Triathlon Nutrition Basics: Carbs in g/kg and g/h
You swim, bike, and run, and you wonder how much to eat, and when. Official guidelines give precise numbers, in grams per kilo and per hour, which are more useful than plate percentages.
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The short answer
For triathlon nutrition, daily carbs scale with your training load: 5 to 7 g/kg for about 1 hour a day, 6 to 10 g/kg for 1 to 3 hours, and 8 to 12 g/kg beyond 4 to 5 hours, plus 1.2 to 2.0 g/kg of protein. During exercise, the American College of Sports Medicine recommends 30 to 60 g/h between 1 and 2.5 hours, and up to 90 g/h beyond that. Test these doses in training, never on race day.
Key takeaways
- Day to day, your carb needs rise with your training load: multiply your body weight by the g/kg that matches your training hours.
- Protein falls between 1.2 and 2.0 g/kg per day, spread across the day.
- Products that mix glucose and fructose let you use more carbs when you reach 90 g/h, a benchmark for efforts longer than 2.5 hours.
- Eating too little for your training volume has a name, REDs, and it affects your health as much as your performance.
A triathlon is three sports but one fuel tank. What you eat the night before, in the morning, on the bike, and during the run all belong to the same plan.
Official guidelines think in grams per kilo of body weight per day, then in grams per hour of effort, rather than in percentages of your plate. The examples below are for a 70 kg person.
Day to day: carbs scale with your training load
Your carb needs rise with your training volume. The joint position of the American College of Sports Medicine, the Academy of Nutrition and Dietetics, and Dietitians of Canada, published in 2016, gives these ranges:
| Training load | Carbs per day | Example for 70 kg |
|---|---|---|
| About 1 hour a day | 5 to 7 g/kg | 350 to 490 g |
| 1 to 3 hours a day, moderate to hard | 6 to 10 g/kg | 420 to 700 g |
| More than 4 to 5 hours a day | 8 to 12 g/kg | 560 to 840 g |
On the European side, the working group of the German Nutrition Society (DGE) uses the same benchmarks: 5 to 7 g/kg per day for moderate effort.
For protein, the same position puts the needs of endurance athletes between 1.2 and 2.0 g/kg per day, or 84 to 140 g for 70 kg, spread across the day.
Eat enough for what you burn
A triathlete who trains a lot can eat too little without noticing. The International Olympic Committee calls this REDs.
The 2023 consensus describes it as a continuum: a mild, short-lived energy shortfall stays “adaptable,” but it becomes “problematic” when it lasts, with various negative effects on performance.
Before and during the race
Before an effort longer than 60 minutes, the official position recommends 1 to 4 g of carbs per kilo, eaten 1 to 4 hours before. For 70 kg, that means 70 to 280 g: a wide range, to fine-tune in training.
For example, a 5.5-hour triathlon falls in the range beyond 2.5 hours. The top of the range, 90 g/h, comes to about 495 g of carbs in total, and 60 g/h comes to about 330 g.
At these high amounts, the type of carb matters. Products that mix glucose and fructose let you absorb more of the carbs you take in than products that contain only one of them.
To estimate how long your triathlon will take, and so your carb target per hour, the calculator gives you a race time based on your paces:
Free calculatorTriathlon timeOpen the calculator →Should you aim for 120 g/h?
The 2016 ACSM and 2019 DGE positions stop at 90 g/h. The 2026 UCI Sports Nutrition Project goes up to 90 to 120 g/h for a 5.5-hour grand tour stage on the road: a professional cycling setting, not to copy as is for amateur triathlon.
A 2026 randomized trial of 12 trained men compared two carb doses. After a heavy-intensity effort, the recommended dose improved a 4 km (2.5 mi) time trial compared with placebo (8.3 vs 8.6 min), but the higher dose did not. After a moderate effort, there was no difference. More is not always better.
Going higher without testing it risks a stomach that rebels. Master 60 to 90 g/h first.
Train your gut
Race day is not the time to discover your fueling plan.
In a 2017 study, runners took carbs repeatedly during their workouts for two weeks. Their digestive symptoms dropped by about 60%, and their performance on a distance test improved by 4 to 5%, while it dropped 2.1% with the placebo. This study looked at runners. The steps suggested below come from coaching practice.
What you can do at your next workout
- Multiply your weight by the g/kg for your training load to find your daily carb range.
- On any session longer than 1 hour, take 30 g of carbs per hour with a glucose and fructose product, then note the time, the amount, and how your stomach reacts.
- Move up a step at the next session (60 g/h, then up to 90 g/h on sessions longer than 2.5 hours) only if your stomach stayed calm, with no nausea. Otherwise, stay at the same step or go back, without forcing it.
- Repeat your pre-race meal during a long workout, within the 1 to 4 g/kg range, 1 to 4 hours before the start.
To read the data from a long session, see long session: how to tell if your fueling worked.
ELYO reads your workouts from your watch: you find the pace and heart rate of the session where you tested your dose, and you can compare one session to the next.
Frequently asked questions
How many carbs per hour in a triathlon?
Between 1 and 2.5 hours, the official position gives 30 to 60 g/h. Beyond 2.5 to 3 hours, it rises to 90 g/h with glucose and fructose blends. Test these doses in training.
Should I aim for 120 g/h like the pros?
The 2016 ACSM and 2019 DGE positions stop at 90 g/h. The 2026 UCI project goes to 90 to 120 g/h only for a grand tour road stage. A 2026 study found no benefit from the higher dose over the recommended one, so master 60 to 90 g/h first.
Can I train my stomach to handle more carbs?
A study on runners measured about a 60% drop in digestive symptoms after two weeks of repeated carb intake during exercise. Start low and build up in steps, and stay at the previous step if your stomach protests.
How do I know if I'm eating enough for my training load?
The g/kg ranges here only cover carbs. They do not measure your total energy intake. If you feel exhausted for a long time, talk to a doctor or a sports dietitian, who can look for the cause.
Sources
- Thomas D. T., Erdman K. A., Burke L. M. (2016). American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise. DOI
- Arbeitsgruppe Sporternährung der Deutschen Gesellschaft für Ernährung (2019). Position statement of the working group sports nutrition of the German Nutrition Society (DGE). Ernährungs Umschau. PDF
- UCI Sports Nutrition Project (2026). Race Nutrition for Road Cycling. International Journal of Sport Nutrition and Exercise Metabolism. Link
- Costa R. J. S., Miall A., Khoo A. et al. (2017). Gut-training: the impact of two weeks repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance. Applied Physiology, Nutrition, and Metabolism. DOI
- Fleitas-Paniagua P. R., Rasica L., de Almeida Azevedo R., Iannetta D., Alvares T. S., Zagatto A. M., Murias J. M. (2026). Recommended but Not High Carbohydrate Dose Improves Performance After Heavy- but Not Moderate-Intensity Exercise in Recreationally Trained Participants. Scandinavian Journal of Medicine & Science in Sports. DOI
- Mountjoy M. et al. (2023). 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine. DOI
Written with the help of AI.
