Fuelling Long Runs by Pace: 60, 90, 120 and 180 Minute Plans

Most runners know they should fuel a marathon. Far fewer have a plan for the Sunday long run, which is where the marathon is actually won or lost. The gut adapts to carbohydrate in the same way your legs adapt to mileage, and the only place to train it is in the sessions that last long enough to need it. Turn up to a two-hour run with a water bottle and good intentions and you will usually pay for it somewhere around the 80-minute mark.

The trouble is that generic advice ("take a gel every 45 minutes") ignores how long you are out and how fast you are running. A 4:30 marathoner and a 3:00 marathoner burn very different amounts of fuel per hour, and a 60-minute easy jog needs a completely different approach from a three-hour hilly effort. So here are four plans, built around duration, with real numbers you can adjust to your own pace.

Why Duration Matters More Than Distance

Your body stores roughly 400-500g of carbohydrate as muscle and liver glycogen, which is around 1,600-2,000 kcal. At moderate running intensity you burn through carbohydrate at something like 60-90g an hour, with the rest of the energy coming from fat. That means the tank is comfortably full for the first hour, starts to thin out from 90 minutes, and is properly depleted somewhere between two and three hours, depending on pace and how well you started.

This is why time on feet is a better guide than miles. Two runners covering 20 miles will have very different needs if one takes 2 hours 30 and the other takes 3 hours 30. It also explains why the fade tends to arrive suddenly: glycogen does not decline gently, it drops off a cliff when the liver can no longer keep blood glucose topped up. Fuel before that point, not after it.

The 60 and 90 Minute Plans

Up to 60 minutes: for an easy run you do not need to eat anything during the session. A normal meal two to three hours beforehand is enough. If it is a hard session (intervals or tempo), a few mouthfuls of carbohydrate or even a carbohydrate mouth rinse can help, but it is optional.

60 to 90 minutes: this is the grey area. Aim for 30g of carbohydrate per hour, starting at around the 30 to 40 minute mark. In practice that is a small handful of chews or a single gel taken in two halves. You are not trying to replace what you burn, only to keep blood glucose steady and teach the gut to cope with a little fuel while moving.

• Start at 30-40 minutes, then repeat every 20-25 minutes
• Take it with water, not with a sports drink, if you are using chews or gels
• Keep the first few weeks easy so your stomach has time to adapt

How to Fuel a 2 Hour Run

If you are wondering how to fuel a 2 hour run, the answer is 45 to 60g of carbohydrate per hour, starting early. Waiting until you feel hungry or flat is too late, because the signal arrives after glycogen has already dropped. A simple template looks like this:

• Before: 1 to 2g of carbohydrate per kg of body weight, two to three hours ahead (porridge, toast and honey, or rice are all fine)
• 0:30: first 15-20g of carbohydrate
• Every 20 minutes after: another 15-20g, which lands you at 45-60g an hour
• Fluids: 400-600ml per hour, more in warm weather, with sodium if you sweat heavily

Over the two hours that is roughly 90-120g of carbohydrate in total. Using a source that mixes glucose and fructose helps once you go above about 60g an hour, because the two sugars use separate transporters in the gut and you absorb more with less stomach trouble. Below 60g an hour, almost any carbohydrate source works.

A common mistake on this plan is treating the first half of the run as "free" and only starting to eat when things get hard. Knowing how to fuel a 2 hour run properly means the first gel or handful of chews goes in while you still feel fresh. Many runners also underestimate how much slower they run in the final 20 minutes when they skip fuel: a drop of 10 to 20 seconds per mile is typical, and it feels much harder than it should. Keep a note of what you took and how the last half hour felt, and adjust by 10g an hour next time.

The 180 Minute Plan and Beyond

At three hours you are in marathon territory and the target rises to 60-90g of carbohydrate per hour, depending on how well trained your gut is. If you have never taken more than 40g an hour, do not jump straight to 90g on race day. Build up by 10g an hour every week or two and treat it as a training adaptation, because it is one. Studies on gut training show measurable improvements in carbohydrate absorption and fewer symptoms after a few weeks of consistent practice.

For a 180-minute run, take fuel every 15 to 20 minutes rather than in big chunks. Small, regular amounts are easier on the stomach and keep blood glucose flat. Pace matters here too: if you slow to a walk on hills, that is a good moment to take on fuel and fluid. Finally, pay attention to hydration. Carbohydrate absorption is better when you are not badly dehydrated, and sodium losses of 500-1,000mg per hour are common in hot conditions.

Whichever plan you use, practise it in training with exactly the products you intend to use on the day. Nothing new on race day is old advice because it works.

What We Use at FTP Endurance Fuel

We built FTP around the problem of fuelling these longer sessions without paying gel prices or carrying a pocketful of sticky sachets. Our energy pastilles are easy to portion, which suits the little-and-often approach above: one or two every 15 to 20 minutes and you are on target without thinking about it. The Mixed Fruit Pastilles 1kg are a good all-rounder for running because the flavours keep things interesting over two or three hours, and the Tart Cherry Pastilles 1kg bring a sharper, less sweet flavour for the later miles. They are tart cherry flavoured; if you want real Montmorency tart cherry, it is in Power Fluids.

If you have not tried them before, the Taster Pack lets you test them on a long run before committing. Check the label for carbohydrate per serving so you can work out exactly how many to take per hour.

Putting It Into Practice

Pick the plan that matches your next long run, write the timings on your hand or set a watch alert every 20 minutes, and stick to it for four weeks. Most runners are surprised by how much easier the final 30 minutes feel once the fuelling is sorted. Ready to try it? Grab the bundles and put the plan above to the test on your next long run.