The 120g/hr Carb Revolution: How Pros Fuel and How You Can Too

A decade ago, 60 grams of carbohydrate per hour was the textbook ceiling for endurance fueling. Today, WorldTour riders routinely consume 100–120 grams per hour during grand tour stages — and the science says you can too, if you train your gut for it.

The 2025 Sports Medicine narrative review on in-competition carbohydrate intake documented this revolution in detail. Teams like Visma-Lease a Bike, UAE Team Emirates, and Lidl-Trek now build fueling strategies around targets that would have seemed reckless just five years ago.

This is not a marginal gain. Researchers estimate that optimal high-carbohydrate fueling can improve endurance performance by 5–8% compared to traditional 60g/hr strategies — the difference between finishing mid-pack and riding onto the podium.

The Science: Why 60g/hr Was the Old Ceiling

The 60g/hr limit was not arbitrary. It reflected the saturation point of a single intestinal transporter called SGLT1, which absorbs glucose and maltodextrin in the small intestine. Once SGLT1 maxes out at approximately 60 grams per hour, additional glucose sits unabsorbed in the gut, draws water into the intestinal lumen via osmosis, and causes bloating, cramping, and diarrhea.

For decades, sports nutrition science stopped here. If your body can only absorb 60g/hr of glucose, consuming more is not just wasteful — it is actively harmful.

The breakthrough came from Asker Jeukendrup's research group, which demonstrated that fructose uses an entirely separate transporter called GLUT5. Because GLUT5 operates independently of SGLT1, adding fructose on top of glucose opens a second absorption channel capable of delivering an additional 30–60 grams per hour.

The Optimal Ratio: Glucose to Fructose

Early research used a 2:1 glucose-to-fructose ratio, which pushed total oxidation rates to approximately 90g/hr. More recent work from Jeukendrup's group and independent labs has refined this to a 1:0.8 ratio (roughly 1:1), which maximizes absorption from both transporters simultaneously.

At the 1:0.8 ratio, combined exogenous carbohydrate oxidation rates of 1.5–1.8 g/min (90–108 g/hr) have been consistently measured in laboratory settings. Individual variation exists — some athletes reach 120g/hr, others plateau closer to 90g/hr — but the dual-transport approach consistently outperforms glucose-only strategies by 40–65%.

Practically, this means your drink mix, gels, or bars need to contain both maltodextrin (or glucose) and fructose. Products with a single sugar source cap you at the old 60g/hr ceiling no matter how much you consume.

Reading Labels

Check the ingredients list, not just the nutrition facts panel. Look for products that list maltodextrin (or glucose, dextrose, glucose syrup) alongside fructose. Sucrose (table sugar) naturally contains a 1:1 glucose-to-fructose ratio and is a surprisingly effective fuel source — many commercial products now use it for exactly this reason.

Avoid products that list only maltodextrin or only glucose. These are SGLT1-only fuels that will not support intakes above 60g/hr without GI distress.

What the Pros Actually Consume

WorldTour team nutritionists have shared remarkable detail about stage-day fueling plans. A typical 4–5 hour grand tour stage now involves:

These numbers sound staggering, but they are backed by physiological demand. A pro rider burning 800–1,000 kcal per hour for five hours needs every gram. The riders who bonk in week three of the Tour are almost always the ones whose fueling broke down, not the ones whose legs gave out.

When You Actually Need 120g/hr (and When You Do Not)

Not every ride warrants aggressive fueling. The 120g/hr target is for specific situations, and applying it to every ride is both unnecessary and uncomfortable.

Intensity matters too. At zone 2 pace, fat oxidation covers a larger proportion of energy demand, so carbohydrate needs are lower. Above 75% of FTP, carbohydrate becomes the dominant fuel and aggressive intake becomes essential to sustain performance.

The 8-Week Gut Training Protocol

You cannot jump from 40g/hr to 120g/hr overnight. Your intestinal transporters need progressive overload, just like your muscles. Research from the University of Birmingham showed that two weeks of high-carbohydrate feeding during exercise significantly upregulated SGLT1 expression and improved gut comfort at higher intakes.

The protocol below is conservative and works for the vast majority of riders. It assumes you start from a baseline of minimal or no deliberate on-bike fueling.

