Carbohydrate Needs for Endurance Athletes: Grams per Kilogram by Training Load
October 21, 2026
Carbohydrate is the main fuel for moderate to high-intensity exercise, stored as glycogen in muscles and the liver in limited amounts (about 400 to 500 grams in total, or roughly 1,600 to 2,000 calories). Endurance athletes can deplete these stores in 90 minutes to 3 hours of hard exercise, so their daily needs are well above those of sedentary people, who do well on 3 to 5 g/kg of body weight or less from a general health perspective.
Consensus guidelines from sports nutrition organizations tie daily carbohydrate intake to training volume: about 3 to 5 g/kg for light activity (up to an hour a day), 5 to 7 g/kg for moderate training (about an hour), 6 to 10 g/kg for 1 to 3 hours of endurance exercise a day, and 8 to 12 g/kg for extreme programs of more than 4 to 5 hours daily.
Skip the math and get your answer instantly:
Open the Macro Calculator →Daily Targets by Training Load
Multiply your body weight in kilograms by the g/kg target. A 70 kg athlete training moderately for an hour a day needs about 350 to 490 g of carbohydrate, supplying 1,400 to 1,960 calories. During a heavy training block of 2 to 3 hours a day, the target of 8 to 10 g/kg is 560 to 700 g, 2,240 to 2,800 calories from carbohydrate alone. Total calorie needs also rise, so protein (1.2 to 2.0 g/kg) and fat (about 20% to 35% of calories) fill in the remainder.
| Training load | Carbohydrate (g/kg/day) | 70 kg athlete (g/day) | Calories from carbohydrate |
|---|---|---|---|
| Light (low intensity or skill) | 3 to 5 | 210 to 350 | 840 to 1,400 |
| Moderate (about 1 hour/day) | 5 to 7 | 350 to 490 | 1,400 to 1,960 |
| High (1 to 3 hours/day) | 6 to 10 | 420 to 700 | 1,680 to 2,800 |
| Very high (4 to 5+ hours/day) | 8 to 12 | 560 to 840 | 2,240 to 3,360 |
Fueling During Exercise
For sessions longer than about 60 to 75 minutes, taking in carbohydrate during exercise delays fatigue. Guidelines suggest 30 to 60 grams per hour for efforts of 1 to 2.5 hours, and up to 90 grams per hour for events longer than 2.5 to 3 hours, using multiple carbohydrate types (glucose plus fructose) to increase absorption. A gel contains about 20 to 25 grams, a sports drink about 14 grams per 8 ounces (240 mL), and a banana about 27 grams. A 3-hour ride at 60 grams per hour requires 180 grams: for example, three bottles of sports drink and four gels.
The gut can be trained to tolerate higher intakes by practicing in training. Do not try new products on race day.
Before and After Exercise
For races longer than 90 minutes, carbohydrate loading in the 1 to 3 days before can fill glycogen stores: 8 to 12 g/kg per day, which is 560 to 840 grams for a 70 kg athlete, with reduced fiber and fat for comfort. A pre-exercise meal 1 to 4 hours before with 1 to 4 g/kg of carbohydrate helps. After hard sessions, consuming 1.0 to 1.2 g/kg per hour for the first four hours speeds glycogen recovery when you have less than 8 hours before the next hard session. If you have a day or more, regular meals suffice.
Train Low? Periodizing Carbohydrate
Some athletes deliberately do certain sessions with low carbohydrate availability, such as easy morning runs fasted or the second workout of the day without refueling, to enhance fat oxidation and training adaptations, while consuming high carbohydrate for key hard sessions and races. This 'train low, compete high' approach is used selectively and carefully, since chronically low energy availability can impair performance, immunity, and bone health. It is not a license to under-eat.
Putting It Into Practice
Estimate your training load for the week, set your daily g/kg target, and spread carbohydrate through meals and snacks. Choose rice, pasta, potatoes, oats, bread, fruit, and sports products depending on timing. Monitor your energy, mood, sleep, and performance, and adjust. A registered sports dietitian can help tailor a plan, especially for athletes with medical conditions.
Frequently Asked Questions
How many carbs does an endurance athlete need?
From about 5 to 12 g per kg per day, depending on training volume.
How many carbs per hour during a long race?
About 30 to 60 g per hour for 1 to 2.5 hours, and up to 90 g per hour for longer events.
What is carb loading?
Increasing carbohydrate to 8 to 12 g/kg in the 1 to 3 days before a long event to maximize glycogen.
Is low-carb training good for endurance?
Selective low-carbohydrate sessions may help adaptation, but chronic restriction can harm performance.
How much glycogen can the body store?
About 400 to 500 g in muscle and liver in total.