Goal
Fuelling endurance training
Carbohydrate is the main fuel for hard running and cycling. How much to eat day to day, before a long session, during it and afterwards.
Match carbohydrate to the training
The joint position of the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine scales carbohydrate to training load: 3–5 g per kg of body weight a day for light or skill-based activity, 5–7 g for about an hour of moderate exercise, 6–10 g for one to three hours, and 8–12 g for more than four to five hours.
For a 70 kg runner training an hour a day that is roughly 350–490 g. Needs change from day to day, so eat more around hard and long sessions and less on rest days instead of holding one fixed number all week. The percentage split above is only a rough translation of these gram targets.
Before and during
Before sessions longer than an hour, the guidance is 1–4 g of carbohydrate per kg, eaten one to four hours beforehand. Choose foods you know sit well: meals high in fat, protein or fibre are more likely to cause stomach trouble during the event.
Sessions under 45 minutes need nothing extra. For 1–2.5 hours, aim for 30–60 g of carbohydrate an hour from drinks, gels or ordinary food. Beyond about 2.5 hours, up to 90 g an hour can help, using products that mix glucose and fructose. Practise this in training, not on race day.
Recovery and race week
With a day or more between sessions, normal meals that meet your daily target are enough. If you train again within eight hours, 1–1.2 g of carbohydrate per kg an hour for the first four hours speeds refuelling. Around 20–40 g of protein after exercise supports muscle repair.
For events longer than 90 minutes, carbohydrate loading means 10–12 g per kg a day for the 36–48 hours beforehand. On fluids, the same position paper advises keeping losses under 2% of body weight, since larger deficits can impair endurance performance, particularly in hot weather.
Worth knowing
- These targets are for adults who train regularly for endurance. A few easy sessions a week do not call for sports drinks, gels or carbohydrate loading.
- If you have diabetes or take glucose-lowering medication, speak to your clinician before changing your carbohydrate intake around exercise.
- High carbohydrate intakes during exercise can upset the stomach. Build up gradually in training.
Common questions
Do I need gels, or will normal food do?
Either works. The target is grams of carbohydrate an hour, and the position paper counts everyday foods as well as sports products. Gels are simply easier to carry and swallow at speed.
Should I train fasted or low-carb to adapt better?
The evidence that “train-low” sessions improve performance in well-trained athletes is unclear. If you try them, keep them to easy sessions and fuel the hard ones properly.
How much protein do endurance athletes need?
The same joint position paper suggests 1.2–2.0 g per kg of body weight a day, spread across meals.
Sources
- Nutrition and Athletic Performance: joint position paper of Dietitians of Canada, the Academy of Nutrition and Dietetics and the American College of Sports Medicine (2016)
- Carbohydrates for training and competition, J Sports Sci (2011)
- International Society of Sports Nutrition position stand: nutrient timing (2017)
General information, not medical or dietary advice. Speak to a doctor or registered dietitian about your own situation.
