Preparing for a half marathon isn’t just about perfectly planning out your running and strength training schedule. It’s also about mastering your nutrition needs, figuring out what to eat before a half marathon and what to snack on during your 13.1 miles.
The best way to nail fueling for a half: Incorporate nutrition and hydration strategies during your training to solidify that you’ll be fully prepared come race day.
To help you plan, dietitians share a few nutrition tips, including exactly what to eat before a half marathon, and how you can implement these fueling strategies now.
More From Runner's World
What to Eat the Day Before a Half Marathon
You might be wondering if it’s as necessary to carb-load for 13.1 as it is for 26.2. The short answer: no, but you still want more carbs. “You don’t need to carb load like you would before a marathon, because you will most likely be running less than three hours,” Megan Robinson, C.S.S.D, registered sports dietitian, and certified level 1 RRCA run coach tells Runner’s World. You do still want to shift your calories, though, so you’re eating more carbs, just like you would the day before a long run on your training plan, she says.
A mini carb-load prior to a half-marathon will still have a positive impact on your race performance. Technically speaking, carb-loading really comes into play any time you are out on the road for more than 90 minutes. But because it tends to lead to a bit of stiffness (because your muscles are fully stocked with glycogen) and water retention, it’s not recommended for events shorter than 90 minutes.
That means it can’t hurt to do a bit of carb-loading, especially since most of us take longer than 90 minutes to complete a half marathon. You can carb-load in as little as one day for a half marathon, but to prevent the worry of, “am I taking in enough?” aim to start two to three days before race day.
You don’t necessarily need to increase your calories—just make sure the majority of those calories come from carbs, especially at lunch and dinner the day before race day. If you normally fill half your plate with vegetables, Robinson suggests reducing that amount to about one-quarter to avoid any potential GI distress, and increasing your grain portion size to about half of your plate. Go for rice or pasta to fill that half of your plate. You can fill the remainder of your plate with lean protein like chicken, beef, or fish, she says.
Also the day before race day, have your main meal at midday and a smaller meal for dinner so you have plenty of time to digest. While you are at rest, your body will have adequate time and energy to absorb and store those nutrients you ate, and then you’ll be able to rely on this fuel for the following day. A great way to try this out while you’re training is to have this meal the day before your planned long runs.
What to Eat the Morning of a Half Marathon
The meal before the race is also very important, as you want to toe the starting line with a tank that’s primed, but neither empty nor overflowing. “Your prerace meal should be rich in carbohydrate to provide energy, with a little protein, fat, and fiber to stave off hunger during your race,” Kelly Jones, M.S., R.D., C.S.S.D., sports dietitian tells Runner’s World. Just like all your other meals, this should be something you’re familiar with and have trialed while training she says.
Not sure what to eat beforehand? Try a bowl of oatmeal topped with a sliced banana, nuts, and honey, or a bagel topped with nut butter and sliced banana, three hours before run time, Robinson suggests. With either of these options, “you’ll get quick and long-acting carbs as well as some protein, fat, and fiber to prevent a blood sugar spike and crash." Jones says.
What to Eat During a Half Marathon
Now that you know what to eat before a half marathon, it’s time to tackle the final question: “How do I avoid running on empty in those last few miles of the race?”
As you may have noticed during your training, when you’re on the road for fewer than 75 minutes, you can usually rely on water, sports drinks, and your body’s own glycogen stores to carry you along. Any longer, and you begin to deplete those stores. Your muscles run out of fuel, and your body—not to mention your attitude—starts to drag.
If you’ve ever had a long run that started strong and then got slower and slower, it may be time to consider what you did during the first few miles of the long runs that you didn’t do during the last few miles. Many runners head out the door with a full tank but, feeling great, they neglect to re-fuel over the next few miles.
If you don’t start fueling within that first hour, it’s likely that your empty tank will catch up with you, and you’ll bonk. Not only will you hit the wall, but once your muscle glycogen stores are depleted, it can also be very difficult to adequately recover during your run (and you may have to walk or crawl the last few miles).
To avoid this, you will need to replenish with carbohydrates, sodium, and fluids to maintain intensity and endurance, says Jones. Of course you don’t want to try anything new on race day. So aim to practice your race day nutrition on at least three of your long runs and during tempo runs, so you can monitor how your body responds to the type and amount of carbs you consume while running, says Robinson.
Robison suggests runners consume at least 30 grams of carbs every 30 to 40 minutes during the race. For those who predict they’ll finish in an 1.5 hours or less, fuel once mid-way through, she says.
Most importantly, don’t be afraid of fueling. If you’ve tried a product in the past and didn’t care for it or it didn’t sit well with you, then try something else.
Whatever concentrated form of fuel you are taking in, remember to dilute it with adequate water (or else it won’t be absorbed, and you will get nauseous).
Lastly, find out what gel or product your race will be handing out. If you can tolerate it or like the brand, you’ll know that you won’t need to pack your own on race day. You might also try to find out at what miles the race will be handing out product and mimic that in your training to practice for race day. But if the chosen brand doesn’t work for you, that’s when you want to plan ahead.
4 Great Energy Gels for Long Runs
CLIF SHOT Energy Gel
A quick hit of caffeine for when you need it most.
GU Energy Gel, 24 Count
A wide variety of flavors keeps your palette happy.
Honey Stinger Organic Fruit Smoothie Energy Gel
Organic, gluten- and caffeine-free ingredients you can actually pronounce.
UCAN Edge Energy Gel
This gel can be easier on the stomach.
The Bottom Line on How to Fuel a Half Marathon
Practice makes perfect. You can start mastering your nutrition needs as soon as you start training for your race. This doesn’t have be overly complicated process, you can start with the things you're already familiar with and like, then go from there.
Pamela Nisevich Bede, M.S., R.D., is the author of the newly released, Fuel the Fire, a nutrition and body confidence guidebook for the female athlete.
Monique LeBrun joined the editorial staff in October 2021 as the associate health and fitness editor. She has a master’s degree in journalism and has previously worked for ABC news and Scholastic. She is an avid runner who loves spending time outside.
