Grandma's Marathon Fueling Plan: Mile-by-Mile Strategy

Grandma's Marathon has a reputation as a fast, friendly course. And it earns it—net downhill, mostly flat, a prevailing tailwind off Lake Superior. But the same features that make it a BQ factory also create a fueling trap that catches runners every June.

The course runs 26.2 miles in a nearly straight line from Two Harbors to Duluth along Highway 61. There's almost no shade. The first aid station isn't until mile 3. And the defining feature—Lemon Drop Hill at mile 22—arrives exactly when your glycogen stores are running on fumes. In 2025, race organizers issued a red flag as temperatures climbed past 80°F and humidity hit the 90th percentile. Eight runners were hospitalized. The front-of-pack mostly dodged the worst of it. Mid-pack and back-of-pack runners got hammered.

The course will forgive pacing mistakes. It won't forgive fueling mistakes.

Miles 1-6: Two Harbors to Knife River

The start sits at 740 feet of elevation. You'll lose about 130 feet over the full course, and some of that comes early—a notable descent around mile 2 drops 35 feet in a third of a mile. The legs feel light. The air off the lake is cool. The temptation is to bank time.

Don't.

The first aid station is at mile 3, which means you're running nearly 25 minutes before you see water or Powerade. If it's a warm year, you need to start hydrated—pre-load fluids in the hour before the gun. Take your first gel at mile 3, right at that first aid station. Your stomach is fresh, the effort is easy, and you're setting the rhythm for the next three hours.

There's a short, steep climb at mile 5.4 (2.69% grade, about 30 feet of gain). It's nothing to worry about physically, but it's a useful marker: by the time you crest it, you should have one gel down and be thinking about your second.

Miles 7-13: North Shore coastline

This is the prettiest stretch and the most important for fueling. You're running along Lake Superior with water views to the east, the terrain is largely level with minor rollers, and the effort is moderate. Aid stations at miles 7, 9, 11, and 13 give you water every two miles.

This is where you build your carb bank.

Lock in your gel timing here—one every 20-30 minutes depending on your brand. The terrain isn't disrupting your stomach. The effort isn't spiking your heart rate. There's no reason not to eat. By mile 13 (McQuade Harbor, approaching halfway), you should have consumed 3-5 gels and be sitting on 150-200g of absorbed carbs.

Watch for crosswinds near McQuade Harbor around mile 13. The course is exposed here and a shift in wind direction can change the race. If the prevailing northeast wind holds, you have a tailwind all day—that's the Grandma's advantage. If it shifts southwest, every mile gets harder.

One thing this stretch doesn't have: crowds. The spectator support is sparse through here. If you're someone who relies on crowd energy to stay sharp, use your gel timer as your metronome instead.

Miles 13-19: The quiet stretch

This is the loneliest section of the race. Congdon Boulevard offers virtually no vertical variance and minimal crowd support. Your body feels fine. Your mind starts to wander. Pacing discipline and fueling discipline both get tested.

Maintain your protocol. Aid stations at miles 15, 17, and 19 keep you covered. Mile 17 is significant—this is where the course provides gels (Pure Fuel). If you've been carrying your own, this is a bonus. If you planned to rely on the course, this is your only gel station. Either way, take one here.

The longest continuous downhill starts around mile 18 at a gentle grade. Use the descent to settle into your rhythm. The Lester River aid station at mile 19 marks a turning point—fresh fruit, the first real crowd energy since Two Harbors, and a glimpse of Duluth proper.

Here's the key fueling moment: take a gel between miles 18-19, during the descent, before the terrain changes. The carbs from this gel will be absorbing through your system right when you need them most—during Lemon Drop Hill at mile 22. If you wait until mile 20 or 21, you're trying to fuel while your heart rate is climbing and crowds are pulling your attention. Get it done early, in the quiet, while the road is going your way.

