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  • Writer's pictureBrooke Evans

Fueling for Performance: Eating Strategies for Runners & Other Athletes

As an athlete, adequate nutrition and hydration before, during, and after exercise are critical to getting optimal fuel for performance. 

Carbohydrates, protein, and fat all play different roles in fueling performance, so it’s important to ensure you’re getting enough of each leading up to your race or other strenuous activity. Plus, if your exercise or workouts last longer than an hour, you’ll need to consider how to fuel yourself during it so you have enough energy to keep going.

In this blog post, we’ll be discussing fueling for performance, specifically, eating strategies for athletes during race season. You’ll learn about the role of different macronutrients in athletic performance and how you can leverage strategic nutrition and hydration to perform your best on race day.

fueling for athletic performance

You need a combination of macronutrients to fuel for a marathon

Before going into what athletes should eat, it’s important to learn what macronutrients are.

Macronutrients, or “macros,” are nutrients that your body needs in large amounts for energy and optimal function. The three macronutrients are carbohydrates, protein, and fat. Each plays an important role in fueling athletic performance, so it’s crucial to make sure your nutrition plan includes all of them.


Carbohydrates are central to ensuring athletes have enough energy to complete their workout or get through a race. Most carbohydrates are broken down into sugar in the form of glucose, which provides energy to the cells.

Another form of carbohydrate is fiber, which the body can’t digest. However, some types of fiber are fermented by the gut bacteria.

The main functions of carbohydrates include:

  • Providing instant energy. Carbohydrates are the preferred fuel source for your brain, red blood cells, and central nervous system.

  • Storing energy. Glucose is converted to, and stored as, glycogen in your liver and muscles. This is especially important for endurance athletes because it provides fuel for the body once the glucose from your pre-workout meal is used.

  • Keep you feeling full. Fiber can help keep you full between meals.

  • Promote regular bowel movements. Fiber eases and regulates bowel movements. 

Eating enough carbohydrates is especially important for high-intensity performance. Although protein and fat can provide the energy needed to perform physical activity, carbohydrates are the most efficiently used by the body. They are the only macronutrients that can be broken down quickly enough to supply energy during high-intensity exercise.

Adequate carbohydrate intake is especially important for high-intensity and endurance performance. Proteins and fats can provide the energy needed to exercise, but carbohydrates are the most efficiently used macronutrient for energy.

Carbohydrate recommendations vary depending on an athlete's training intensity.

For individuals participating in a general fitness regimen, the International Society of Sports Nutrition (ISSN) suggests consuming between 3.0 and 5.0 grams of carbohydrates per kilogram of body weight daily.

Athletes engaging in moderate levels of intense training (e.g., two to three hours per day, five to six times weekly) should aim for approximately 5.0 to 8.0 grams of carbohydrates per kilogram of body weight daily.

Those undergoing high-volume intense training (e.g., multiple daily workouts, five to six times weekly) should target a carbohydrate intake of 8.0 to 10.0 grams per kilogram of body weight daily.

Examples of carbohydrate-rich foods include whole grains, starchy vegetables (such as corn and potatoes), fruits, pulses (like beans and lentils), as well as milk and yogurt.

Unsure of how many carbohydrates you need every day? Work with us here at Catalyst so we can provide individualized recommendations!

carbohydrates for athletic performance


Protein holds significance for athletes due to its role in muscle repair, which aids in the recovery process. Upon breakdown, protein transforms into amino acids.

The primary function of these amino acids is building and repairing tissues. They contribute to the formation of new proteins within the body, including immune system cells and enzymes, while also facilitating muscle repair and growth.

As recommended by the ISSN, athletes are advised to consume a daily protein intake ranging from 1.4 to 2.0 grams per kilogram of body weight to support muscle building and maintenance. Furthermore, emerging evidence suggests that higher protein consumption, up to 3.0 grams per kilogram of body weight, may enhance body composition among strength athletes.

The ISSN also offers guidance on protein distribution across meals. For optimal muscle growth, it’s advised to ingest between 20 and 40 grams of protein per meal, with meals evenly spaced throughout the day, ideally every three to four hours.

