How I fueled for my marathon without any GI issues and ran a PR (3:28!)

post featured image
The following content may contain affiliate links. When you click and shop the links, we receive a commission.

My marathon fueling strategy was well-tested in my training so I knew what worked for me — and what didn’t. Here’s what I ate before, during and after my last marathon, where I qualified for Boston and had no GI issues!

marathon fueling strategy

Fueling is HUGELY important for races, especially marathons. When I was leading up to the Wrightsville Beach Marathon, my fueling strategy was a week-long approach, not just the day of or even just the day before. I didn’t drastically change my eating before race or do anything to carb-load because when your mileage is reduced in the taper, glycogen (the fuel your muscles stores) won’t be depleted as much. So, you’re essentially carb-loading just by reducing your mileage. But the day before and the day of are especially important, so make sure you have your marathon fueling strategy locked in. Here’s what I did!

Lunch the day before the race:

pre-race meal gluten free

Dinner the night before the race:

I had both of those meals the day before multiple training runs and had great runs without any GI issues. So I knew weeks before the race what I’d be eating for lunch and dinner. I also knew it was going to be pretty crazy the night before the race getting into town, going to packet pick-up, going to the grocery store, and checking into our VRBO, so I actually baked sweet potatoes at home and packed them with me in a cooler to Wilmington. 🙂

Breakfast on the morning of the race:

  • Two pieces of Trader Joe’s gluten-free toast + peanut butter + banana
  • 1 glass water + 2 cups of black coffee
  • I drank 8 oz of Tailwind while driving to the race (about 30 minutes before the race start). My plan was to drink all 16 oz but I was too nervous. I should have started drinking this at home.

Tailwind review for running

Again, this pre-race meal was WELL tested in training runs. Do NOT try anything new on race day! (Or in the couple days before the race!)

Mid-race fuel, electrolytes & fluids:

Fuel: 30 minutes into the race, I had 1 GU. After that, I had one every 45 minutes or a little before 45 minutes. I NEVER went beyond 45 minutes!

  • I ended up taking 4 GUs – I took them at 30 minutes, 1:15, 2:00, 2:45, and 3:15. The last one was really more mental than anything since I didn’t have enough time for it to get into my system before I finished.
  • While I tried to take GU with water, if I wasn’t at a water station, I took it anyway at the 45 minute mark and then just got water at the next station.
  • My favorite GU flavor is Vanilla. I had 2 Vanilla, 1 salted caramel and 1 espresso flavor on race day.

Electrolytes: I took 2 Hammer Endurolytes tablets at every hour mark. This was a lot more than I’d trained with, but it was much warmer on race day than the 25* temps that I did the bulk of my training in.

Marathon Fueling Strategy

Fluids: I don’t tolerate Gatorade, which is what they had on the course, so I never touched that. (It seriously upsets my stomach.) So, I took water at every single aid station, never skipping, since it was warm and I struggled with dehydration in my training runs, even when it was cooler.

  • It was hard to tell who was holding water vs. gatorade since all the cups were the same and volunteers were mixed together (not the best method), so when I approached, I called out “water?”, made eye contact with a person who confirmed and then grabbed it from them.
  • I slowed a little bit but mostly ran through the aid stations, slowly sipping water as I jogged. Sometimes I slowed to a walk to swallow the electrolytes but only for about 5 steps since I didn’t want to walk too long. It’s too hard to get going again!


Similar to how I felt after all my long runs, I had no appetite after I finished the race. But, I knew my body needed fuel so I drank two bottles of water (one with Nuun in it) + a Larabar I had packed in my finish line bag (that Tommy had) within 30 minutes of finishing. Then, while I called my mom, I ate an RX Bar and a banana. We hung around until the awards ceremony (where I was shocked to learn I got 2nd in my age group!) and then drove back to our VRBO. I knew I needed more fuel, and randomly was craving sushi so we stopped at Harris Teeter, a grocery store whose sushi I knew I liked. Sushi + kombucha was a perfect post-run lunch!

what to eat after a marathon

I still didn’t have much of an appetite in the afternoon, but we went out for dinner that night and I had a big meal of fish (a huge portion, thankfully!), rice and salad. And a glass of wine to celebrate! (Side: I didn’t really get sore after the race and I think walking around was KEY. I blogged about that in my race recap.)

The bottom line: the best way to figure out what works well for you on race day is to practice during training.

If you are struggling in your training runs, ask for help. I doubled the amount of GU I was taking and added in the electrolyte tabs after I told some folks at my local running store that I felt terrible on my long runs. After we chatted a little bit more, they helped me realize that I was dramatically under-fueled.

If you’re interested in hearing more about how I fuel for workouts and races, sign up here to receive emails on that topic!


Shop the Post


terilyn signatureterilyn signature

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

    10 responses to “How I fueled for my marathon without any GI issues and ran a PR (3:28!)”

    1. This is so timely for me. I got injured last fall just over halfway through training for my first full, NYC. I drank – and loved – tailwind on long runs, but didn’t fuel. I got up, laced up and ran an 18 miler with just 3 dates in my pocket. So stupid. Since Jan, I still run a long run on Sundays, 10-12mi, just for fun with a friend. I know toast/PB/banana works. So that’s good. Training starts July 3, and I need to start figuring out fuel during. Also, I was going to fill an old water bottle with tailwind and start the race with it and just pitch it when it emptied, because like you, I can’t do gatorade. I never considered electrolyte tabs. Maybe that’ll be easier? To add to the stress, this race starts late morning and I have to travel for it…..

    2. Hi Teri – is your Running Gear page down, or is it just my computer? I’ve tried Firefox and Safari on a Mac, and my iPhone 6, but the main content part of the page is blank each time. The heading and sidebar work, though. I’m a brand new runner (literally only 2 runs under my belt so far!), so I’m going back and reading through most of your old posts for advice.

    3. ?Hello,

      My name is Tim Spears, I’m the business reporter for Spectrum News Charlotte.

      I’m looking for people with large social media followings for a story I’m working on about brand ambassadors.

      Any chance you’ve been contacted for paid ads on your IG or other social media? Would you be willing to talk about it for a story?

      Feel free to email back, or call/text 704.577.5443


    4. Huge congrats on your PR! PR’s always feel amazing, but not having any stomach issues during race day is also a huge win! I have yet to find anything that works well for me, so these tips are greatly appreciated!

    5. It’s crazy what a difference electrolytes made in how I felt after long runs. Typically if I ran more than 6 miles I would feel sick to my stomach all day. Then I started drinking coconut water after every long run (now I drink Nuun more often) and I always feel great!

      Thanks for sharing! I haven’t heard of a few of those products (Tailwind) and I’m excited to try them!

    6. Running and diet make a great duo. I’m not an athlete, but an enthusiast runner, i use SportMe marathon training which calculates distance, time, pace and calories.

    7. This is great timing! I just completed Ironman 70.3 in Wisconsin and learned some valuable lessons about fueling! The temps were humid and 93 degrees….I would have given anything to have some electrolyte tablets. GU started coming back up on the run, so I switched to Clif bloks (salted watermelon…new fave!) and was able to finish. I believe I was grossly under fueled. Thanks for the info on your fueling! I’m going to give some of this a try as I train for Ironman Wisconsin in September 🙂

    Leave a Reply

    Your email address will not be published. Required fields are marked *

    This site uses Akismet to reduce spam. Learn how your comment data is processed.