What to Eat Before, During and After Exercise

Few topics in sport generate as much confusion as workout nutrition. Eat before you train, or train fasted? Protein within 30 minutes, or whenever? Gels, bars, shakes, bananas? Every coach, influencer and supplement brand seems to have a different answer, usually delivered with total confidence.

The research is actually fairly settled on the big picture. The details depend on how long and how hard you train, what time of day it is and what you're trying to achieve. This guide walks through each stage (before, during and after exercise) and explains what to eat, how much and why. It leans mainly on the 2016 joint position statement from the American College of Sports Medicine, Dietitians of Canada and the Academy of Nutrition and Dietetics, and on position stands from the International Society of Sports Nutrition.

One principle sits above everything else: for most people, total daily intake matters more than precise timing. If you eat enough food overall, with enough carbohydrate and protein, timing becomes a way to fine-tune things rather than a make-or-break detail. Keep that in mind as you read. If a section feels like too much effort, skip it and get the basics right first.

Why workout nutrition matters

When you exercise hard, your muscles rely heavily on glycogen, the stored form of carbohydrate in your muscles and liver. You can only store a limited amount, typically enough for around 90 minutes of continuous hard effort. When glycogen runs low, intensity drops, everything feels harder and concentration slips. Marathoners call it hitting the wall. Footballers call it the last 20 minutes.

Training also causes small amounts of muscle damage and uses up fluid and electrolytes. Recovery means repairing those fibres, refilling glycogen and replacing what you sweated out. Food around training supports each job:

• Before: top up fuel stores so you can train at the intensity you planned.
• During: supply extra fuel and fluid for long or very hard sessions.
• After: provide protein for repair and carbohydrate to refill glycogen, especially if you train again soon.

Start with the daily picture

Before thinking about pre-workout snacks, it helps to know roughly how much carbohydrate and protein you need across a whole day. The guidelines scale carbohydrate with training load, which makes sense: someone doing a 30-minute gym session and someone riding four hours have very different fuel needs.

Most recreational athletes training an hour a day or less fall into the light to moderate bands. You don't need to weigh everything. As a rough guide, a fist-sized portion of rice, pasta or potatoes is around 40 to 50 g of carbohydrate, and a slice of bread is about 15 g.

For protein, the International Society of Sports Nutrition suggests 1.4 to 2.0 g per kg of body weight a day for most active people, spread across the day. For a 70 kg person, that's about 100 to 140 g. Most people hit this more easily than they expect once every meal includes a decent protein source.

The cost of not eating enough

Under-eating is a bigger problem among active people than most realise. The International Olympic Committee's 2023 consensus statement on Relative Energy Deficiency in Sport (REDs) describes how long-term low energy availability can affect hormones, bone health, immunity, mood and performance, in both women and men. Warning signs include missed or irregular periods, frequent illness, stress fractures, constant fatigue and performance that keeps dropping despite training.

If any of that sounds familiar, eating more is the first thing to try, and a sports doctor or dietitian is worth seeing. Cutting food further to "fix" a performance dip usually makes things worse.

Before exercise: fill the tank

What you eat before training depends mostly on how long you have before you start. As a general rule, the closer you are to exercise, the smaller and simpler the food should be. Fat, fibre and large amounts of protein slow digestion. That's fine at most meals but can cause stomach trouble when you're about to run or play.

How much carbohydrate before?

The guidelines suggest around 1 to 4 g of carbohydrate per kilogram of body weight in the one to four hours before exercise lasting longer than an hour. That's a deliberately wide range. Use the lower end for shorter or easier sessions and when you're eating close to the start, and the upper end for long, hard sessions with a full meal a few hours out.

For a 70 kg person, 1 g/kg is 70 g of carbohydrate, roughly a large bowl of porridge with a banana. At 4 g/kg it's 280 g, which suits a big pre-race meal three or four hours before a marathon or a long sportive.

Early-morning sessions

Lots of people train first thing and can't face a full breakfast. For easy sessions under an hour, training without food is generally fine. For harder or longer sessions, even a small amount of fast carbohydrate (20 to 30 g, about a banana or a glass of juice) can help. Your liver glycogen drops overnight, and that small top-up can make a noticeable difference to how intervals feel.

Drinking before you start

The ACSM guidance suggests drinking about 5 to 10 ml of fluid per kg of body weight in the two to four hours before exercise. For a 70 kg person that's roughly 350 to 700 ml, a large glass or two. It gives you time to absorb what you need and go to the toilet before you start.

Caffeine

Caffeine is one of the few supplements with strong evidence behind it. The International Society of Sports Nutrition's 2021 position stand found that doses of about 3 to 6 mg per kg of body weight, taken around 60 minutes before exercise, reliably improve performance in many types of sport. For a 70 kg person, 3 mg/kg is around 210 mg, roughly two cups of filter coffee.

