Marathon Fueling Plan by Finish Time: 3:00, 3:30, 4:00, 4:30, and 5:00

A marathon fueled at 75-90g of carbs per hour comes out to 225g of total carbs for a 3:00 finish and 450g for a 5:00 finish. In gels, that spread is 6 to 18 packets: 6 or 7 for a three-hour runner on 40g gels, 15 to 18 for a five-hour runner on 25g gels. The rate stays flat across all five finish times. Only the duration changes.

That last point is the one most runners get wrong. Your gut absorbs carbohydrate at roughly the same rate whether you are running 6:52 pace or 11:27 pace, so a 5:00 marathoner does not need a lower hourly target than a 3:00 marathoner. They need almost double the total fuel, carried and consumed over two extra hours, in warmer conditions, with more chances to fall behind.

Below are five plans with the arithmetic shown, built around two representative gels: Maurten Gel 100 at 25g, which stands in for GU Roctane, Tailwind, and most standard packets, and SiS Beta Fuel at 40g, which stands in for Maurten Gel 160 and the rest of the high-density class.

Why the target is 75-90g/hr and not 30-60g/hr

The 30-60g/hr number still printed on the back of gel packets comes from research on glucose alone. Glucose crosses the intestinal wall through the SGLT1 transporter, and SGLT1 saturates at roughly 60g/hr. That was a real ceiling, and for a single-source carb it still is.

Asker Jeukendrup’s work on multiple transportable carbohydrates broke it. Fructose uses a separate transporter, GLUT5, so a glucose and fructose blend recruits two absorption pathways instead of one and pushes measured exogenous carbohydrate oxidation past 90g/hr. Every gel in this article is dual-source: SiS Beta Fuel runs 1:0.8 maltodextrin to fructose, Maurten runs 0.8:1 fructose to glucose, GU runs roughly 2:1.

David and Megan Roche’s fueling framework, which is what the FuelCenter calculator is built on, puts 75-90g/hr as the baseline for moderate-to-hard efforts over 90 minutes, with 105-120g/hr available to athletes who have trained their gut for it. Treat 75g/hr as the floor of a marathon plan, not the target.

3:00 marathon fueling plan

Three hours at 6:52 pace. 225g of carbs at 75g/hr, 270g at 90g/hr. That is 9-11 Maurten Gel 100s, or 6-7 SiS Beta Fuels.

On 40g gels: six gels, one every 25 minutes, starting at minute 20. That is 240g total, or 80g/hr. Miles 3, 6.5, 10, 14, 17.5, and 21. The last one goes down 35 minutes before you finish, which is exactly where you want it. A seventh gel at minute 170 would get you to 93g/hr but lands with 10 minutes left, too late to matter.

On 25g gels: ten gels every 15 minutes from minute 20, which is 250g and 83g/hr. Roughly every 2.2 miles, last one just past mile 22. A 20-minute cadence on a 25g gel only produces 75g/hr, and the fueling window runs out before you get to 90.

The 3:00 plan is the easiest of the five to execute. You are on course for the shortest time, you need the least total volume, and the effort is high enough that skipping a gel shows up fast enough to notice.

3:30 marathon fueling plan

Three and a half hours at 8:01 pace. 263g at 75g/hr, 315g at 90g/hr. That is 11-13 Maurten Gel 100s, or 7-8 SiS Beta Fuels.

On 40g gels: seven gels, one every 25 minutes, first at minute 25. Miles 3, 6, 9.5, 12.5, 15.5, 19, and 22. Seven times 40 is 280g, which is 80g/hr over 3.5 hours. To reach 315g you need an eighth gel, and at a 25-minute cadence it falls at minute 200, past mile 24. Tighten to a 22-minute cadence instead, or cover the last 35g with drink mix.

On 25g gels: eleven gels every 15 minutes from minute 20, ending at minute 170 near mile 21. That is 275g, or 79g/hr, one gel every 1.9 miles. A twelfth at minute 185 puts you at 300g and 86g/hr, and mile 23 is still early enough to absorb it.

4:00 marathon fueling plan

Four hours at 9:10 pace. 300g at 75g/hr, 360g at 90g/hr. That is 12-15 Maurten Gel 100s, or 8-9 SiS Beta Fuels.

On 40g gels: eight gels every 25 minutes from minute 25. Miles 2.5, 5.5, 8, 11, 13.5, 16, 19, and 22. That is 320g and 80g/hr, with the last gel 40 minutes out. A ninth gel gets you to 360g and a true 90g/hr, but only if you move to a 22-minute cadence so it lands before mile 22 instead of after mile 24.

On 25g gels: twelve gels every 17-18 minutes from minute 20, which works out to one roughly every two miles and ends near mile 22.5. Twelve times 25 is 300g, an exact 75g/hr. Getting to 360g means 15 packets on a 13-minute cadence, which nobody executes cleanly. Add drink mix instead.

