OUTRN

What to Eat Before a Run: Timing, Foods and the Evidence

Training | Published 2026-10-03 | By OUTRN Team

The OUTRN team goes through when to eat, how much, which foods, fasted running and what to eat after a run, and where the research is thinner than the advice...

Everyone has a pre-run breakfast opinion, and most of them are stated with more confidence than the research allows. Here is the strongest finding, and it is oddly boring: for longer runs, eating something beats eating nothing, and the exact food, amount and timing matter less than people think...

The short answer: for a run longer than about an hour, eat a carbohydrate-based meal 3 to 4 hours before or a lighter snack 1 to 2 hours before, keep fat low and fibre moderate, and have fluid with it. For shorter runs, what you eat matters little. This guide is for someone who runs at least 10km comfortably and is training for a longer event.

A note on sources: the Australian Institute of Sport (AIS) fact sheets on eating before exercise, recovery and carbohydrate are from 2009 and 2014, are no longer live on the AIS site, and are cited through archived copies. Treat them as dated official guidance. The AIS pages on gels, drinks and caffeine are live.

When should you eat before a run?

The AIS gives a general guide: a meal about 3 to 4 hours before exercise, or a lighter snack about 1 to 2 hours before, and says you need to experiment to find the timing and amount that suits you. For events longer than 60 minutes, its 2014 carbohydrate table suggests 1 to 4g of carbohydrate per kilogram of body weight, eaten 1 to 4 hours before. For a 70kg runner, that is a wide 70 to 280g.

How much does the timing matter? A narrative review (Rothschild and colleagues, Nutrients, 2020; it pooled 125 studies for its fuel-use data) concluded the amount of carbohydrate eaten (25 to 312g across studies) did not have a meaningful influence on time trial performance, and timing had minimal effect at gaps of 15, 45 or 75 minutes. Its conclusion: eating versus not eating has a far larger effect than the amount or timing of the meal, unless the timing differs by at least 90 minutes. About 87 percent of the participants in its pooled data were men.

Does eating before a run improve performance?

For longer efforts, yes. A meta-analysis of 46 studies (Aird and colleagues, Scandinavian Journal of Medicine and Science in Sports, 2018) found eating before exercise improved prolonged aerobic performance (P = 0.012) but not shorter-duration aerobic performance (P = 0.687). The abstract does not give a threshold in minutes, though Rothschild's review puts it at over about 60 minutes.

What should you eat?

Carbohydrate that is low in fat and moderate in fibre, according to the AIS, because foods higher in fat, protein and fibre take longer to digest and may raise the risk of stomach discomfort. The AIS adds that running, where the gut is jostled about, is harder on the stomach than sports where the body is supported. Its examples:

The AIS 2014 "50g of carbohydrate" table helps with quantities: 60g of wheat biscuit cereal (5 biscuits), 100g of bread (4 slices white), 2 medium to large bananas, 180g of boiled rice, 200g of boiled pasta, or 350g of potato each supply about 50g. Check labels, as brands vary.

Here is the honest part. There is little running-specific trial evidence on fat, fibre and protein before a run. The advice is digestion logic plus official guidance. Rothschild's review lists gut comfort after different pre-run meals as a research gap, and a review of gut problems in athletes (de Oliveira and colleagues, Sports Medicine, 2014) found 30 to 50 percent report gut complaints, with no single food fix proven.

Does the glycaemic index matter?

Not clearly. The AIS says research has been unable to show universal benefits from low-glycaemic-index foods before exercise, and that many low-GI choices such as lentils, porridge and multigrain bread may upset the stomach. Rothschild found a small effect at most. The International Society of Sports Nutrition's ultramarathon position stand (Tiller and colleagues, 2019) prefers low-GI carbohydrate for the pre-race meal in ultras. So there is no clear winner: eat what you tolerate. Solid, liquid or gel pre-exercise carbohydrate showed no performance differences in the studies Rothschild reviewed.

Will eating before a run give you low blood sugar?

Rarely. The AIS says most athletes can eat carbohydrate in the hour before exercise without harm, but a small percentage experience a dip in blood glucose with fatigue, shakiness or dizziness. If you are sensitive, it suggests leaving longer between eating and running, having a larger snack (at least 70g of carbohydrate) if you eat close to the start, doing a higher-intensity warm-up and taking carbohydrate during the run. Rothschild agrees it occurs in a small number of cases, with no apparent detrimental effect on performance.

Should you run fasted?

If your goal is performance, eat first. The AIS puts it plainly: if your primary goal is to improve performance, have something to eat before exercise.

A meta-analysis of 27 studies and 273 participants (Vieira and colleagues, British Journal of Nutrition, 2016) found fasted aerobic exercise burned about 3g more fat during the session (95% confidence interval 0.8 to 5.4g). That is acute fat burning, not fat loss or a faster race. Training with low carbohydrate on selected sessions did not improve endurance performance on average in a meta-analysis of 9 studies in well-trained athletes (Gejl and Nybo, 2021; standardised mean difference 0.17, confidence interval -0.15 to 0.49).

For weight loss, the AIS says that if you will do the same amount of exercise whether you eat or not, you can save your meal until after the session. If weight loss is your goal, speak to a dietitian.

What should you eat before an early morning run?

If you cannot eat 3 to 4 hours before, the AIS suggests a light snack about an hour before, such as some fruit or a cereal bar with a glass of milk or juice, and making up for the smaller intake by taking carbohydrate during the run. For an easy run of under an hour, water alone may be enough. The AIS's distance running sheet (2009, written for its national-team runners) notes that if the aim is just to log distance, some water may suffice and may even enhance the session, but that idea rests on training with low carbohydrate, whose performance benefit has not been shown, so we would not push it on long-run days.