More isn't better. Higher doses raise the risk of jitters, stomach trouble and poor sleep, and they don't seem to add much benefit. If you train in the evening, think about whether the caffeine will still be in your system at bedtime. If nerves are an issue for you, see our pre-game nerves guide, because caffeine can make them worse.

During exercise: only when it pays off

For most training sessions under an hour you don't need anything except water, and often not even that if you're well hydrated beforehand. Your stored glycogen is enough.

Fuel during exercise becomes useful as sessions get longer. Research led by Asker Jeukendrup has shaped the current guidance:

To put those numbers in context: a typical energy gel has about 20 to 25 g of carbohydrate, a medium banana about 25 g, and 500 ml of a standard sports drink roughly 30 g.

The mouth-rinse finding is one of the odder ones in sports science. Swilling a carbohydrate drink around your mouth and spitting it out seems to improve performance in hard efforts of about an hour, probably because receptors in the mouth signal to the brain that fuel is on the way. Useful if your stomach won't tolerate much during a hard session.

Hydration during exercise

For most people in most conditions, drinking to thirst works well. In long sessions or hot weather it helps to have a plan. Current guidance suggests keeping body weight loss during exercise under about 2%.

Avoid the opposite mistake too. Drinking far more than you sweat, especially plain water over many hours, can dilute your blood sodium to dangerous levels, a condition called hyponatraemia. If you finish a long event heavier than you started, you drank too much.

In sessions over two hours or when you sweat heavily, getting some sodium from sports drinks, electrolyte tablets or salty snacks helps you hold on to fluid and replace what you lose.

How to work out your sweat rate

This is worth doing once in warm weather and once in cool weather. It takes no special equipment.

1. Weigh yourself in minimal clothing, after going to the toilet, just before a one-hour session.
2. Train as normal. Note how much you drink.
3. Towel off and weigh yourself again in the same clothing.
4. Sweat rate (litres per hour) = weight lost in kg + litres drunk.

For example: you lose 1.0 kg and drank 0.5 litres in an hour, so your sweat rate is about 1.5 litres an hour. That tells you roughly how much you could aim to replace on longer days. Most people can't comfortably drink that much while moving, and that's fine. The aim is to limit losses, not to replace every drop.

After exercise: repair and refill

Recovery nutrition has two main jobs: providing protein so your muscles can repair and adapt, and replacing the carbohydrate you burned. How urgent it is depends on when you'll train next.

Protein

The International Society of Sports Nutrition recommends about 20 to 40 g of high-quality protein per meal for most people, roughly 0.25 to 0.4 g per kg of body weight. After training, a meal or snack containing that amount supports muscle repair and growth.

Good sources include:

• Chicken, fish or lean meat (around 25 to 30 g of protein in a 100 to 120 g serving)
• Greek yoghurt (about 15 to 20 g in a 200 g pot)
• Eggs (about 6 g each)
• Milk (about 8 g per 250 ml glass). Chocolate milk is a popular recovery drink, and it's a reasonable one.
• Lentils, beans and chickpeas (about 15 to 18 g per cooked cup)
• Tofu and tempeh
• Protein powder, if it's convenient

Carbohydrate

If you have a full day or more before your next hard session, your normal meals will refill glycogen without special effort. If you're training again within 24 hours, and especially if you train twice in a day, carbohydrate after training matters more. In that situation the guidelines suggest around 1 to 1.2 g per kg per hour for the first four hours, ideally with some protein too.

Fluid

If you've lost a lot of fluid, aim to drink around 1.25 to 1.5 litres for every kilogram lost over the following few hours, along with some salt from food or drinks. You need more than you lost because you keep losing fluid through urine while you rehydrate.

The "anabolic window"

You may have heard that you must eat protein within 30 minutes of training or lose the benefit. That idea has been relaxed considerably. A 2013 meta-analysis by Brad Schoenfeld, Alan Aragon and James Krieger found that once total daily protein was accounted for, protein timing around training had little effect on strength or muscle gains.

A sensible approach is to have a meal or snack with protein within a couple of hours after training. If you trained on an empty stomach, it makes more sense to eat sooner.

Protein before bed

The ISSN also notes that 30 to 40 g of casein protein (found in milk, cottage cheese and Greek yoghurt) before sleep can support overnight muscle repair. It's a nice extra for people trying to build muscle, not something you need to worry about otherwise. A bowl of Greek yoghurt before bed does the job.

