What Should You Eat and Drink During a Marathon?

Haggai Leffler — The Vegan Athlete. What to eat and drink during a marathon, with contributing running coach Yotam Kaplan (an Israeli marathoner).

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In the previous article, we covered what to eat before a marathon and why.

Today, let's talk about what to eat and drink during the race—and whether you need to.

During an intense run, your body relies heavily on glycogen, its readily available carbohydrate reserve.

Even if you've done your carb-loading properly, longer races—a half marathon or full marathon—can demand more carbohydrates than you have stored.

As those stores run low, your body has to rely more on other fuel sources, such as fat. Fat can't supply energy as quickly as carbohydrates, which can make it harder to maintain your pace.

That's why we want to keep fueling during the race, rather than waiting for the tank to run dry.

So how do you fuel?

First, let's break it down by race distance, just as we did in the previous article.

If you're running a 5K or 10K, you generally don't need to take in extra energy during the race because you're running for a relatively short time.

For half-marathon and marathon runners, on the other hand, fueling during the race deserves a place in the plan—not an afterthought.

What's the rule of thumb?

A starting point is about 100 calories every 40 minutes, with your plan adjusted to your needs and race duration. 

There are several ways to get that fuel: an energy gel (most are vegan, but check the label), 2 dates, 3–4 dried apricots, a can of cola, or other easy-to-digest options. These aren't exact calorie equivalents; portions and products vary.

Choose what agrees with your body and what you've already tested on training runs. Haven't tested your fuel yet? Training is the time to do it.

I'm not exactly a gel enthusiast. Honestly, I find the taste pretty gross. But convenience counts on race day, so I use them anyway.

The biggest rule bears repeating: nothing new on race day. Not even a new flavor or brand of gel. Show up with a plan you've practiced. You can't predict how your gut will react to something unfamiliar, and a race is a terrible place to find out.

Two other things to plan for: electrolytes and fluids.

Electrolytes

Salt tablets have gotten more attention among distance runners lately. Still, plenty of runners head into long races without thinking about how to replace the sodium they lose in sweat. The important thing is an appropriate hydration and electrolyte plan—not assuming everyone needs a pill.

Half-marathon runners generally don't need salt tablets automatically. If you'll be out there longer than 2½ hours, it's especially hot, or you know you sweat heavily, give your electrolyte needs extra attention.

For a full marathon, a schedule of one salt tablet every 45–60 minutes isn't a universal prescription: tablets contain different amounts of sodium, and your needs depend on the weather, your sweat losses, and what you're already getting from drinks and fuel. Work out an individualized plan rather than dosing by the clock alone.

Fluids

Hydration is every bit as important as food—and can be the bigger concern. Every year, runners become dehydrated during marathons after failing to keep up with their fluid needs.

For some, mild dehydration hurts their performance. For others, dehydration and heat illness can become serious enough to cause collapse.

Most races have plenty of water stations. Use them as regular opportunities to check in with your thirst and take a few sips when you need them, rather than feeling obligated to drink at every stop.

Sometimes drinking feels like one more chore while you're running. You're still losing fluid through sweat, so don't ignore hydration—but don't force water down just because it's available, either.

Thirst is a useful guide, not proof that you're already too late. Drinking too much can also be dangerous.

The takeaway:

Pay attention to hydration from the start. Have a plan you've practiced, use the water stations, and adjust your intake to your thirst and the conditions instead of waiting until you feel unwell.

Unfortunately, I learned the dehydration lesson the hard way during the full Tel Aviv Marathon (a road race in Israel) two years ago.

It derailed my target time and turned the final 10 kilometers (6.2 miles) into the longest stretch of running of my life.

Of course, hydration needs to be part of your training runs, too.

You can stash a bottle along your route, ask a friend or family member to meet you with water and a little encouragement, or stop briefly at a drinking fountain.

There's no single right answer to exactly how much you should drink. Your body weight, sweat rate, the weather, and other factors all play a role. Listen to your body and use your training runs to learn what works. Take a few sips when you need them, without forcing yourself to drink beyond thirst.

Bringing it all together: 

We've covered how to fuel your body during a marathon, and when midrace fueling is needed in the first place.

I hope that clears up some of the confusion. If you still have questions, send them my way.

In the next and final article, we'll get to the best part… you've crossed the finish line!

Now, what should you eat to help your body recover?

Spoiler: it's not the yogurt the Muller (a dairy brand) reps—or any other company's reps—are handing out at the finish.

Vegan coaches, nutrition professionals, and physical therapists interested in contributing to The Vegan Athlete: send your article pitches to lefflerpro@gmail.com.