I made a big fueling mistake before my first 10K race—here’s what a dietitian says to do instead

One of the biggest mistakes I made when running my first 10K race was assuming that nutrition wasn’t really important for such a distance.

I had my usual breakfast of Greek yoghurt, homemade granola packed with seeds and blueberries. a few hours before the race, skipped the pre-race snack and, aside from a few sips of water, didn’t eat anything until I got home a few hours later.

Cue post-run cramps and a massive energy dip.

I learned the hard way that fueling properly before and after a run matters. Whether you’re running 10K or a marathon, getting it right helps maintain energy levels and supports both performance and recovery.

To avoid repeating the same mistake as I prepare for my next run, I spoke to sports dietitian and runner Amy Goblirsch—known online as The Running Dietitian—to get her advice on how best to fuel and refuel for a 10km race.

Here’s what she recommends considering before the start line, and after the finish line.

Pre-race nutrition

While carb-loading isn’t necessary for a distance of 10K, Goblirsch does recommend slightly increasing your carbohydrate intake the night before.

“Increase the carbohydrate portion you’d normally have at dinner to build up your glycogen stores,” she suggests.

This could mean adding an extra portion of rice, potatoes, pasta, or bread to your dinner to top up energy levels.

On race day, Goblirsch suggests eating breakfast two to four hours before the start line. Focus on a meal that’s mostly carbohydrate-based and easy to digest.

“Good options include oatmeal with fruit, toast with peanut butter and a banana, or a bagel with nut butter and honey,” says Goblirsch.

I had my pre-race meal just under four hours before my run, and I was already hungry by the time I crossed the start line. If you’re anything like me, Goblirsch recommends a pre-race snack for an energy boost.

“About 15–30 minutes before the start, you could have a quick carbohydrate source. Something like sports chews or gels, stroopwafel, or a banana.”

Post-race nutrition

Now comes the refuel. Goblirsch recommends eating 30-45 minutes after running, having a snack that includes carbohydrates to replenish energy stores, protein to support muscle recovery, and fluids to help with rehydration.

“Something like chocolate milk is often handed out after races because it hits all these marks,” she says. Chocolate milk contains what Goblirsch calls the “ideal carb-to-protein ratio”, and is easy to grab on the go.

Granola bars or fruit also work well as an initial recovery snack, but you should think about when you’ll have your next proper meal too.

“Ideally, you will have a balanced meal with carbohydrates, protein and fats within 90 minutes of finishing the race,” says Goblirsch. If that’s likely to be delayed, she suggests having another small snack to help bridge the gap.

Ultimately, you’ll discover what’s right for you with trial and error, so it’s a good idea to experiment with fueling and refueling during training. It’s something I’ll be doing in future.

What works for one runner, might not work for another, so use your training as an opportunity to test out different foods and meal timings. Find what suits you, and avoid trying anything new on race day.