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What's in a fueling strategy?

You're doing all the training and have your race strategy planned out, but what about your fueling strategy? For any race longer than 75-90 minutes, this part is important.

When I plan a race fueling strategy, some of the factors I consider are race type, duration, course profile, environment (temperature, humidity, elevation), time of day, fitness, race goals, availability of on-course support, and even a female athlete's menstrual cycle phase in some cases. It's also important to consider the athlete's regular diet and fueling strategies implemented during training. Ideally, we would like to develop and refine the event strategy during training starting a few weeks prior to the event, at the latest.

At the core, a fueling strategy has three main components. It gets more complicated for multi-day races and ultra-endurance events. Here, I will focus on one-day events between 90 minutes and ~4-6 hours in duration.


Carbohydrate supplementation of ~30–90 grams per hour during prolonged exercise can delay fatigue and improve performance, with higher rates of intake and tolerance of intake being proportional to performance improvements. Some highly trained athletes are able to tolerate and improve performance with 90-120 grams per hour.

However, not all athletes are immediately able to tolerate high rates of carbohydrate intake during exercise, due to a variety of factors including heat or heat stress, fat or fiber content of food intake, type of carbohydrate ingested, dehydration, following a low-carbohydrate diet, and more. For this reason, I suggest athletes repeatedly practice race nutrition strategies using the specific products and amounts that are planning to be used during the event. Additionally, compared to a moderate carbohydrate diet, several weeks of a high carbohydrate diet appears to be supportive in handling higher rates of carbohydrate intake during exercise.


Dehydration is one of the most common factors leading to race-day issues like GI problems, fatigue, cramping, etc. Knowing your estimated sweat rate in race-like conditions is helpful to dial in your hydration plan; combining this with your sense of thirst can help you refine on race day. The warmer or more humid the ride, the more intense, and the higher the elevation, the more fluids you'll want to drink, as your sweat rate will be higher. 

Keep in mind that you don't need to replace 100% of the fluids you lose from sweating. If you are dehydrating by 2-3% during a 4 hour ride but your goal event is longer than 8 hours, you will likely need to increase the amount of fluids you are ingesting to avoid more severe dehydration. 


If you are generally replacing over 70% of your sweat losses with your hydration strategy, you tend to not drink enough, or your race is going to be warmer than the conditions you have been training in, you should consider hourly sodium intake as part of your fueling strategy through sports drinks, gels, and chews.  

Avoid very high concentrations (more than 1 gram of sodium per liter of fluid) of electrolyte beverages and salt tabs during an event. For reference, a serving Skratch hydration mix contains 800 milligram of sodium per liter, and a 16-ounce serving of Fluid Performance contains about 500 milligrams of sodium per liter. I recommend choosing a product that suits your taste preference and does not cause GI issues at your race intensity, during long rides, or in the heat. If you're combining gels and chews with your sports drink, make sure you account for the sodium content in those products as well.

Pay attention to your thirst and taste for salt. If you're thirsty for plain water or craving salty foods, listen to those signals. For example, if you are at aid station and a handful of salty chips or a cup of plain water is calling your name, that is probably what you need.

Bonus: Gut Training

The concept of gut training involves a more structured approach that has been proposed to improve the tolerance and the absorption of carbohydrates during exercise. Gut training refers to repeated intentional exposure to fluids and foods during exercise for two or more weeks that leads to the ability to increase nutrition intake, which in turn supports performance outcomes. Trained athletes who are accustomed to regular fuel intake during exercise may not see as many changes in gut-related outcomes compared to more recreational athletes or to those who do not regularly fuel training per the published recommendations.

A gut training protocol may look something like this:

  • For at least two weeks, complete an individualized protocol that includes about three or more days per week of gut training

  • During the sessions, find your limit of carb and fluid intake per hour using the actual products (food and drink) you would plan to use during the event. The limit would be when you start to experience upper or lower GI symptoms.

  • Consider some of the following factors that may influence your protocol: volume of fluid, concentration of fluid, frequency of intake, type of carbohydrate source, your regular diet (such as FODMAP content and amount of dietary carbohydrate), heat/humidity in environment, hydration status, fat/fiber content of your fueling plan etc.

Remember, having a plan that you have practiced is important, and so is trusting your gut feelings on race day! If you're having issues or need more guidance with creating your event-day plan, get in touch here or email me at


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