Protein-rich food options encompass poultry, fish, various meats (such as pork or beef), eggs, dairy products, as well as beans and lentils.


Fat plays a vital role in supporting athletes as it serves as a source of energy and aids in cell function.

Fats play several key roles in the body, including:

  1. Energy storage: Fat stores within the body act as a reserve fuel source, particularly when glucose and glycogen levels are depleted.

  2. Cellular insulation: Fat stores provide insulation and protection for organs within the body.

  3. Facilitating vitamin absorption: Fats play a crucial role in absorbing fat-soluble vitamins such as A, D, E, and K.

  4. Constituting cell membranes: Fats contribute to the structure of cell membranes, offering protection and regulating the passage of molecules.

Recommendations for fat intake among athletes align closely with those for non-athletes, with the ISSN suggesting that athletes derive approximately 30% of their daily calorie intake from fats. However, for athletes aiming to reduce body fat, this proportion may decrease to around 20%.

While there is growing interest in high-fat diets, such as the ketogenic diet, among athletes, studies investigating their impact on athletic performance and body composition have yielded mixed results. Thus, further research is necessary before endorsing the adoption of high-fat diets for optimizing athletic performance.

healthy foods for athletic performance

Pre-Workout Fueling

Fueling up before a workout or race not only enhances your performance but also reduces the risk of injury and promotes faster recovery.

Since carbohydrates take about four hours to digest and replenish muscle and liver glycogen stores, it’s optimal to consume a pre-exercise meal three to four hours beforehand. Including all three macronutrients—carbohydrates, protein, and fat—in this meal allows enough time for digestion.

Easy pre-workout meal ideas

- A chicken sandwich on whole wheat bread paired with a side salad.

- An egg burrito wrapped in a whole wheat tortilla with avocado, accompanied by a banana.

- Grilled fish served with brown rice and roasted vegetables.

Research indicates that consuming a light snack containing carbohydrates and protein (e.g., 50 grams of carbohydrates and 5 to 10 grams of protein) approximately 30 to 60 minutes before exercise can boost performance. Opt for easily digestible foods as pre-workout snacks.

Some examples of pre-workout snacks include:

- Cereal with milk.

- A banana paired with yogurt.

- A fruit smoothie.

Additionally, in the two to three days leading up to your competition, decrease training intensity by 30 to 50% and increase carbohydrate intake by 200 to 300 grams per day. This strategy helps replenish carbohydrate stores and enhances endurance before the athletic event.

During-Workout Fueling

Incorporating carbohydrates into your workout regimen serves as an external fuel source for both your muscles and central nervous system, a practice especially crucial during prolonged exercise when glycogen stores become depleted.

For events surpassing one hour, carbohydrate intake during exercise becomes imperative. Research indicates an optimal consumption range of 30 to 60 grams per hour, distributed at 15- to 20-minute intervals within the initial 2.5 hours of activity.

For durations exceeding 2.5 hours, elevating carbohydrate intake to up to 90 grams per hour may be necessary. Studies demonstrate that a blend of glucose and fructose enhances carbohydrate absorption rates. Therefore, aiming for 90 grams per hour is best achieved through a combination of these sugars.

During a race, nutrient supplementation aims to replenish lost fluids and sustain elevated blood glucose levels to fuel performance. Examples of intra-workout nutrition include sports drinks, energy gels, and maltodextrin powder mixed with water (adding honey can boost fructose content!).

It's advisable to integrate carbohydrate consumption into your training routine to allow your body to adapt. Starting with a conservative intake, such as 30 grams per hour, and gradually increasing enables you to gauge tolerance levels. The objective is to reach a carbohydrate intake of 60 to 90 grams per hour (depending on event duration) while avoiding digestive issues.

Post-Workout Fueling

The primary objective during recovery periods between training sessions or competitions is to replenish glycogen stores in the liver and muscles. Additionally, athletes may aim to promote muscle repair and growth.

Studies indicate that consuming carbohydrates that are easily digested, absorbed, and transported in the bloodstream is the most efficient method to restore glycogen stores post-exercise. This becomes especially crucial when training on consecutive days or twice within the same day.

