Marathon Fueling Strategy That Got Me Under 3 Hours
I ran 2:54:12 at the Rotterdam Marathon this spring. That time was the product of 16 weeks of structured training, but it was also the product of getting my fueling right after getting it catastrophically wrong. Two years ago, at the same race, I hit the wall at kilometer 35 and crawled home in 3:14. Same fitness. Same legs. Completely different fueling strategy.
The difference between those two races was not talent or training volume. It was carbohydrates. Specifically, how many grams per hour I consumed, when I started consuming them, and how I had trained my gut to handle the load.
This article is my complete fueling protocol. Not theory. Not general guidelines. The exact products, exact timing, and exact amounts that carried me to a 2:54 finish.
The Lesson From Bonking
Let me start with what went wrong in 2024. My old strategy was simple: one gel every 5km starting at km 10. That gave me roughly 25g of carbs every 25 minutes, or about 60g per hour. For years, that was the standard recommendation. It is also inadequate for a sub-3 attempt.
At km 35, my pace dropped from 4:05/km to 4:45/km in the space of two kilometers. My legs felt hollow. My brain went fuzzy. I knew exactly what was happening because I had read about glycogen depletion, but experiencing it at race pace is something else entirely. You do not slow down by choice. Your body simply refuses to maintain the effort.
That experience sent me down a research rabbit hole. The newer sports science is clear: trained athletes can absorb and oxidize 90-120g of carbohydrates per hour when using a glucose-fructose blend, provided they train their gut for it. Sixty grams per hour is leaving performance on the table.
The Protocol That Worked
Here is my race day fueling plan, broken into three phases: pre-race, early race, and mid-to-late race.
Pre-Race (3 Hours Before Start)
I wake up at 5:30am for a 9:00am start. Breakfast is a large bowl of white rice with honey and a banana. Total: approximately 120g of carbohydrates. White rice because it is easy to digest and does not cause GI distress. I avoid fiber, fat, and excessive protein in this meal.
At 7:30am (90 minutes before start), I drink 500ml of water with a Precision Hydration 1500 tab. This front-loads sodium, which helps with fluid retention during the race.
At 8:30am (30 minutes before start), I take one Maurten Gel 100. This is my insurance policy. It tops off liver glycogen without spiking insulin because I am already warmed up and moving by this point.
Early Race (Km 0-15)
I take my first in-race gel at km 5. Not km 10, not km 8. Km 5. This is earlier than most runners fuel, and people look at me strangely at aid stations. But the science is clear: starting fueling early means your glycogen stores deplete slower because you are supplementing exogenous carbs from the beginning.
From km 5 onward, I take one Maurten Gel 100 every 20 minutes. Each gel delivers 25g of carbs (glucose-fructose 0.8:1 ratio). At my race pace of 4:06/km, 20 minutes covers roughly 4.8km.
Mid-to-Late Race (Km 15-42.2)
The protocol does not change. One gel every 20 minutes. The consistency is the point. I do not wait until I feel depleted. I do not skip a gel because my stomach feels full. The schedule is the schedule.
At every major aid station (approximately every 5km), I grab water and take a few sips to wash down the gel. I alternate between water and the on-course electrolyte drink.
Here is the complete timing breakdown:
| Timing | What I Take | Carbs (g) | Notes |
|---|---|---|---|
| 3h before | Rice + honey + banana | 120 | Low fiber, easy digest |
| 90 min before | PH 1500 in 500ml water | 0 | Sodium preload |
| 30 min before | Maurten Gel 100 | 25 | Top-off gel |
| Km 5 (20 min) | Maurten Gel 100 | 25 | First race gel |
| Km 10 (40 min) | Maurten Gel 100 + water | 25 | Grab water at station |
| Km 14 (60 min) | Maurten Gel 100 | 25 | Hourly carbs: ~75g |
| Km 19 (80 min) | Maurten Gel 100 + electrolyte | 25 | Switch to e-lyte drink |
| Km 24 (100 min) | Maurten Gel 100 | 25 | Halfway point |
| Km 28 (115 min) | Maurten Gel 100 + water | 25 | Critical fueling zone |
| Km 33 (135 min) | Maurten Gel 100 | 25 | Where I bonked last time |
| Km 37 (150 min) | Maurten Gel 100 + water | 25 | Home stretch begins |
| Km 40 (163 min) | Optional last gel | 25 | Only if stomach allows |
Total in-race carbs: approximately 225-250g over 2 hours 54 minutes. That works out to roughly 80-85g per hour. Combined with the pre-race loading, my total carbohydrate intake from 3 hours before start through the finish line is around 370-395g.
Why Maurten Specifically
I have tested multiple gel brands during training. You can read my full comparison in Maurten vs SiS vs Spring Energy, but the short answer is that Maurten uses a hydrogel technology that encapsulates the carbohydrates, reducing osmolality in the stomach. In practical terms: less sloshing, less nausea, fewer GI issues at high intake rates.
I tried SiS Isotonic gels (which are also easy on the stomach) but found the volume per gel too large. At 8-9 gels per race, the liquid volume adds up. Maurten is more concentrated.
I tried Spring Energy (real food-based gels) and liked the taste but found them harder to consume at pace because of the thicker consistency.
For a broader overview of gel options, check out best running gels for 2026.
Training Your Gut
This is the piece most runners skip, and it is arguably the most important part. You cannot show up on race day and suddenly consume 80g of carbs per hour if your gut has never handled that load before.
