Diets · 5 min read ·

Eating around training: what matters

The anabolic window, fasted cardio, running gels. What in sports nutrition is backed by studies — and what is just a detail.

In a nutshell

1Protein

Strong evidence — 49 studies 1.6 g/kg A summary of 49 randomised trials with 1,863 people: extra protein with strength training increased strength (one-repetition maximum by 2.5 kg) and fat-free mass (by 0.3 kg). Above about 1.6 g of protein per kilo of body weight a day, no more muscle was gained. The effect was larger in trained people and smaller with age.3
Expert recommendation 20–40 g The International Society of Sports Nutrition (ISSN): a dose of 20–40 g of high-quality protein (0.25–0.40 g per kilo) every 3–4 hours best supports muscle protein synthesis. But total daily intake is the priority.1

How much protein to eat and from which sources is covered in the article Protein.

2The anabolic window

Moderate evidence 23 studies A summary of 23 studies on muscle growth: once total protein intake was taken into account, timing protein right around training did not affect strength or muscle size.2

According to the ISSN, protein within two hours after training reliably raises muscle protein synthesis. If you ate shortly before training, the meal after it matters less.1

Before sleep, 30–40 g of casein (a milk protein found in large amounts in cottage cheese or quark) can raise muscle protein synthesis overnight.1

3Carbohydrates and endurance

Strong evidence — 136 studies 136 studies A summary of 136 studies: carbohydrates taken during endurance exercise improved performance compared with placebo and lowered perceived exertion.4
Expert recommendation 30–60 g/h ISSN: in intense exercise lasting more than an hour, take 30–60 g of carbohydrate per hour, for example as a 6–8% sports drink in small doses every 10–15 minutes.1

When the next session is less than 4 hours away, the ISSN recommends refuelling carbohydrates quickly (1.2 g per kilo per hour).1

4Fasted or fed?

Moderate evidence 46 studies A summary of 46 studies: eating before training improved performance in longer aerobic exercise, with no difference in shorter exercise. After fasted exercise there were more free fatty acids in the blood.5
Weak evidence — 5 small studies 96 people Five studies with 96 people: fasted morning exercise did not lead to more weight or fat loss than exercise after a meal. But there are few studies.6

What to take from this

Sources

Written on , based on studies available at that date. Newer research may change the conclusions.

  1. Kerksick C. M. et al. (2017). International Society of Sports Nutrition position stand: nutrient timing. J Int Soc Sports Nutr 14:33. doi.org/10.1186/s12970-017-0189-4
  2. Schoenfeld B. J., Aragon A. A., Krieger J. W. (2013). The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. J Int Soc Sports Nutr 10:53. doi.org/10.1186/1550-2783-10-53
  3. Morton R. W. et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med 52:376–384. doi.org/10.1136/bjsports-2017-097608
  4. Ramos-Campo D. J. et al. (2024). The ergogenic effects of acute carbohydrate feeding on endurance performance: a systematic review, meta-analysis and meta-regression. Crit Rev Food Sci Nutr 64:11196–11205. doi.org/10.1080/10408398.2023.2233633
  5. Aird T. P., Davies R. W., Carson B. P. (2018). Effects of fasted vs fed-state exercise on performance and post-exercise metabolism: a systematic review and meta-analysis. Scand J Med Sci Sports 28:1476–1493. doi.org/10.1111/sms.13054
  6. Hackett D., Hagstrom A. (2017). Effect of overnight fasted exercise on weight loss and body composition: a systematic review and meta-analysis. J Funct Morphol Kinesiol 2:43. doi.org/10.3390/jfmk2040043

This is general information and does not replace a doctor or a sports dietitian. If you have diabetes, ask a doctor about eating around training.