Match day and race day

Competition days follow the same rules, with less room for experiments. A few extra points:

• Carb loading. For events longer than about 90 minutes (marathons, long rides, triathlons), eating around 10 to 12 g of carbohydrate per kg per day for the 36 to 48 hours before helps fill glycogen stores. That's a lot of food. Cutting back on fibre makes it easier on the stomach.
• Shorter events. For a 5 km, a football match or a 90-minute game, normal eating plus a good carbohydrate-based meal three to four hours before is enough. No loading needed.
• Tournaments and multi-game days. Pack more food than you think you'll need. Between games, eat easily digested carbohydrate and sip fluid. Sandwiches, bananas, rice cakes, yoghurt and sports drinks all travel well.
• Nothing new. Race day isn't the time to test a new gel or a new breakfast. Rehearse your whole routine before a long training session first.

Sample days for different schedules

Here's how it all fits together in a normal day. Adjust portions to your size and how hard you're training.

Morning session (7 am, hard intervals)

• 6:15 am: banana and a glass of water, or toast with honey
• 8:15 am: porridge made with milk, topped with Greek yoghurt and berries
• Lunch: wholegrain wrap with chicken or falafel, salad and hummus
• Dinner: salmon or tofu, rice and roasted vegetables

Evening session (6 pm, gym or team training)

• Breakfast and lunch: normal meals, each with protein
• 3:30 to 4 pm: yoghurt with granola and fruit, or a peanut butter and jam sandwich
• 7:30 pm: dinner with protein, carbohydrate and vegetables, such as chilli con carne with rice

Long weekend session (2 to 3 hours)

• 3 hours before: bagels with jam, a little yoghurt, juice
• During: 30 to 60 g of carbohydrate an hour from a sports drink, gels or bananas; water to thirst; some salt if it's hot
• After: eggs on toast with fruit, or a smoothie with milk, banana and oats, then a normal lunch

Rest day

• Normal meals with a bit less carbohydrate than training days, but don't slash it.
• Keep protein steady across the day.
• Plenty of fruit and vegetables. Rest days are a good time to catch up on the fibre you skip before sessions.

Vegetarian and vegan athletes

Plant-based athletes can meet every target in this guide. A few things take a bit more planning:

• Protein. Plant proteins tend to have a little less leucine, the amino acid that switches on muscle repair. Aim for the upper end of the per-meal range (closer to 40 g) and mix sources such as soy, lentils, beans, grains, nuts and seeds.
• Iron. Plant iron is less easily absorbed. Eat it with vitamin C (citrus, peppers, tomatoes) and keep tea and coffee away from iron-rich meals. Get your levels checked if you're always tired.
• Vitamin B12. Vegans need a reliable source, usually a supplement or fortified foods.
• Volume. High-fibre plant diets can be very filling, which makes it easy to under-eat on heavy training days. Include some lower-fibre carbohydrate such as white rice, pasta or bread around sessions.

Common workout nutrition mistakes

• Under-fuelling hard days. Trying to lose weight by skipping food around hard sessions usually costs performance and recovery. Keep carbohydrate around your hardest training.
• Over-fuelling easy days. A 30-minute walk doesn't need a recovery shake and an energy bar.
• Trying something new on race day. New gels, breakfasts and drinks cause a lot of race-day stomach trouble. Practise everything in training first.
• Ignoring total protein. One big shake after training doesn't fix a day that's otherwise low in protein. Spread it out.
• Forgetting fluids in the cold. You still sweat in winter, and thirst can be dulled. Keep drinking on long cold sessions.
• Relying on supplements. Most have weak evidence. Caffeine and creatine are notable exceptions, but neither fixes a poor diet.

The simple version

If you only remember one thing, make it this: eat enough, put carbohydrate around hard sessions, get protein at every meal and drink to thirst. Everything else in this guide refines that basic plan for longer sessions, early mornings and big events.

Start with one change this week. If you usually train hungry, try a small snack 45 minutes before your hardest session and notice how it feels. Small changes you actually keep will do more for your training than any supplement. And if you're building an aerobic base at the same time, our Zone 2 training guide explains how to structure the sessions you're fuelling.

Frequently asked questions

Sources and further reading

1. Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement: Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise, 2016;48(3):543-568.
2. Kerksick CM, et al. International Society of Sports Nutrition position stand: nutrient timing. Journal of the International Society of Sports Nutrition, 2017;14:33.
3. Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition, 2017;14:20.
4. Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 2014;44(Suppl 1):S25-S33.
5. Schoenfeld BJ, Aragon AA, Krieger JW. The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. Journal of the International Society of Sports Nutrition, 2013;10:53.
6. Guest NS, et al. International Society of Sports Nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition, 2021;18:1.
7. Mountjoy M, et al. 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine, 2023;57(17):1073-1097.