Starting 12 weeks before my target race, I practiced race fueling on every long run. Initially, my stomach protested. I felt bloated after three gels. By week 8, I could handle four gels per hour without any issues. By race day, the protocol felt automatic.
My gut training progression:
- Weeks 12-10: One gel every 30 minutes on long runs (50g carbs/hour)
- Weeks 9-7: One gel every 25 minutes (60g carbs/hour)
- Weeks 6-4: One gel every 20 minutes (75g carbs/hour)
- Weeks 3-1: Full race protocol on the final long runs
This gradual increase lets your intestinal transporters upregulate. The SGLT1 (glucose) and GLUT5 (fructose) transporters in your small intestine become more efficient at absorbing carbohydrates when consistently challenged. This is not bro science. It is well-documented in sports physiology literature.
Electrolyte Strategy
Sodium loss is the other piece of the puzzle. At my sweat rate (approximately 1.2 liters per hour in moderate conditions), I lose roughly 900-1100mg of sodium per hour. Under-replacing sodium leads to hyponatremia risk, but practically, it also impairs fluid absorption and can contribute to cramping.
My protocol: Precision Hydration 1500 before the race (1500mg sodium per liter), then I rely on the on-course electrolyte drinks plus the sodium content in Maurten gels (about 35mg per gel). This is not perfect, but it worked in Rotterdam where conditions were 12 degrees and overcast.
For hot races, I would increase the pre-race sodium load and consider carrying salt capsules. Check the full hydration strategy for marathons for more detail.
The Carb Loading Phase
Race day fueling starts three days before the gun goes off. From Wednesday through Friday before a Sunday marathon, I increase carbohydrate intake to 10-12g per kilogram of body weight. At 68kg, that means 680-816g of carbs per day for three days.
This is an absurd amount of food. I eat white rice, pasta, bread, potatoes, fruit juice, and jam. I reduce fiber and fat to make room. The goal is to maximize muscle glycogen storage, which gives you approximately 2,000 calories of readily available energy on race day.
I wrote a detailed breakdown of my carb loading approach in the complete carb loading strategy.
Common Mistakes I See
Starting fueling too late. If you wait until km 15 or 20 to take your first gel, you have already depleted significant glycogen. Start early, stay consistent.
Under-fueling total carbs. Sixty grams per hour was the old standard. For sub-3 efforts, aim for 80-90g per hour if your gut can handle it.
Not practicing in training. Race day is not the time to discover that a particular gel brand causes stomach cramps at pace.
Relying solely on on-course nutrition. You cannot control what is offered at aid stations. Carry your own gels. I tape them to my race belt in the order I will use them.
Drinking too much plain water. Water without electrolytes dilutes sodium concentration. Use electrolyte drinks at aid stations when available.
Carrying Gels During the Race
I carry 6 gels taped to a thin race belt (FlipBelt). They are arranged in order of consumption. I take the remaining 3-4 from aid station tables (Rotterdam provides Maurten at selected stations, which I confirmed beforehand). If your race does not offer your preferred gel, carry them all. Nine Maurten gels weigh about 270g total. That is negligible weight.
Race Morning Timeline
- 5:30am: Wake up, breakfast immediately
- 6:00am: Finish eating, begin hydration
- 7:30am: PH 1500 tablet in water
- 8:00am: Leave for start area
- 8:30am: Pre-race gel
- 8:45am: Final bathroom stop
- 9:00am: Race start
This timing gives me exactly 3 hours of digestion for breakfast and 30 minutes for the pre-race gel. I have tested this timeline on at least 8 long runs. Do not deviate on race day.
FAQ
How do you avoid GI distress taking that many gels?
Gut training over 12 weeks is the answer. You progressively increase the carbohydrate load during long runs until your digestive system adapts. I also avoid high-fiber and high-fat foods for 24 hours before a race or long run. Maurten’s hydrogel formulation helps too because it reduces stomach acidity compared to traditional gels.
What if the race does not offer your preferred gel brand?
Carry everything yourself. I have run races where I carried all 9 gels on my belt. It adds minimal weight and removes all uncertainty. Never rely on race-provided nutrition unless you have tested that exact product in training.
Is 90g of carbs per hour safe?
For a trained gut using a glucose-fructose blend, yes. The dual-transport mechanism allows absorption beyond the old 60g/hour limit. However, you must build up gradually. Jumping straight to 90g without gut training will cause serious GI distress.
Do you use any solid food during the marathon?
No. At 4:06/km pace, chewing and digesting solid food is problematic. Gels are the most efficient delivery mechanism at race intensity. Some ultramarathon runners use solid food at lower intensities, but for a sub-3 marathon, gels are the way.
What would you change for a hot weather marathon?
I would increase pre-race sodium loading (PH 1500 doubled to two servings), add electrolyte capsules every 45 minutes during the race, reduce pace expectations slightly, and accept that GI absorption may be reduced due to blood flow being diverted to skin for cooling. Hot weather marathons require a more conservative early pace and even earlier fueling.
The Bottom Line
My 2:54 was not a breakthrough in fitness. It was a breakthrough in fueling. The training was essentially the same as my 3:14 performance two years earlier. The difference was going from 60g carbs/hour to 80g+, starting at km 5 instead of km 10, and spending 12 weeks training my gut to handle the load.
If you are chasing a sub-3 or any significant marathon PR, do not overlook nutrition. It is the cheapest, most accessible performance gain available to you.