What to eat before a run: a plain-English guide

Start with the run, not the food

Two things decide whether you need to eat before a run: how long you'll be out, and how hard you're going. An easy 30-minute jog and a 90-minute long run ask very different things of your body, so there's no single answer to what to eat before a run.

The reassuring part is that most runs need very little planning. Your body stores carbohydrate as glycogen in your muscles and liver, and for short, easy running that's plenty to draw on. If you're new to all this, how to start running for beginners covers the first month in plain words.

Before an easy run of under an hour

You don't need anything special. If you've eaten a normal meal in the last few hours, you're set — an easy run at a conversational pace can run on what's already there.

First thing in the morning is the common worry. Half a banana or a few sips of juice is plenty, and if you'd rather head out on an empty stomach and feel fine, that's okay too. Take some water if it's warm.

Before a short or hard session

Hard sessions ask more. Intervals — repeated fast efforts with easy recovery jogs in between, such as 6 × 2 minutes quick with 2 minutes easy — and tempo runs (a sustained, comfortably hard effort you could just about hold for an hour) both want a little fuel on board. What are intervals? explains the format properly.

For most people, something light and carby 30–60 minutes before works well: a banana, or toast with honey. If you ate a meal in the last 3 hours, that already covers it, so don't double up.

Keep it small. A heavy breakfast still sitting in your stomach is the usual reason a session feels grim.

Before a long run or a race

For a run of 60–90 minutes, a light carb snack 30–60 minutes out is enough: a banana, a slice of toast, a small bowl of cereal.

Beyond that, aim for a proper carb meal 2–3 hours before you start: porridge, a bagel, rice or pasta. Keep fat and fibre modest if your stomach is sensitive — a big greasy or very fibrous meal is more likely to revisit you mid-run.

During the run itself, long runs are where you practise taking on carbohydrate. Start early, before you feel empty, rather than waiting for the slump at 25 km (15.5 miles) and trying to catch up.

What to drink

For most runs under an hour, a glass of water before you head out is enough. You don't need to carry anything.

On longer or hotter runs, sip 150–250 ml every 15–20 minutes, more in heat. Treat that as a pattern to practise rather than a target to force — drinking far more than you need leaves you sloshy and uncomfortable.

If you're out for a long time or sweating heavily, an electrolyte drink can replace some of the salt you lose. On shorter runs, water is fine.

Nothing new on the day

The most useful thing you can do with food is rehearse it. Use your long runs to test the breakfast, the timing and the snacks you plan to use in a race, so race morning holds no surprises.

If something doesn't sit well, that's useful information too. Better to find out on a quiet Sunday training run than halfway through a half marathon.