Ultra Fueling: Why Gels Alone Won't Get You to the Finish

Here’s a truth about ultramarathons that takes most people a race or two to learn: go far enough, and the best eater becomes the best runner.

Fueling matters in a half marathon and a marathon too. But over two, three, or four hours, you can train your gut to take in a steady stream of carbs from gels and chews and get to the finish on engineered products alone. Stretch the day to 8, 12, or 24 hours, in a long trail ultra or a backyard, and that plan starts to fall apart. Gels and chews are still part of the solution. They just can’t be the whole solution.

The day I threw up on the course

I learned this the hard way. My first ultramarathon was a 50K trail race. The year before, I’d run my first marathon on something like five gels. I knew the 50K was going to be significantly harder and that I’d need more calories, so I went nuts. Gel after gel after gel.

For the first 10 miles I actually felt pretty good. Somewhere around the midpoint it started to backfire. I got nauseous, and it kept building, and around mile 20 I threw up on the race course.

I felt better after that, but I was running on empty, low energy for the rest of the day. I got myself across the finish line. I’m proud I stayed in that race when I wanted it to be over. But I also didn’t touch another gel for a couple of years.

It wasn’t until I started reintroducing them slowly, and found some better ones, that I rebuilt my ability to take that kind of fuel in again. That slow rebuild is the whole lesson, and it’s the part most runners skip.

Engineered fuel plus real food

For most people running long ultras, the answer is a mix: gels, chews, and drink mixes combined with real food you actually enjoy. Lean carb-heavy, but it doesn’t have to be 100% carbs. If a little protein and fat helps your stomach settle and keeps things working, that’s okay. Everybody’s a little different here.

For me, it’s a trip back to childhood: peanut butter and jelly, and a little chocolate milk. I’ll be honest, I can overdo the chocolate milk. I don’t drink it day to day, but in an ultra I will, and I know that if I go overboard, my stomach will let me know.

I’ve seen people eat steak, burgers, chicken, all sorts of things out there. Everything is fair game, because the question isn’t what looks good on a nutrition label. The question is:

• What can you get down?
• What can you keep down?
• Does it make you feel good enough to keep going?

If the answer is yes to all three, it’s fuel.

Conditions matter too. If it’s hot out, you’ll want cold stuff. If it’s cold, you’ll want something hot. Liquid calories count as well, whether that’s a Tailwind-type drink mix or a Coca-Cola.

Train your gut like you train your legs

Most ultrarunners drift toward one of two approaches in training. A lot of people like to train fasted, carrying nothing and eating nothing. I think that’s a missed opportunity.

For a short, quick run, say 30 minutes, you don’t need anything. But once a run goes past an hour, even if you don’t feel like you need fuel, taking some in gives you two things:

1. Gut training. Your stomach adapts to taking in food while you run, the same way your legs adapt to mileage. Race day is the wrong day to find out it can’t.
2. Better recovery. Fueling during the run, and getting carbs in before and right after, helps you bounce back for the next session. Protein matters too, but I think it gets overemphasized at the expense of carbs.

My own habits have changed here. I used to take in basically nothing unless a run went over two hours. Now my line is about an hour, and sometimes I’ll take a little on shorter runs too, just for the practice and the recovery.

Use your long runs as the lab. Try different gels, different real foods, different drinks, in different combinations. Try them in the heat and in the cold. Heat and altitude can change how your stomach reacts to things you’ve eaten a hundred times, so test in the conditions you’ll race in when you can.

Why I love fueling in a backyard

One reason I love the backyard format is how much easier it makes eating. You come back to the same home base every single lap, so you can have every food you enjoy sitting right there. Depending on the race, and if you have a crew, someone might even be able to cook for you.

A point-to-point ultra is harder. You’re relying on aid stations and a crew leapfrogging ahead of you on the course, so everything takes more planning. In a backyard, the logistics are simple. That doesn’t make eating easy at hour 15, but it removes a lot of excuses.

When your stomach turns every time

If you’re the runner whose stomach turns at the same point in every long run or race, here’s where I’d start:

• What are you eating? Write down everything you take in and when.
• Is it 100% gels? If so, mix in some real food and see what changes.
• Are you drinking your calories? Drink mixes and soda count, and some stomachs handle liquid better than solid.
• What were the conditions? Heat and altitude change everything. A plan that works on a cool morning might fail in the afternoon sun.

Then keep experimenting. This is a hard problem, but it’s a solvable one. The more you train your gut, the more it can handle, and the more energy you’ll have when the race gets long.

Put a plan on paper

Intentions like “I’ll eat at the aid stations” don’t survive hour ten. Numbers written down ahead of time do. The ultra fueling planner turns your hourly carb, fluid, and sodium targets into race totals and an hour-by-hour checklist you can hand to your crew. Build it, test it on your long runs, and adjust it until it’s yours.