The Ins and Outs of Carbohydrate Fueling

Carbohydrates are the primary fuel source for athletes during intense endurance exercise. Understanding the right amount of carbohydrate intake is crucial for optimal performance. Here's a detailed look at how much carbohydrate athletes need during different durations of exercise.

For exercises lasting less than one hour, athletes who are well-fueled typically don't need to worry about consuming carbohydrates during the activity. Their glycogen stores are sufficient to power the exercise. However, for high-intensity efforts lasting around 45-60 minutes, a small amount of carbohydrate ingestion or a carbohydrate-rich mouth rinse may offer some performance benefits.

As the duration increases to 1-2 hours, carbohydrate consumption becomes essential for maintaining performance. During this timeframe, it's beneficial to consume 30-90 grams of simple carbohydrates per hour. The harder the workout and the longer the duration within this range, the more appropriate it is to aim for the higher end of the intake range, around 60 grams per hour.

For exercise lasting more than two hours, athletes can benefit from higher carbohydrate intakes of 60 to 90 grams per hour, as long as it doesn't cause digestive issues. Elite athletes competing in long-distance events, such as Tour de France riders and Ironman winners, routinely report consuming high levels of carbohydrates per hour to fuel their performance.

Consuming 90 grams of carbohydrates per hour or more is not something that all athletes can achieve immediately. It may take time to "train the gut" and gradually build up to these high rates of consumption, especially for those prone to gastrointestinal issues.

At very high carbohydrate intake rates, such as 90 grams per hour or more, using a mixture of different carbohydrate sources, like glucose and fructose, can help maximize absorption through the gut. This approach is known as "multiple transportable carbohydrates" (MTCs).

While 90 grams per hour was once considered a firm ceiling for carbohydrate intake, there is now a growing trend among elite athletes to consume even higher doses during prolonged, intense exercise. However, for most athletes, even approaching 90 grams per hour is an impressive amount of fuel to absorb.

It's worth noting that during ultra-endurance events lasting six hours or more, additional considerations come into play, such as the benefits of consuming some fat and protein from real foods, as well as addressing potential taste fatigue from relying on a single fuel source.

Body size is generally not a major factor in determining carbohydrate intake rates during exercise. While it might seem intuitive that larger athletes would require more carbohydrates, research suggests that the limiting factor is the rate at which carbohydrates can be absorbed through the gastrointestinal tract, which is similar across different body sizes.

The optimal carbohydrate intake can vary from athlete to athlete due to individual differences in gut microbiomes and absorption rates. However, the general guidelines of 30-60 grams per hour for 1-2 hour exercise and 60-90 grams per hour for longer durations provide a solid starting point.

If you’re training for longer events, practice of the amount of carbohydrates you want to use in the race should be practiced in shorter duration sessions. Ie. Taking 75g of carbohydrates per hour in your bike rides of 1-2 hours is recommended ideal for practice for race nutrition and races that are 2+ hours. The more you practice, the better off your race will be.

Mastering your carbohydrate fueling is essential for reaching your full potential as an endurance athlete. The FuelMyMetrics Diary and App empowers you to do just that, providing personalized recommendations and insights to help you fuel for peak performance.

Ultimately, athletes should focus on finding the right carbohydrate intake that works for their individual needs, sport, and exercise duration. Experimenting with different sources and amounts of carbohydrates during training sessions can help identify the optimal fueling strategy for peak performance.

Don't let suboptimal fueling hold you back. Embrace the power of data and take control of your fueling strategy with the FuelMyMetrics Diary and App. Experiment, refine, and find the perfect balance of carbohydrates to propel you towards your goals. The path to success starts with fueling your body right, and FuelMyMetrics is your ultimate ally in that journey.  FUELMYMETRICS APP


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