When to take a GU energy gel (before you're already crawling)

You've got your favourite selection of GU Energy gels. You know what they do. You know why they work. Now comes the part where most people still get it wrong.

They wait. And wait. And then, at kilometre 28, when their legs have already started sending resignation letters, they eat three gels in a row and wonder why they feel sick.

Don't be that person. Here's how to actually time it.

Start before you need it

This is the one rule that matters more than any other: fuel before you feel flat, not after.

By the time you notice your energy dropping, your glycogen stores are already critically low. The gel you take then needs 10 to 15 minutes to kick in, which means you're running on fumes for the best part of 20 minutes. In a race, that's an eternity.

Fuelling is not a rescue plan. It's a maintenance schedule.

First gel at 20 to 30 minutes

Take your first gel 20 to 30 minutes in, before you feel you need it. Then little and often: something every 20 to 40 minutes, with sips of water as you go.

For a 3-hour long run at about 60 g of carbs an hour, that's around eight standard gels, or fewer if a drink mix is doing some of the work. How many gels for a 3-hour race has the sum.

Adjust for how long you're out

• Under 60 min: no gel needed, water to thirst.
• 60 to 150 min: 30 to 60 g of carbs an hour, so one or two gels an hour.
• Over 150 min: around 60 g an hour. More than that only with a trained gut and mixed glucose and fructose products.

Caffeine energy gels: save them for when you need the edge

Caffeinated GU Energy flavours are most useful in the back half of a long effort, when your legs are tired and your brain is trying to negotiate an early finish. Using them too early wastes the effect. Save them for the final hour, or a section you know is going to be rough.

A note on gut issues

If energy gels have ever made you feel sick mid-run, the most likely culprit is one of three things: you took it without water, you took it too late (already dehydrated), or your gut just hasn't practised enough.

The cure is boring but true: use gels in training, regularly, at race effort. Your gut is trainable. Give it a chance to catch up.

The messiest runs teach you the most. Spill a gel, bonk once, forget to drink, then never do it again.

Build the habit in training. Trust it on race day. Fuel first, every time.

That's the GU Energy gel series done. Next, we go deeper: hydration, recovery, race-specific plans, and the art of eating real food while moving fast through the mountains.

Frequently asked questions

When should I take my first gel?

Around 20 to 30 minutes in, before you feel any energy drop. By the time you notice you're flagging, you're already behind, and a gel takes 10 to 15 minutes to kick in. Little and often from early on beats catching up later.

How many gels do I need for a long run?

For a 3-hour run at about 60 g of carbs an hour, roughly eight standard gels, fewer if you use a drink mix too. Going above 60 g an hour takes a trained gut, so build up to it in training.

When should I use a caffeinated GU gel?

Save caffeine gels for the back half of your run, the final hour, or any section you know is going to be rough. Using them too early burns through the effect when you don't need it most. Think of them as a tool for the hard part, not the warm-up.

Why do gels make me feel sick?

Usually one of three things: you took it without water, you took it too late when you were already dehydrated, or your gut hasn't had enough practice at race effort. The fix is boring but it works: use gels regularly in training at the same intensity you race. Your gut adapts, it just needs the reps.

Do I need a gel for a run under an hour?

Not usually. An easy run under 60 minutes at moderate effort is well within what your glycogen stores can handle without top-up. Save the gels for sessions over an hour, hard efforts, or back-to-back training days where your stores are already depleted going in.