The short answer
Before a run, eat a light, carbohydrate-based snack 1–2 hours beforehand, such as toast with honey, a banana or yoghurt and fruit. Then:
- during runs over about an hour, aim for 30–60 g of carbohydrate an hour;
- after a run, have carbohydrate plus 20–40 g of protein, and rehydrate;
- match your daily carbohydrate to how much you're training;
- practise your race-day food in training, never on the day.
Whether you're running to keep fit or training for a marathon, what you eat makes a big difference to how well you train and recover. As a dietitian and exercise scientist, here's what the evidence says about fuelling before, during and after your runs.
What should you eat before a run?
Your pre-run food should fuel and hydrate you, help you keep up the pace, stop hunger pangs and avoid gut upset.
When you run decides how much and when you eat. A full meal takes about 2–4 hours to digest. For early runs or morning races, it doesn't make sense to lose sleep for a big breakfast. Instead, have a light, carbohydrate-based snack 1–2 hours before to top up your glycogen (stored carbohydrate).
Lower-fibre, low-fat options are easiest on the stomach:
- toast or crumpets with jam or honey;
- a banana or a small bowl of cereal;
- yoghurt and fruit;
- a smoothie, if nerves make solid food hard.
Practise your race-day food
Test your pre-race breakfast and any gels or drinks on long training runs first. Never try something new on race day.
How much carbohydrate do runners need?
It depends on how much you train. As your distance goes up, so does your need for carbohydrate, the main fuel for endurance running. Sports nutrition guidelines set targets in grams per kilogram of body weight per day:1
- Light training: about 3–5 g/kg.
- Moderate training (about an hour a day): about 5–7 g/kg.
- Endurance training (1–3 hours a day): about 6–10 g/kg.
For a 70 kg runner doing moderate training, that's roughly 350–490 g a day, from foods like grains, bread, rice, pasta, potatoes, fruit, milk and yoghurt. Eat more on big training days and less on rest days.
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Find a sports nutrition practitioner →Should you eat during a run?
For runs under about an hour, most people don't need to. For longer or harder runs, aim for about 30–60 g of carbohydrate an hour, with fluid, starting early and topping up every 15–20 minutes.2 Sports drinks, gels, chews, jelly lollies or a banana all work. Practise in training so your gut gets used to it.
How do you stay hydrated and avoid cramps?
Drink regularly through the day and bring fluid on longer runs, especially in the heat. When you sweat, you lose fluid and electrolytes such as sodium, and heavy sweaters lose more. On runs over about an hour, a drink with electrolytes can help.
Cramps are common, but their causes aren't fully understood. Magnesium supplements are often marketed for cramps, but a Cochrane review found no trials testing them for exercise-related cramps.4 Gradually building your training, good fuelling and stretching are better places to start.
What should you eat after a run?
There's no single best recovery meal. Aim to refuel with carbohydrate, repair muscle with protein, and rehydrate.
- Protein: about 20–40 g after your run helps muscle repair.2 That's a tub of Greek yoghurt with muesli, a tuna sandwich, or eggs on toast.
- Carbohydrate: refills your glycogen. If you're training again within about 4 hours, eat carbohydrate early and often: about 1.2 g/kg an hour.2
- Fluid: drink to replace what you've sweated out.
Do you need to eat within 30 minutes? Only if your next session is soon. Otherwise, getting enough protein and carbohydrate across the day, with protein spread over meals every few hours, matters more than the exact timing.2
Do runners need antioxidant or other supplements?
Most don't. Running does increase free radicals, but these act as signals that help your body adapt to training. Research suggests high-dose antioxidant supplements, such as vitamins C and E, may blunt some of those training gains.3 Get your antioxidants from a colourful mix of fruit and vegetables instead. Oily fish like salmon, sardines and mackerel are also a good regular choice.
How do rest, sleep and tapering affect your running?
Rest days let your body repair and lower your injury risk, especially if you're new to running. Aim for 7–9 hours of good-quality sleep a night.6
During a taper, keep eating to your appetite and keep carbohydrate up before race day. A small weight gain is normal, because your muscles store more glycogen (and the water that comes with it).
Not eating enough for your training?
Regularly eating too little for the amount you train, whether on purpose or not, can lead to Relative Energy Deficiency in Sport (REDs). It's linked with bone stress injuries, missed or irregular periods, frequent illness and poorer performance, in both women and men.5 If this sounds familiar, or you're restricting food to stay light, talk to a sports dietitian.
Want a fuelling plan for your next race?
HealthBank practitioners who work in sports and performance nutrition can build a training and race-day plan around your body, your goals and your gut.
Find a sports nutrition practitioner →Frequently asked questions
What should I eat before a run?
A light, carbohydrate-based snack 1–2 hours before, such as toast with honey, a banana, or yoghurt and fruit. Keep it low in fibre and fat.
Is it OK to run on an empty stomach?
For short, easy runs, many people feel fine. For longer or harder sessions, eating carbohydrate beforehand helps you keep up the pace.
What should I eat after a run?
Combine carbohydrate with about 20–40 g of protein, such as Greek yoghurt with muesli or eggs on toast, and rehydrate.
Do I need to eat within 30 minutes of running?
Only if you're training again within a few hours. Otherwise, your total intake across the day matters more.
Does magnesium help with cramps from running?
There's no good evidence it does. A Cochrane review found no trials of magnesium for exercise-related cramps.
How many carbs do runners need?
About 5–7 g per kilogram of body weight a day for moderate training, and 6–10 g/kg for endurance training of 1–3 hours a day.
References
Research (PubMed)
- Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine joint position statement: nutrition and athletic performance. Med Sci Sports Exerc. 2016;48(3):543–568. PubMed 26891166
- Kerksick CM, Arent S, Schoenfeld BJ, et al. International Society of Sports Nutrition position stand: nutrient timing. J Int Soc Sports Nutr. 2017;14:33. PubMed 28919842
- Merry TL, Ristow M. Do antioxidant supplements interfere with skeletal muscle adaptation to exercise training? J Physiol. 2016;594(18):5135–5147. PubMed 26638792
- Garrison SR, Korownyk CS, Kolber MR, et al. Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev. 2020;9(9):CD009402. PubMed 32956536
- Mountjoy M, Ackerman KE, Bailey DM, et al. 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med. 2023;57(17):1073–1097. PubMed 37752011
Australian guidelines
- Australian Government Department of Health, Disability and Ageing. Physical activity and exercise guidelines: recommendations for adults (18 to 64 years). View source
This article is general information and isn't a substitute for personalised advice. Speak to your practitioner about your situation.
Robbie is a Sydney-based Accredited Practising Dietitian (APD) and Exercise Scientist with over 17 years of experience. He holds a Bachelor of Exercise Science (Nutrition) and a Master of Nutrition and Dietetics, and is the Director and Co-founder of HealthBank.