How to Fuel for Long Runs

Choose a familiar carbohydrate-rich meal about three to four hours before running, or a smaller snack one to two hours beforehand. Toast, cereal or fruit are options; timing and portions depend on what you tolerate. Large amounts of fat or fibre close to exercise can cause discomfort.

The Australian Institute of Sport gives a target of 30–60 grams of carbohydrate per hour for endurance exercise lasting one to two-and-a-half hours. For events longer than roughly two-and-a-half to three hours, up to 90 grams per hour may be appropriate, using mixed carbohydrate sources such as glucose and fructose.

The higher end is not a starting requirement for every runner. Practice a manageable amount in training, then adjust for duration, effort and gut comfort. Gels, chews, drinks and familiar foods can all contribute. Count carbohydrate from everything you consume.

If your practiced target is 40 grams per hour and your gel contains 20 grams, two gels per hour provide that amount. Over a four-hour event, that is eight gels if you get no carbohydrate from drinks or food. A 25-gram gel changes the calculation, so check your own product rather than following a universal gel count.

Write your plan in grams and hours first, then map it to what you can carry and the aid stations available. Start taking regular small amounts early rather than waiting until you feel depleted.

Fluid needs vary with the runner, conditions and effort. Thirst is a useful real-time guide; do not force a fixed volume simply because it is on a schedule.

Drinking more than your body can handle can cause dangerously low blood sodium (exercise-associated hyponatremia). Sports drinks and salt supplements do not prevent this if you overdrink. A personalised strategy is preferable to treating an electrolyte product as insurance.

Include carbohydrate to replenish fuel and protein to support repair in your next meal or snack. Yogurt with fruit, a sandwich or rice with eggs are straightforward options. Prompt refuelling matters especially when another session follows within eight hours; there is no universal 30-minute deadline that makes a later meal worthless.

Check what the organiser supplies, including serving sizes. Try your chosen products, carrying setup and timing on training runs before relying on them in a race. If you repeatedly struggle to eat or drink comfortably, seek individual advice rather than continually increasing your intake.