What to Eat on Long Runs: Nutrition Guide for Runners

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Nutrition for long runs is simple in principle: your body burns through its glycogen (stored carbohydrate) reserves at a rate that depletes them in approximately 90 minutes of moderate-intensity running. Once depleted, performance drops sharply and staying at pace becomes very difficult — this is “hitting the wall.” Fuelling during the run replaces glycogen and keeps you going.

In practice, runners get confused by the range of products available (gels, chews, bars, drinks) and by conflicting advice about how much to eat and when. This guide cuts through the noise.

When Fuelling Starts to Matter

Under 60 minutes: Water is sufficient for most runners. Your glycogen stores are more than adequate for a 60-minute run at moderate intensity, and eating during a short run provides no benefit and can cause GI discomfort.

60–90 minutes: A single small carbohydrate intake (one gel or 200ml of sports drink at the 45–50 minute mark) helps maintain energy and aids recovery. Not strictly necessary, but beneficial.

Over 90 minutes: Active fuelling is important. Without carbohydrate intake during a run of this length, most runners experience a significant drop in energy in the final third. For any long run over 90 minutes, plan your fuelling strategy in advance.

How Much Carbohydrate Per Hour

Sports science recommends 30–60g of carbohydrate per hour of running for most recreational runners. Highly trained endurance athletes can absorb up to 90g/hour, but the average runner benefits most from staying in the 30–60g range.

Common fuelling product carbohydrate content:

For a 2-hour long run, targeting 30–50g/hour means taking one gel every 30–35 minutes, or one every 45 minutes plus a sports drink, or real food equivalents.

Types of Fuel: What to Choose

Energy gels

The most portable, calorie-dense option. Most major gel brands are formulated with a combination of glucose and fructose, which are absorbed via different intestinal pathways — allowing higher total carbohydrate absorption without GI distress. Key brands:

• SiS Go Isotonic — the most commonly used gel in UK mass participation events; “isotonic” means it’s formulated to be taken without water. Widely available.
• Maurten Gel 100 — uses a hydrogel technology designed to reduce gut irritation; one of the most stomach-friendly options for runners who suffer GI issues with standard gels. Higher price point.
• GU Energy — strong flavour range, well-established, available at most running shops.

Always take gels with water (unless using SiS isotonic) — dry gels can cause GI distress.

Energy chews

Same carbohydrate profile as gels in a chewable format. Some runners prefer them because they feel less like “medical” nutrition. Slightly harder to eat at faster paces. Clif Bloks and Skratch Labs chews are popular options.

Sports drinks

Isotonic drinks (Lucozade Sport, High 5 Electrolyte, Maurten Drink Mix) provide both carbohydrate and electrolytes, replacing some of what’s lost through sweat. Good option if you prefer drinking to eating during runs. The carbohydrate density is lower than gels, so you need to drink more — factor this in when calculating whether you’re hitting your target.

Real food

A viable and often gentler option for slower, longer runs where you’re not racing:
– Banana (half every 45 minutes)
– Medjool dates (2–3 per hour)
– Rice balls (common in ultramarathon racing — white rice, salt, and a filling wrapped in cling film)
– Small pieces of flapjack or energy bar

Real food is less convenient and harder to eat while running at pace, but many runners find it much gentler on the stomach than gels.

Electrolytes: Don’t Forget Salt

Carbohydrate gets most of the attention, but electrolyte replacement matters for runs over 90 minutes, particularly in warm or humid conditions. The main electrolyte lost through sweat is sodium. Insufficient sodium can cause cramping, excessive thirst, and — in extreme cases — hyponatremia (dangerously low blood sodium, usually from over-drinking plain water).

Options:
– Isotonic sports drink (contains electrolytes; convenient)
– Salt tablets (e.g., Precision Hydration, High 5 Zero) — dissolve in water; high sodium content
– Electrolyte gels or chews that contain sodium

If your runs are under 90 minutes, or in cool conditions, plain water is fine. In hot weather or on runs over 2 hours, electrolyte replacement becomes progressively more important.

What to Eat Before a Long Run

Fuelling on the run starts before you run. A good pre-run meal 2–3 hours before:

• Bowl of porridge/oats — slow-release carbohydrate; doesn’t cause GI distress; classic pre-run choice
• Toast with peanut butter or banana — quick to prepare, easily digested
• Rice and a small amount of protein — common choice for runners who train in the afternoon

Avoid high-fat or high-fibre meals in the 2 hours before a long run — they slow gastric emptying and can cause GI issues during the run.

If running early in the morning and eating beforehand isn’t practical, a banana or a small snack 30–45 minutes before starting is better than running completely fasted for anything over 60 minutes.

Practising Your Fuelling Strategy

Always test your nutrition in training, not on race day. The gut is a highly trainable organ — runners who practise taking gels during long training runs experience far fewer GI issues on race day than those who use gels for the first time in a race. Specifically:

• Introduce gels during training runs progressively from 60–70 minutes onward
• Test the specific brand and flavour you’ll use on race day
• Establish the timing and quantity that works for you

Common causes of GI distress with gels: taking them without water, taking too many too quickly, using high-fructose gels without training the gut. All of these can be mitigated through practice.

Summary

Fuelling on long runs is simple once you have a system:

1. Start fuelling at 45–50 minutes on any run over 60–75 minutes — don’t wait until you feel depleted
2. Target 30–60g of carbohydrate per hour — roughly one standard gel every 30–40 minutes
3. Always take gels with water unless using an isotonic gel specifically designed to be taken without
4. Add electrolytes for runs over 90 minutes or in hot conditions — sports drink or salt tablets
5. Test everything in training before race day — your race-day nutrition should be a repeat of what you’ve already practiced

Next read: What to eat after a marathon: best recovery foods