Some important nuances: practice at the intensity you expect to race at. Gut tolerance at zone 2 is much higher than at threshold. A fueling rate that feels fine during an easy endurance ride may cause problems when you push the pace.

Also increase daily carbohydrate intake on training days. Research suggests that high-carbohydrate diets (8–10 g/kg/day) upregulate intestinal transporters even when consumed as meals, not just during exercise.

DIY Drink Mix: The Budget Option

Commercial high-carb drink mixes cost $2–4 per serving. You can make your own for roughly $0.30 per bottle with three ingredients from any grocery store.

The taste will not match commercial products, but the physiology is identical. Adding a small amount of sugar-free drink flavoring (like Mio or Crystal Light) makes it significantly more palatable. A squeeze of lemon or lime juice works too.

If DIY mixing is not your thing, table sugar (sucrose) dissolved in water with a pinch of salt is a perfectly acceptable alternative. Sucrose is 50% glucose and 50% fructose — a near-optimal ratio. Eighty grams of sugar in 500ml of water with a quarter teaspoon of salt costs essentially nothing.

Commercial Products Compared

If you prefer the convenience and consistency of commercial products, here is how the major options stack up for high-carb fueling.

The most efficient approach for high-rate fueling: use a concentrated drink mix as your base (60–80g per bottle) and supplement with gels every 20–30 minutes. This delivers carbs and hydration simultaneously without requiring you to unwrap anything at high intensity.

Common Mistakes When Going High-Carb

The shift to high-carb fueling is straightforward in theory but easy to botch in practice. These are the mistakes that send riders to the bushes at the side of the road.

Skipping Gut Training

This is the number one failure mode. Your gut is not ready to absorb 120g/hr just because you bought the right products. The intestinal transporters need weeks of progressive overload. Jumping straight to race-rate fueling in a sportive you have not trained for is a near-guaranteed GI disaster.

Wrong Sugar Type

Consuming 120g/hr of glucose-only products means 60g sits unabsorbed in your gut. Always use dual-transport sources. Check the label.

Ignoring Concentration

Drink mixes above 8–10% carbohydrate concentration (80–100g in a 1-liter bottle) can slow gastric emptying. In concentrated bottles (say, 80g in 500ml, which is 16%), carry a second bottle of plain water or electrolyte solution to sip alongside. Alternating concentrated and dilute bottles maintains hydration while keeping carb delivery high.

Forgetting Sodium

Sodium is a co-transporter with glucose via SGLT1. Without adequate sodium, glucose absorption is impaired. 500–1,000 mg of sodium per hour supports both hydration and carbohydrate uptake. Most drink mixes include sodium, but check the amount. Many are underdosed.

All-or-Nothing Thinking

You do not need to hit 120g/hr on every long ride. Even increasing from 40g/hr to 70g/hr is a massive performance upgrade for most amateur cyclists. Start where you are, improve progressively, and find the intake rate your body handles well.

The Evidence: Does It Actually Work?

The 2025 Sports Medicine review aggregated data from 61 studies on carbohydrate intake during endurance exercise. The findings are unambiguous.

Dual-transport carbohydrate at rates of 90–120g/hr improved time trial performance by 5–8% compared to placebo and by 2–4% compared to lower carbohydrate intakes (less than 60g/hr). The benefits were most pronounced in events lasting longer than 2.5 hours.

Gut symptoms were reported less frequently with trained guts consuming dual-transport carbohydrate than with untrained guts consuming glucose-only at lower rates. The dual-transport mechanism actually reduces GI distress at higher intakes because less unabsorbed sugar remains in the intestinal lumen.

Perhaps most importantly for amateur cyclists: the performance benefits were not limited to elite athletes. Recreational riders showed similar relative improvements when fueling adequately.

Putting It All Together

The 120g/hr carb revolution is not hype. It is supported by decades of transport physiology research, confirmed by real-world WorldTour results, and accessible to any amateur willing to invest eight weeks of gut training.

Start at 40g/hr. Increase by 10g/hr every one to two weeks. Use dual-transport products with both glucose (or maltodextrin) and fructose. Add sodium. Set a timer every 20 minutes and eat on schedule. Practice at race intensity. Never try anything new on event day.

The best fueling strategy is the one you have practiced until it is automatic. By the time you line up for your target event, eating and drinking should be as natural as pedaling — something your body does without conscious effort, freeing your mind to focus on the race.