Why what you eat beforehand matters
Your muscles and liver store carbs as glycogen, and it is the main fuel when you train hard. Overnight your liver uses up a good part of its store, so the meal in the hours before training helps refill it (Thomas et al., 2016).
How much it matters depends on how long you train. A review with a meta-analysis of 46 studies found that eating beforehand improves performance in long aerobic efforts, but not in short ones (Aird et al., 2018). If your session is short, what you eat beforehand matters less than what you eat across the whole day.
How much to eat and when
The American College of Sports Medicine joint position recommends 1 to 4 g of carbs per kilo of body weight, eaten 1 to 4 hours before exercise lasting more than 60 minutes (Thomas et al., 2016). For protein, the International Society of Sports Nutrition (ISSN) points to doses of 20 to 40 g, or 0.25 to 0.40 g per kilo, spread every 3 to 4 hours through the day (Kerksick et al., 2017).
| When | What to eat | Examples |
|---|---|---|
| 3 to 4 hours before | A full meal: plenty of carbs, moderate protein, little fat | Rice or pasta with chicken and cooked vegetables |
| 1 to 2 hours before | Something smaller: easy-to-digest carbs and a bit of protein | Oatmeal with milk, or yogurt with fruit, toast with cottage cheese |
| Under 1 hour before | Only fast carbs, in a small amount, or a drink | A banana, rice cakes, a shake |
The less time you have left, the smaller and simpler the meal should be, so you do not start on a full stomach.
How to work out your meal in 3 steps
- Check how long until you train. With 3 or 4 hours to go, you can have a full meal. With 1 hour to go, stay at the low end of the range.
- Work out the carbs. Multiply your weight in kilos by 1 (little time left) and up to 4 (plenty of time and a long session). For 70 kg, that is 70 to 280 g.
- Add the protein. Multiply your weight in kilos by 0.25 and by 0.40. For 70 kg, that is about 18 to 28 g. For the rest of the day, the protein calculator gives you your target.
To see how that meal fits into the rest of your day, use the macro calculator.
Which foods to choose and which to avoid
- Carbs as the base. Rice, pasta, bread, oats, potatoes or fruit. They refill the glycogen you are about to burn.
- Moderate protein. Eggs, dairy, chicken or fish, without a huge serving if your session is close.
- Little fat and fiber. They digest slowly. Meals low in fat, low in fiber and low to moderate in protein are the least likely to upset your stomach (Thomas et al., 2016).
- A drink if you are nervous or short on time. A shake or smoothie digests faster than a solid meal, and helps when nerves or your schedule get in the way of eating properly.
Test your meals on regular training days before using them on an important one. Every stomach handles food differently.
What if I train fasted?
Training without eating will not ruin your results. In a meta-analysis of more than 20 trials, eating protein right before or after training did not change strength or muscle gained once total daily protein was accounted for, and that total was what mattered most (Schoenfeld et al., 2013).
What does change is performance in long sessions: eating beforehand helps there (Aird et al., 2018). If you train early and fasted, make sure you eat well afterwards and hit your protein target for the day. See how much you need in the guide to daily protein.
Water and coffee before a workout
- Drink 5 to 10 ml of water per kilo, 2 to 4 hours before. For 70 kg that is about 350 to 700 ml (12 to 24 oz). The goal is pale yellow urine, with time to use the bathroom before you start (Thomas et al., 2016).
- Coffee helps, at the right dose. Caffeine improves performance at 3 to 6 mg per kilo, usually taken about 60 minutes before. For 70 kg that is 210 to 420 mg. Very high doses, such as 9 mg per kilo, bring more side effects without better performance (Guest et al., 2021).
- Mind your sleep. If you train at night, caffeine can cost you sleep, and it causes anxiety in some people (Guest et al., 2021).
Questions
How long before a workout should I eat?
1 to 4 hours before. With 3 or 4 hours you can have a full meal; with 1 hour or less, pick something small and high in carbs, like a piece of fruit (Thomas et al., 2016).
What should I eat before a workout to build muscle?
Carbs plus about 20 to 40 g of protein in the meal before are a good base (Kerksick et al., 2017). But for building muscle, hitting your daily protein and calories matters more than exact timing. See the [muscle building routines](lista:ganar-masa-muscular).
Is it bad to work out on an empty stomach?
No, as long as you eat well afterwards and reach your daily protein. In short sessions performance is similar; in long ones, eating beforehand helps (Aird et al., 2018).
What should I eat 30 minutes before a workout?
Something small and easy to digest, with carbs and little fat and fiber: a banana, a few rice cakes or a shake. A big meal that close tends to sit heavy.
Sources
- 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. doi:10.1249/MSS.0000000000000852
- 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. doi:10.1186/s12970-017-0189-4
- Aird TP, Davies RW, Carson BP. Effects of fasted vs fed-state exercise on performance and post-exercise metabolism: a systematic review and meta-analysis. Scand J Med Sci Sports. 2018;28(5):1476-1493. doi:10.1111/sms.13054
- Schoenfeld BJ, Aragon AA, Krieger JW. The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. J Int Soc Sports Nutr. 2013;10(1):53. doi:10.1186/1550-2783-10-53
- Guest NS, VanDusseldorp TA, Nelson MT, et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18(1):1. doi:10.1186/s12970-020-00383-4
This guide is for information only and does not replace advice from a health professional.
