Training and Racing Nutrition: Fuel Requirements for the Endurance Athlete

January 26, 2024

When it comes to achieving optimal health, endurance, and longevity in sports, focusing on nutrition is paramount. Proper nutrition is a vital element in realizing your full potential as an endurance athlete. If you do not eat according to your goals, how can you expect to achieve them?

In a previous article, we discussed what you need in your daily diet in terms of macronutrients, carbohydrate (CHO), protein and fat. We also discussed what to aim for from a more general and mindful approach to nutrition. In this article, we will dive into the specific nutrition recommendations before, during and after exercise to fuel your body appropriately, maximize gains from your training, perform your best on race day and enhance recovery.

Before we get started on the specifics, it is important to note for exercise sessions lasting 60-75 minutes or less, you typically do not need any fuel replacement. Always rehydrate with water, but supplementing with nutrition is not necessary.


  • The goal here is to increase blood glucose levels to spare muscle glycogen, “top off the tank.”
  • 3 hours prior to exercise: consume 3-5 g CHO / kg body weight
  • One hour prior to exercise: consume 1-2 g CHO / kg body weight


  • Consume 30-60 g carbohydrate (CHO) / hr in either liquid, solid or gel form.
  • To list a few examples, two gels, 6 shot bloks or two packs of sports beans meets this requirement.
  • Drinking 16 oz of sports drink (Tailwind, Gatorade) over the course of 60 minutes also meets this requirement.
  • There is little evidence to suggest CHO + PRO during exercise show any performance improvements. For events in the 70.3 distance or greater, the addition of protein and fat may be helpful to sustain a full feeling, help with boredom and gastrointestinal issues


  • Within 30 minutes of exercise: consume 1 g CHO / kg body weight and 0.4 g PRO / kg body weight, repeat this every two hours until a full meal can be consumed.
  • Timing of nutrition is important, particularly when you have two training sessions per day. For brick workouts, follow the instructions above for "during exercise." When you have two workouts split between your day, consider the following:
  • For less than 20 hours between training sessions / competitions, CHO consumption should occur immediately post-exercise. The muscles are more receptive to storing glycogen post-exercise. Specifically, consuming CHO immediately post-exercise, 1.5 g CHO/kg body weight, will show an improved rate of muscle glycogen re-synthesis over the first 4 hours after exercise.
  • For 20+ hours between training sessions / competition, consuming adequate CHO over this 20-hour time frame will sufficiently replenish muscle glycogen stores.

Consistently practice your nutrition during training so you are completely confident in both what you are fueling with and when you are taking in that fuel. Often, it takes many attempts testing various types and brands of fuel (gels, shot blocks, chomps, sports beans, CHO replacement drinks, honey stingers, clif bars, etc) to find what works best for you. What works for one person will not necessarily work for the next. Even those who have been racing for years find new products or foods that continue to work better for them.

For multi-sport athletes, understand the fuel you choose for the bike may look different than what you use on the run. The body can handle heavier items on the bike (like clif bars or even real food like baby potatoes or uncrustables), but this is generally not the case for the run. The exception here would be ultrarunning. The fuel you choose may also look different depending on what distance and type of event you are completing. For example, your preferred fuel for a sprint tri will likely be different than that of a 70.3 which may be different than that of a marathon.

Practice, practice and practice some more. Now is the time to practice, not one week, two weeks or even three weeks prior to race day. Your fuel will likely be a combination of your preferred CHO supplement (gels, shot bloks, etc), plus sports drink and water, depending on the type of event. It's important to find the right balance of what you ingest and when. Feeling confident you will not experience GI distress provides for a better performance and experience.

Also consider what you will wear on race day and where you will store your hydration and fuel sources as you bike and run. Test out a variety of solutions and find what works best for you. Practicing these details in advance is essential.

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