What to eat before a half marathon: day before, night before, morning

What you eat before a half marathon matters less than what you've done in training, but it can still make or break the morning. The goal is simple: start with your carbohydrate stores topped up and your stomach calm. That means carb-forward, familiar food the day before, a plain dinner the night before, and a breakfast you've already tested.

This is general information for healthy adult runners, not individual advice. If you have diabetes or prediabetes, a GI condition such as IBS or celiac disease, kidney disease, a history of disordered eating, are pregnant, or have any other medical reason to watch what you eat, plan your race fueling with your doctor or a registered dietitian.

How much the half marathon depends on food

A half marathon sits on the border where pre-race eating starts to matter a lot. Carbohydrate stored in your muscles and liver (glycogen) is the main fuel at race effort, and the longer you run, the more likely you are to run low.

A review table by sports nutrition researcher Louise Burke puts the full carbohydrate load (36 to 48 hours of very high carb intake plus a taper) in the category of events that usually last more than 90 minutes. A Gatorade Sports Science Institute review adds that for events under 90 minutes, such aggressive intakes may not be necessary, and cites a 1981 study in which more dietary carbohydrate raised muscle glycogen but didn't improve treadmill half marathon performance.

Our reading of that for the half marathon:

• If you'll finish in under about 90 minutes, eat normally with a carbohydrate tilt the day before. A formal carb load isn't needed.
• If you'll be out there longer than 90 minutes, as many recreational runners are (see the half marathon pace chart), a bigger carbohydrate emphasis the day before and some fuel during the race make more sense. Our carb loading guide explains the full method if you want to go further.

Either way, the race-week rule is the same: nothing new.

The timeline at a glance

The targets come from the research reviews cited below; the example foods are our suggestions. The sections below go through each step.

The day before a half marathon

The day before is about steady, carb-forward eating, not one giant meal. Build each meal around a starch and keep the portions of fat, fiber and protein moderate.

Cleveland Clinic's race-week advice, from sports dietitian Carly Sedlacek, is written for the marathon, but its food choices suit a half just as well. It favors simple, lower-fiber carbohydrates like white pasta, rice, bread and low-fiber fruit, and lists easy options such as white toast with jam, a bagel with peanut butter, a turkey sandwich on white bread with pretzels, applesauce, rice cakes with honey and cereal with milk. It also points out that carbs are stored with water, so drink well, and suggests cutting back on alcohol in the weeks before the race.

A sample day before:

• Breakfast: low-fiber cereal with milk and a banana, plus juice.
• Lunch: turkey sandwich on white bread, pretzels, applesauce.
• Snack: rice cakes with honey, or a bagel with a thin layer of peanut butter.
• Dinner: see the night before, below.

If whole grains, beans and big salads are your everyday staples, the day before is a sensible time to swap some of them for lower-fiber versions. You aren't changing your diet, just making it gentler on your gut for 24 hours.

What to eat the night before a half marathon

Dinner the night before should be boring in the best way. Cleveland Clinic suggests white pasta with marinara sauce, or rice with a small amount of lean protein, and lists four things to limit: high-fiber foods, high-fat foods, spicy foods and dairy. A position stand from the International Society of Sports Nutrition also warns against eating or drinking too much before competition.

Good night-before dinners:

• Spaghetti with marinara, a few pieces of grilled chicken, white bread.
• Rice with a little baked fish or tofu and well-cooked carrots.
• A baked potato (skin off if you're fiber-sensitive) with a small portion of lean meat.
• Plain pancakes or French toast with syrup, if that's what your stomach likes.

Eat at your normal dinner time and stop when you're comfortably full. An oversized dinner can leave you feeling heavy on race morning.

What to avoid the night before: creamy or fried dishes, chili and curries with heavy spice, bean-heavy meals, large salads, a first try of a new restaurant, and alcohol.

What to eat the morning of a half marathon

Breakfast tops up the liver glycogen used during the overnight fast. Burke's review table recommends 1 to 4 grams of carbohydrate per kilogram of body weight, 1 to 4 hours before the start. A sensible way to use that range: the more time before the gun, the more you can eat.

For a 150 lb (68 kg) runner, that range works out to:

To get your own number, divide your weight in pounds by 2.2046 to get kilograms, then multiply.

What 100 grams of carbohydrate looks like, using USDA FoodData Central values:

• A 100 g (3.5 oz) plain bagel: about 52 g of carbohydrate (USDA).
• A 120 g (4.2 oz) peeled banana: about 27 g (USDA).
• 25 g (0.9 oz) of honey: about 21 g (USDA).

Together that's about 100 g, roughly 1.5 g/kg for a 150 lb runner, which suits a breakfast 2 to 3 hours before the start. Bagel sizes vary a lot, so check the label on yours.

Other race-morning breakfasts that fit:

• White toast with a thin layer of peanut butter and banana slices (Cleveland Clinic suggests "a little" peanut butter, which keeps the fat modest).
• Oatmeal made with water or milk, topped with honey or maple syrup. Dry oats carry about 10 g of fiber per 100 g against under 3 g for white bread (USDA oats, USDA white bread), so test this in training.
• Plain waffles or pancakes with syrup.
• A rice bowl with a little egg, if a savory breakfast sits better.

Drink with breakfast, then sip water until you head to the start. If the race starts early, set an alarm to eat and go back to resting.

If you can't eat much on race morning

Nerves can blunt appetite. Liquid carbohydrate (juice, sports drink, a smoothie made with banana and milk) may be easier to get down. The ISSN position stand reviews studies of carbohydrate taken 30 to 60 minutes before exercise, with mixed results: one found a gain in exercise capacity, and a review it cites found no harm to performance. So a small, late snack you've tested is a reasonable fallback. If your stomach is very sensitive, eat earlier and lighter, and practice exactly that before a long run.

Eating during a half marathon

Burke's review recommends 30 to 60 grams of carbohydrate per hour for events of 1 to 2.5 hours. For hard efforts of about 45 to 75 minutes (it names the half marathon as an example), it notes that the benefit comes mainly from frequent contact of carbohydrate with the mouth, including a simple mouth rinse, rather than from the fuel itself.

What that means in practice:

• Under about 75 minutes: frequent sips of sports drink at aid stations cover it.
• About 75 minutes to 2 hours 30 minutes: aim for 30 to 60 g per hour. For a 2:15 finish, that's about 68 to 135 g across the race. Gels vary, so read the label: at 25 g per gel, that's roughly 3 to 5½ gels' worth, counting any sports drink you take.

Asker Jeukendrup's 2014 review is clear that you should practice your race fueling in training to reduce the chance of stomach problems. Use your long runs in a half marathon training plan to test the exact gel, chew or drink you'll race with, and find out what the race will hand out on the course.

Common mistakes

• Trying something new. A new gel from the expo, a new breakfast, or a big unfamiliar restaurant dinner is the classic way to ruin a well-trained race.
• One huge pasta dinner instead of steady carbs all day. Spread it out.
• Too much fiber or fat in the last 24 hours. Fine for everyday health, rough on race morning.
• Skipping breakfast for an early start. The low end of the research range, 1 g/kg, is a small meal: about 68 g of carbohydrate for a 150 lb runner.
• Under-fueling a 2-hour-plus race. If you're running toward a goal such as a sub-2-hour half marathon, practice taking carbs at race pace, not just at easy pace.

For a full marathon the stakes go up. Our guide to what to eat before a marathon covers the longer lead-in.