There are mornings for soldiering through a few hours of intermittent fasting, but unless that's a tried and true method for your body, race-day morning shouldn't be one of those times.

For immediate and long-lasting energy to start strong and power you through, you need a good mix of nutrients like carbs, protein, and fat — in the right ratio — to boost satiety and endurance. To help you decipher what to eat on race day, here are five breakfast mistakes to avoid so you can cross the finish line strong. 

What to Eat on Race Day and Breakfast Mistakes to Avoid 

1. Don't Eat Something Brand New.

The most important sports nutrition rule is that you don't try anything new on race day.

Related: This Is How Leaky Gut Syndrome Directly Affects Your Workouts

“Even if it's a meal your friend eats or you read online that an elite athlete eats, that doesn't mean it will sit well with your body and help you perform your best,” Kelly Jones MS, RD, CSSD, LDN, says.

Everyone is different, so test drive the meal before one of your harder training workouts to see how your body responds. Then, you can either enjoy it or pass on it on those mornings that matter most.

2. Don't Go Low-Carb and too High in Protein.

Protein is important for recovery, but eating too much of it for breakfast on race day won't help you much.

"In fact, it may sit in your stomach and convert to usable energy very slowly during the race,” Jones says. 

Related: These Are the Best and Worst Carbs to Eat on Race Day

Carbohydrates are the quickest and most efficient source of fuel for the muscles — especially at high intensities — and they will support your central nervous system while racing. So when you're thinking of what to eat on race day, add protein if you want (yogurt or something small) but definitely don’t feast on steak and eggs.

3. Don't Eat Lots of Fat.

Like protein, fat shouldn’t be your go-to fuel on race day morning.

“Fat digests slowly and may linger in the stomach, increasing chances of gastrointestinal upset,” Jones says. “While some fat from nut butter or avocado with oatmeal or toast is okay, high amounts of saturated fats in bacon and cheese are less likely to sit well."

Save the sausage and cheese omelet for post-finish. (It'll be more satisfying then anyway.)

4. Don't Opt for High-Fiber Foods.

“Fiber is something I encourage any time of day except immediately before or during exercise," she advises. 'It's essential for gut health and all of its associated functions, but will sit in the stomach and other areas of the digestive tract, which can make you feel full and even lethargic."

Stick to just a smidge, such as the fiber in oats, toast, and nut butter, but skip anything bean or lentil-based, or any foods made of seeds such as chia, hemp, or flax.

5. Don't Skip It All Together.

We get it. You’re not a breakfast eater. But on race day, that hardly matters. You’re going to need the fuel.

“When you wake up, your muscle energy stores are depleted, which means you'll start feeding off of blood glucose sooner while competing,” Jones says.

Related: This Is What Happens to Your Body If You Don't Eat After a Workout

And if you really aren't interested in breakfast, just have something small.

“You still want to top off your energy stores with some carbs, even if it's as small as a banana a half hour before, or a tablespoon of honey five minutes prior to the race start,” she says.

Again, just be sure to test drive anything you eat days and even weeks before the race to avoid a digestive disaster.