Four hours is where the gel-count problem starts to bite. Twelve packets is a lot of wrapper handling, and it is the point at which switching to a 40g gel or moving 30g/hr into fluid stops being a preference and starts being the plan.

4:30 marathon fueling plan

Four and a half hours at 10:18 pace. 338g at 75g/hr, 405g at 90g/hr. That is 14-17 Maurten Gel 100s, or 9-10 SiS Beta Fuels.

On 40g gels: nine gels every 27 minutes from minute 25. Miles 2.5, 5, 7.5, 10.5, 13, 15.5, 18, 21, and 23.5. That is 360g, or 80g/hr, and the last one still has 29 minutes of running left to work with. A tenth gel gets you to 400g and 89g/hr if your stomach is still cooperating at that point.

On 25g gels: fourteen gels every 17 minutes, roughly one every 1.65 miles, for 350g and 78g/hr. Fourteen packets is the argument against 25g gels at this distance. It is a lot of volume, a lot of pockets, and a lot of chances to miss one.

Two things change for real at 4:30 and beyond. You are on course through more of the day, so a race that starts at 7:00 AM finishes near noon and the last 90 minutes are meaningfully hotter than the first. Heat pulls blood toward the skin and away from the gut, which is exactly when absorption gets harder. Front-load: bank carbs in the first two hours while your stomach is fresh and the temperature is still reasonable, so a missed gel at mile 22 is a rounding error instead of a bonk.

Second, if you have not actually trained your gut, do not force 90. Executing 65-75g/hr cleanly beats attempting 90g/hr and losing it at mile 18. That is a temporary floor and a training problem, not a permanent target.

5:00 marathon fueling plan

Five hours at 11:27 pace. 375g at 75g/hr, 450g at 90g/hr. That is 15-18 Maurten Gel 100s, or 10-12 SiS Beta Fuels.

On 40g gels: ten gels every 27 minutes from minute 25. Miles 2, 4.5, 7, 9.5, 11.5, 14, 16.5, 18.5, 21, and 23.5. That is 400g and 80g/hr, with the last gel 32 minutes from the line. Eleven gels on a 24-minute cadence gets you to 440g and 88g/hr if your gut handles it, but ten gels plus 50g of drink mix is the more realistic route.

On 25g gels: fifteen gels every 17 minutes from minute 25, for 375g and a clean 75g/hr. Fifteen packets over five hours is a logistics problem more than a physiology problem, and most runners solve it by moving a third of the target into fluid.

Five hours is the case where the standard advice breaks down. You need the most total fuel, you get the most heat exposure, and your stomach has the longest window in which to revolt. Take the first gel at minute 25 even though it feels absurdly early at 11:27 pace, and hold the cadence through the first half when it feels unnecessary. Everything you bank before mile 13 is what you race the last 10K on.

All five plans side by side

25g class: Maurten Gel 100, GU Roctane, one scoop of Tailwind. 40g class: SiS Beta Fuel, Maurten Gel 160. Gel counts are the range from 75g/hr to 90g/hr, rounded up.

How to adjust the plan

Three variables move these numbers: what you drink, how hot it is, and what your gut has actually practiced.

Drink mix. Fluid carbs are the cleanest way to cut your gel count, and above four hours they are close to mandatory. Gatorade Endurance, the on-course drink at most American majors, carries 22g of carbs and 310mg of sodium per 12oz, so a partly filled 5oz aid station cup gives you about 9g. Two cups at each of three stations in an hour is roughly 25g/hr, and it is unreliable because cup fill varies. Carrying your own is better: Maurten Drink Mix 160 is 40g per 500ml bottle, and Tailwind runs 25g per scoop. Covering 30g/hr from fluid drops a 4:00 plan from 12 gels to 8, and a 5:00 plan from 15 to 9.

Heat. Warm conditions push blood toward the skin for cooling and away from the gut, which slows absorption at exactly the moment your fluid needs go up. The move is not to fuel less. It is to shift more of the target into dilute fluid, take gels with more water than usual, and get more of your total in during the first half. Run your goal time through the heat adjustment calculator first, because a slower finish time is a bigger total carb number, and see running in the heat for the pacing side.

Gut training. Carbohydrate absorption is trainable. Repeated exposure to high carb intake during hard efforts upregulates intestinal transporter activity and reduces GI symptoms at a given intake, which is the finding behind the gut training work published over the last few years. In practice it means taking your race-day carb target on your race-day gel during long runs, not on water and a single gel at mile 14.

Six to eight weeks is enough to move most runners from 60g/hr to 75-90g/hr. Start at whatever you handle now, add 10g/hr every couple of weeks, and do it on the long runs that most closely match race effort. The full protocol is in how to practice race fueling on long runs.

Race day is not the day to find out what your stomach will take.

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