120g/hour actually looks like

Translating that abstract number into actual food on the bike is the hard part. Here's the math: a typical sports drink mix gives you 60-80g of carbs per 750ml bottle, depending on concentration. A standard cycling gel is 25-30g. An energy bar is 30-45g.

So 120g/hour might look like: - 1 bottle of high-concentration mix (80g) + 2 gels (50g) = 130g/hour - 1 bottle of standard mix (60g) + 1 gel (25g) + half a bar (20g) + a banana mid-set = ~125g/hour - 2 bottles of moderate mix (60g each) + 1 gel = 145g/hour (overkill but works on a 5+ hour ride)

The pros tend to use either a single high-carb mix bottle (like Maurten 320 or SiS Beta Fuel) supplemented with gels, or a rotation of bottles with different ratios swapped at feed zones. The choice depends on race format. Stage racers often prefer the rotation; one-day racers and time trialists tend to go with the simpler single-mix approach.

Gut training: the part you can't skip

The biggest mistake amateurs make is jumping straight from 60g/hour to 120g/hour and assuming their stomach will keep up. It won't. The intestinal transporters that absorb fructose can be upregulated through consistent exposure, but it takes weeks.

A reasonable 6-week protocol:

• Weeks 1-2: Practice 60g/hour on every ride over 90 minutes. Use the 2:1 glucose-fructose ratio.
• Weeks 3-4: Bump to 80g/hour on long rides. Note any GI response — bloating, urgency, cramps. Back off if symptoms appear.
• Weeks 5-6: Push to 100-110g/hour on your longest rides. By the end of week 6, most cyclists can tolerate 120g/hour for 2-3 hour blocks.
• Race week: Practice fueling at race pace at race intensity. Don't introduce new products on race day.

Hydration matters here too. Concentrated carb solutions need adequate fluid to absorb properly — pair every bottle of fuel with a separate water bottle to manage osmolality.

When less is more

Not every ride needs 120g/hour. The fueling rate should scale with effort and duration:

• Under 90 minutes: Skip the fueling entirely or use water. Your glycogen stores are sufficient.
• 90 min - 2 hours: 30-45g/hour, especially if intensity is high.
• 2-4 hours: 60-90g/hour, depending on terrain and effort.
• 4+ hours or race intensity: 90-120g/hour, with the upper end reserved for hard race efforts.

For most enthusiast cyclists, 60-80g/hour is the sweet spot — meaningful enough to prevent the late-ride bonk, not so much that you're managing GI risk for diminishing returns. The 120g/hour number is for racers and ultradistance riders specifically targeting maximum sustained output.

What this means for your training

If you've been religiously fueling at 60g/hour because that's what your coach told you in 2018, the science has moved on. Bumping intake to 80-100g/hour on long endurance days will improve your back-half ride quality and probably your week-over-week training consistency.

The bigger insight from recent research, though, is that early fueling beats late fueling. Don't wait until you're hungry to eat. Start drinking your mix in the first 15-20 minutes of any ride over 90 minutes. Your blood glucose stays stable, your hormone response stays balanced, and you arrive at the back half of the ride with full glycogen rather than chasing a deficit you can't catch.

The science is clear. The bottle is in your cage. The only question is whether you'll use it.