How many carbs per hour to take, how to train your gut, what to eat before a race, and how to carb-load. Fuelling trained as seriously as the running.
Updated August 2026 · Editorial and coach review in progress · 6 questions answered
For exercise lasting 1 to 2.5 hours, 30 to 60 g of carbohydrate an hour is a common range. During a marathon, many runners build toward 60 to 90 g an hour if it is rehearsed and tolerated. Intake above 90 g an hour remains emerging elite practice, not a general target. Drink to thirst or a rehearsed individual plan, and do not force fluid at every station or drink enough to gain body mass.
Practise the exact products and timing you expect to use, beginning with an intake you tolerate. Increase gradually across selected long runs, and step back if bloating, nausea or urgency persists. Rehearsal can improve tolerance, but it does not mean the gut will accept an unlimited dose.
A little personal, but high-carb and simple works well, something like white bread with honey. You want easy energy that sits well, not a big or rich meal.
Carbohydrate loading can increase glycogen availability before a marathon. Consensus guidance commonly uses about 8 to 12 g of carbohydrate per kg of body mass per day for roughly 36 to 48 hours, but the exact plan should fit body size, tolerance and normal diet. Rehearse the foods and discuss unusually high targets or gastrointestinal concerns with a sports dietitian.
Health first, always. Being healthy matters more than any number on a scale. Weight and body composition rarely move things as much as people assume, and chasing them is a road that goes bad fast. Put your attention on fuelling and eating enough to stay healthy. If weight is turning into a worry or a fixation, take that as the signal to get proper support rather than to start cutting.
Some experienced athletes use carefully planned low-carbohydrate sessions for a narrow training purpose, but the performance benefit is uncertain and the trade-offs can include poorer session quality, recovery and energy availability. It is not necessary for successful marathon training. Most runners are better served by fuelling key sessions, practising race intake and discussing any deliberate restriction with a sports dietitian.
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Professional position statement
Supports: Individual carbohydrate, fluid and recovery strategies should match event demands and be rehearsed.
Does not establish: Population ranges are not personal prescriptions and do not guarantee tolerance.
International consensus statement
Supports: Carbohydrate availability, race fuelling and gut training should be event-specific and individualised.
Does not establish: It does not support treating intake above 90 g per hour as a general marathon target.
International consensus statement
Supports: Avoiding overdrinking and exercise-associated weight gain reduces hyponatraemia risk.
Does not establish: Sodium intake does not make excessive fluid intake safe.
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