Many endurance athletes still treat race fueling as a simple calculation: buy a few gels, start taking them at a certain mile, and hope the plan works. That approach is increasingly outdated.
The current thinking is more practical: carbohydrate intake is a performance skill. Your body needs to become comfortable processing fuel while you run, ride or race. The target is not just something to reach on event day—it is something to practise during training.
The headline numbers have not changed—but their meaning has
For long endurance sessions, widely used sports-nutrition guidance still provides a useful starting point:
- For sessions lasting about 45–75 minutes, small amounts of carbohydrate may help, particularly when intensity is high.
- For sessions lasting one to two and a half hours, aim for roughly 30–60 grams of carbohydrate per hour.
- For efforts longer than two and a half hours, many athletes can work toward 60–90 grams per hour.
- Some well-trained athletes competing in long events may tolerate up to 90–120 grams per hour, but this requires careful practice and is not a universal target.
The important update is that these figures should not be treated as mandatory steps. A cyclist completing a four-hour steady ride may perform well on 60 grams per hour. A marathoner with a sensitive stomach may need to begin lower. An ultrarunner may need a combination of drinks, gels and solid food to make a higher intake realistic.
Why more carbohydrate can create problems
Carbohydrate absorption is not unlimited. If an athlete takes in more than the gut can move and absorb, the result may be bloating, sloshing, cramps or an urgent search for a bathroom. Increasing intake without training the digestive system often creates the exact problem the athlete is trying to prevent.
Different carbohydrates can also use different transport pathways in the intestine. That is why products combining glucose or maltodextrin with fructose are common in endurance nutrition. The combination can allow a higher total intake than relying on one carbohydrate source alone—but it does not remove the need for gradual practice.
Fluid volume, intensity, heat, body size and the concentration of the drink all affect tolerance. A fuel plan that works on a cool two-hour ride may fail during a hot marathon effort when the athlete is drinking less or running at a higher intensity.
Gut training belongs in the weekly plan
Start with the amount you already tolerate, then increase slowly. For example, a runner currently taking one 25-gram gel during a 90-minute long run could try 35–40 grams per hour for two or three sessions before progressing further.
Keep the experiment controlled. Change one variable at a time, such as total carbohydrate, product type or drink concentration. If you change all three at once, you will not know what caused a stomach issue—or what solved it.
A simple four-week progression
- Week one: Use 30–40 grams per hour on one long or demanding session.
- Week two: Repeat the same intake and focus on timing it consistently, such as taking fuel every 20 minutes.
- Week three: Increase by approximately 10–15 grams per hour if digestion has been comfortable.
- Week four: Test the intended race intake during a session that matches the event’s pace, duration and terrain as closely as possible.
This progression is only a framework. Athletes with a history of gastrointestinal problems, diabetes or other medical conditions should seek individual advice from a qualified sports dietitian or healthcare professional.
Timing matters as much as the hourly total
A target of 60 grams per hour is easier to tolerate when divided into regular doses than when consumed in one large serving. That could mean a 30-gram gel every 30 minutes, or smaller amounts every 15–20 minutes.
Starting early is also important. Waiting until fatigue, hunger or dizziness appears usually means the athlete is already behind. For a long race, begin taking carbohydrate during the first 20–30 minutes rather than treating fuel as an emergency response.
Before training or racing, many athletes benefit from a carbohydrate-rich meal or snack. General guidance often falls between 1 and 4 grams per kilogram of body mass in the one to four hours before exercise, with the lower end more practical when there is less time or the athlete is prone to stomach discomfort. The right amount depends on the session, personal tolerance and the time available for digestion.
Do not confuse carbohydrate with hydration
Fuel and fluid solve different problems. A sports drink may provide both, but drinking more does not automatically compensate for too little carbohydrate, and taking more gels does not replace fluid lost through sweat.
Sodium needs are similarly individual. Sweat rate, weather, exercise duration and the saltiness of an athlete’s sweat all matter. Avoid turning a single sodium number into a rule for every session. Instead, monitor thirst, body weight changes, urine patterns and symptoms across different conditions. Extreme overdrinking can be dangerous, so “more” is not always better.
Build a race plan you can actually execute
Write the plan in terms of products and timing, not just grams. “Consume 75 grams per hour” is less useful than “take one 25-gram gel at 20, 40 and 60 minutes, with water as needed.” A specific plan is easier to remember when the course becomes difficult.
- Record the carbohydrate content of every gel, drink or food item.
- Check whether products contain caffeine and decide in advance how much you want.
- Practise opening packaging while moving.
- Match drink concentration and fuel timing to the aid stations or bottle capacity available on race day.
- Keep a backup option for a product that becomes unappealing or unavailable.
After each long session, note your intake, pace, weather, stomach comfort and energy levels. The goal is not to create a perfect spreadsheet. It is to identify a repeatable plan that supports performance without making the gut the limiting factor.
The takeaway for your next training block
The latest endurance-fueling message is not simply to consume more. It is to fuel deliberately, practise regularly and choose an intake that matches the event and your own tolerance.
Start with a manageable amount, take it consistently, and build gradually. By race day, your nutrition should feel like part of your pacing strategy—not a last-minute experiment.
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