What to Eat Before an Ultramarathon¶
Eat what you already know works, two to three hours before the start, and keep race week boring. The bigger question is the hours after the start, because that is where most ultras are won or lost on food.
That holds for a first 50K and for a fifth hundred. The breakfast is the small part. It gets the attention because it is the part you can control from a kitchen.
What should I eat the night before an ultra?¶
Something you have eaten the night before long runs. Pasta, rice, potatoes, bread. Familiar, low in fiber, not spicy, not a restaurant you have never tried.
Race week is the wrong week to learn anything about your stomach. If a meal has ever sat badly during a long run, it is off the list, however good the advice that recommended it. If you travel to the race, pack the dinner or find out where you can get it. A town you do not know on Friday evening is a bad place to be improvising.
Eat until you are comfortable, not until you are full. A heavy meal at nine at night means a restless night and a stomach that is still working at the start line.
Sleep matters more than the meal. If nerves keep you from finishing dinner, eat what you can and move on. One light dinner does not decide a race.
What should I eat on race morning?¶
The same breakfast you have eaten before your long runs, two to three hours before the start. If the start is at 5 a.m., that means an alarm at 2 or 3. The point of the gap is to give your stomach time to empty before you ask it to work.
What tends to work: carbohydrate that is easy to digest, a little protein, very little fat and fiber. Toast with jam or peanut butter, oatmeal, a banana, a bagel, rice. Coffee if coffee is part of your normal morning. Nothing new.
If you cannot face food at that hour, a liquid breakfast or a few bites you can keep down is a fine answer. Then sip water or your drink mix until the start and take a gel or a few chews in the last 15 to 20 minutes if your stomach has handled that in training.
Two cautions:
- Do not skip breakfast to save your stomach. You are about to ask your body for many hours of work, and you do not start from empty.
- Do not eat a bigger breakfast than usual because the race is bigger. Your stomach does not know the race is a hundred. It knows the morning routine.
If you have a medical condition, take medication, or have a history of stomach trouble on long efforts, a sports dietitian or your doctor can set this up for you better than a blog post can.
Should I carb load for a 50K?¶
Carb loading means eating a very high-carbohydrate diet for a day or more before an event to fill muscle glycogen, the stored fuel in your legs. The International Society of Sports Nutrition's position stand on nutrient timing describes it as roughly 8 to 10 grams of carbohydrate per kilogram of body weight per day, for one to three days, along with a few days of reduced training.
That is a lot of food. For a 70 kg runner, 8 grams per kilogram is 560 grams of carbohydrate in a day. Eating that much on purpose takes planning, and it is not something to try for the first time in race week.
For a 50K, the practical version is smaller. Taper your running, which you are already doing. Eat a bit more carbohydrate than usual in the last day or two by making your normal meals more rice, potato, and bread, and fewer salads and beans. Do not turn it into a diet overhaul and do not eat until you hurt.
That is a judgment call, and a sports dietitian can give you a number built for your body. A longer race with a longer taper has more room for a proper load, and the same rules apply: practice it before a race that matters, because a high-carb day is a change your gut notices.
How much should I eat during an ultra?¶
The same ISSN position stand puts carbohydrate during long exercise at about 30 to 60 grams per hour. Ultra runners commonly aim higher than that, and the free ultra fueling calculator starts everyone at 60 grams per hour and moves up with time on feet and body weight, never above 120. Mixed glucose and fructose products let the gut absorb more, and a trained gut can take more again.
Here is what that looks like for a 160 lb runner expecting to be out for 10 hours in moderate conditions: 78 grams of carbohydrate per hour, 780 grams across the day. That is a lot of chewing, which is the honest reaction, and the reason real food and drink mix carry so much of a long day.
Three things hold for any distance:
- Start eating in the first 30 minutes. Hunger arrives late. By the time you feel it, you are already behind your plan.
- Eat on a clock. A watch that beeps every 20 to 30 minutes works better than memory at hour twelve.
- Expect the plan to bend. Heat, climbing, and bad patches change what goes down. Have a second option for when sweet stops working: broth, potatoes with salt, pretzels, a quesadilla.
A calories-per-hour number is only a starting point. Ultra fueling 101 walks the same math on paper, and real food fueling covers what to carry when gels stop appealing.
The practice that makes any of this work¶
Everything above, the dinner, the breakfast, the hourly numbers, is a guess until your stomach has tried it at effort and at hour four of a long run. That is the whole point of gut training for ultras: eat on your long runs, in the conditions you expect, with the exact products you plan to use. Then keep the ones that stayed down.
If something went wrong on a training run, you found out where it is cheap. Take that food off the list.
What the calculator is, and is not¶
The free ultra fueling calculator takes three things: your weight in pounds, your expected time on feet in hours, and conditions (cool, moderate, or hot). It returns carbohydrate, fluid, and sodium per hour, plus an hour-by-hour table with running totals you can check against at each aid station. No login.
It works from hours, not miles, because your stomach keeps time. It does not know your sweat rate, your history, or what your last long run did to you. Treat the numbers as a baseline and let your training correct them. It is not medical advice.
Questions¶
What should I not eat before an ultra?¶
Anything you have not eaten before a long run. High-fiber meals, very spicy food, and a large amount of fat close to the start are the usual causes of trouble. The rule is less about the food than about whether your stomach has met it before.
How long before an ultra should I eat?¶
Two to three hours before the start for a full breakfast. Closer to the start, keep it small and sugary: a gel, chews, or a few sips of drink mix, if you have trained with them.
Can I eat the same thing before a 50K and a 100 miler?¶
Yes. The morning meal does not change much with distance. What changes is the plan for the hours after the start, which grows with how long you will be out.
What if my stomach goes bad mid-race?¶
Slow down or walk, switch to small sips of liquid, and give it time before trying solid food again. If it keeps happening or you feel confused or unwell, tell aid station staff and get medical help.
Take it to the long run¶
Pick your breakfast. Eat it before your next long run. Write down what happened.