What should you eat on race morning?

The same AIS distance running sheet suggests a meal rich in carbohydrate and low in fat, fibre and protein, such as toast or plain muffins with jam or honey, or pancakes with maple syrup, and liquid meals when you are nervous or short of time. The International Society of Sports Nutrition's ultra position stand adds a familiar, easily digestible meal. In the 100km cycling trial used in carb loading research (Burke and colleagues, 2000), trained cyclists ate 2g of carbohydrate per kilogram two hours before and 1g per kilogram per hour during. That is a lab protocol, not a marathon recommendation. For what to take in the race itself, see our carb loading and fuelling guide.

What should you drink before a run?

Start hydrated, and do not overdo it. An American College of Sports Medicine position stand (Sawka and colleagues, 2007) says the goal is to start exercise euhydrated and with normal plasma electrolytes, and that extra drinks, when needed, should be started at least several hours beforehand. The AIS's 2009 fluid sheet says to drink regularly through the day and with meals, and to drink 200 to 600ml immediately before exercise. We could not verify the stand's exact volume.

The advice on thirst has moved. The AIS 2009 fluid sheet tells people drinking water during exercise not to rely on thirst, but the 2015 international consensus statement on hyponatraemia (dangerously low blood sodium), as summarised in a 2017 update co-written by its lead author (Hew-Butler and colleagues), says drinking to thirst prevents it in temperate conditions in events under about 17 hours. We cover that in our first ultra guide. To test your own sweat rate, the AIS method is to weigh yourself before and after a run, add the fluid you drank and subtract urine: each kilogram lost is about a litre.

What should you eat after a run?

The AIS's 2009 recovery sheet recommends a carbohydrate-rich snack or meal providing 1 to 1.2g of carbohydrate per kilogram of body weight in the first hour, because that is when glycogen is rebuilt fastest, and says it matters most if you will train again within 8 hours. For a 70kg runner, that is 70 to 84g, about 1.4 to 1.7 of the 50g portions above (our arithmetic). A review of the muscle glycogen literature (Burke and colleagues, Journal of Applied Physiology, 2017) found about 1g per kilogram optimises glycogen in the first four hours, and that over the following 4 to 24 hours total intake matters more than type or pattern. So if your next run is a day away, do not stress about the first hour.

Protein helps recovery, with less certainty. The AIS says to have 15 to 25g in the first hour, and the International Society of Sports Nutrition's protein position stand (Jäger and colleagues, 2017) suggests about 0.25g per kilogram or 20 to 40g per serving, with 1.4 to 2.0g per kilogram a day enough for most people who exercise. Most of the dose evidence comes from resistance training. The AIS says to drink 125 to 150 percent of your fluid loss over 4 to 6 hours.

Examples that provide about 50g of carbohydrate with useful protein, from the AIS: 600mL of low-fat flavoured milk, a large bowl of cereal with milk, 220g of baked beans on 2 slices of toast, or a bread roll with cheese or meat plus a large banana.

What should you eat every day?

The AIS 2014 table sets 5 to 7g of carbohydrate per kilogram for about an hour of training a day and 6 to 10g per kilogram for 1 to 3 hours a day, rising on hard days and falling on easy days. If you train about an hour a day, you sit in the first band.

Where does the evidence run out?

Inspired? Try your breakfast on a long day with a crew

Our Blue Mountains trip has a long day built in for testing your plan: the Sunday Six Foot Track run, about 28 to 30km with more than 1,000m of climbing on the return, or a shorter 15 to 16km turnaround. All meals are included. Dates are to be confirmed and the price is an estimate of about $1,650 per person. Booking is not open yet, so register your interest and we will contact you first.

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References

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Frequently asked questions

What is the best thing to eat before a run?

A carbohydrate-based meal or snack that is low in fat and moderate in fibre, according to the Australian Institute of Sport (AIS). Examples it lists include toast with jam or honey, cereal with milk, a banana, a baked potato, or pasta with a low-fat sauce. A 2020 review found that eating something before exercise matters more than how much you eat or exactly when.

How long before a run should you eat?

The AIS gives a general guide of a meal about 3 to 4 hours before exercise or a lighter snack about 1 to 2 hours before, and says to experiment to find what suits you. A 2020 review found timing within about 90 minutes made little difference to time trial performance.

Is it better to run fasted?

Not for performance. A meta-analysis of 46 studies found eating before exercise improved prolonged aerobic performance but not shorter efforts, and a meta-analysis of nine studies in well-trained athletes found training with low carbohydrate did not improve endurance performance on average. Fasted exercise burns more fat during the session, but we found no evidence that it improves performance, and we did not find fat-loss trials.

What should you eat before a long run or marathon?

The AIS suggests a carbohydrate-rich, low-fat, low-fibre, low-protein meal such as toast or plain muffins with jam or honey, or pancakes with maple syrup, and the International Society of Sports Nutrition adds that it should be familiar and easy to digest. Practise the meal on your long runs first.

What should you eat after a run?

The AIS recommends a carbohydrate-rich snack or meal providing 1 to 1.2g of carbohydrate per kilogram of body weight within the first hour, especially if you will train again within 8 hours, with some protein. For a 70kg runner that is 70 to 84g of carbohydrate. If your next session is more than a day away, total daily intake matters more than timing.