Miles 19-22: London Road and Lemon Drop Hill

London Road is where Grandma's Marathon becomes a party. The Lakeside neighborhood turns out yard parties, music, unofficial aid stations with lemonade, fruit, and—if you're feeling reckless—bacon and beer. The energy shift from the quiet stretch is jarring in the best way.

Don't let it wreck your fueling plan.

Aid stations at miles 20, 21, and 22 stack up quickly. Grab water at each one. The crowd energy masks fatigue, and runners routinely push too hard through here, arriving at Lemon Drop Hill having spent energy they can't get back.

Lemon Drop Hill (mile 22)is the race's defining feature. It's roughly half a mile of sustained climbing with two distinct pitches—the first at a 4.66% grade (25 feet of gain in a tenth of a mile) and the second at 3.02%. Total gain: about 48 feet. On paper, that's nothing. At mile 22 of a marathon, it's everything.

Keep effort level steady. Do not attack this hill. The runners who try to power through Lemon Drop are the same ones walking at mile 24. Shorten your stride, maintain your breathing, and let the crowd carry you. There's an aid station at mile 22—grab water if you need it, but don't try to eat on the climb. Save your last gel for the other side.

Miles 23-26.2: Downtown Duluth to Canal Park

The course drops 28 feet across the final 4 miles, mostly flat with a few turns through downtown Duluth. Mile 23 has fresh fruit at the aid station. The Duluth Rose Garden at mile 23.4 and the Lake Superior Railroad Museum at mile 25 are landmarks that tell you the finish is close.

Take your final gel at mile 23 if your stomach allows it. That gives the carbs roughly 20 minutes to absorb before the finish.

Watch for the steepest descent of the entire course at mile 25.2—a 4.21% downhill grade over a tenth of a mile. Keep your stride quick and light. Your quads have been absorbing downhill impact for 25 miles, and this is where sloppy form creates the kind of muscle damage that turns the last mile into a shuffle.

The finish in Canal Park is one of the best in American marathoning. Heavy spectator support, a flat final 400 meters, and Grandma's Restaurant waiting at the end. If you fueled the quiet stretch and respected Lemon Drop Hill, you'll be racing this section, not surviving it.

Weather: plan for heat

Grandma's has a reputation as a cool-weather marathon, and in good years (2023: 63°F, 18.9% BQ rate) it lives up to it. But June in Duluth is not guaranteed to be kind. The 2025 race proved that.

Cool conditions (under 60°F):Ideal. Go aggressive on carbs—80-90g/hr or higher if you've trained for it. The science behind high-carb fueling works best when your core temperature is controlled.

Warm conditions (60-75°F):Increase fluid intake at every aid station. Shift more carbs to liquid form. The limited shade on Highway 61 means you're exposed for 20+ miles. Use the FuelCenter heat adjustment calculatorto dial in your pace adjustment—every degree above 60°F costs you.

Hot conditions (75°F+, like 2025):Protect yourself first, time goal second. Slow down 10-15 seconds per mile. Take water at every single aid station. If race organizers issue a yellow or red flag, respect it. No BQ is worth a 108°F core temperature.

Lake Superior is your ally regardless of conditions. The lake surface sits around 45°F in June and moderates air temperature along the entire course. Sections closer to the water will feel noticeably cooler than inland stretches. On warm days, this is the margin that keeps the race runnable.

Hydration on course

Grandma's has 15 aid stations. Every two miles for the first half (miles 3, 5, 7, 9, 11, 13, 15, 17), then every mile from 19 onward (miles 19, 20, 21, 22, 23, 24, 25). Water and Powerade Ion4 at every station. Gels (Pure Fuel) at mile 17 only. Fresh fruit at miles 19 and 23.5.

The back-loaded aid station spacing is smart: you need more support in the final miles, and the course delivers it. But the front-loaded gap is the risk. Nothing before mile 3 means you need to start hydrated. Carry a small handheld for the first 3 miles if the forecast is warm and you can't afford to wait.

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