However, carbohydrates alone are not sufficient for optimal recovery. It's equally important to intake adequate protein after exercise to facilitate muscle repair and growth. Research has shown that combining carbohydrates with protein in post-exercise meals improves overall performance compared to consuming carbohydrates alone.

Timing of your post-exercise meal is important, so consuming a blend of carbohydrates and protein within 30 minutes after completing a training session or race is recommended. It's also beneficial to have a meal rich in carbohydrates within 2 hours post-exercise.

Here are some examples of nutritious post-workout meals:

1. Grilled chicken breast with rice and roasted vegetables.

2. Salmon served with sweet potato and a side salad.

3. Cottage cheese paired with fruit.

4. Pita bread accompanied by hummus.

5. Tuna with crackers.

athletic performances such as running require a healthy diet

Hydration for Optimal Performance

Ensuring adequate hydration during exercise is crucial for optimizing performance. One effective strategy is to begin by hydrating sufficiently before starting physical activity, aiming to maintain normal body weight through fluid intake. According to the National Academy of Medicine, women should aim for 9 cups of fluid daily, while men should target 13 cups; those engaging in high activity levels may require more to maintain hydration.

Enhancing pre-exercise hydration involves consuming 500 mL of water or sports drink the evening before an event, followed by another 500 mL upon waking, and an additional 400-600 mL approximately 20-30 minutes before commencing exercise.

During exercise, it's recommended to consume 0.5 to 2 liters of fluid per hour to counteract fluid loss and prevent dehydration. This can be achieved by drinking 12 to 16 ounces of cold water or a sports drink every 5-15 minutes throughout the exercise session.

A critical point to remember is that relying on thirst as a cue to drink during exercise is unreliable. By the time thirst is perceived, substantial fluid loss through sweat has likely already occurred.

To gauge fluid loss during exercise, weigh yourself before and after the session. Aim to consume three cups of water for every pound of weight lost to aid in rehydration.

Additionally, increasing salt intake post-exercise, whether through sports drinks or salt added to foods, helps to optimize the rehydration process.

hydrating is a vital part of an athlete's diet

Final Thoughts on Proper Fueling for Performance

If you’ve been wondering, “What should athletes eat?” we hope you found this post useful.

When preparing for a race, maximizing your training efforts is crucial to achieving peak performance on race day. Ensuring adequate intake of carbohydrates, protein, fats, and fluids before, during, and after the race is essential to optimize your fueling strategy for optimal performance.

Need help planning your race nutrition? See a registered dietitian nutritionist at Catalyst Nutrition and Training! Through our nutrition counseling program, we can provide you with individualized nutrition guidance that takes your performance needs into account.

Schedule an appointment with us today to see how nutrition can help you reach your full athletic potential.


  • Slavin J, Carlson J. 2014. Carbohydrates. Advances in Nutrition, 5(6):760-1. doi: 10.3945/an.114.006163. 

  • Kanter M. 2018. High-Quality Carbohydrates and Physical Performance: Expert Panel Report. Nutrition Today, 53(1):35-39. doi: 10.1097/NT.0000000000000238. 

  • Kerksick, C.M., Wilborn, C.D., Roberts, M.D. et al. 2018. ISSN exercise & sports nutrition review update: research & recommendations. Journal of the International Society for Sports Nutrition, 15, 38.

  • Watford M, Wu G. 2018. Protein. Advances in Nutrition, 9(5):651-653. doi: 10.1093/advances/nmy027. 

  • Jäger, R., Kerksick, C.M., Campbell, B.I. et al. 2017. International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society for Sports Nutrition, 14(20).

  • Ahmed S, Shah P, Ahmed O. Biochemistry, Lipids. [Updated 2022 May 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:

  • Kloby Nielsen LL, Tandrup Lambert MN, Jeppesen PB. 2020. The Effect of Ingesting Carbohydrate and Proteins on Athletic Performance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients, 12(5):1483. doi: 10.3390/nu12051483.

  • Harvard T.H. Chan School of Public Health. (n.d.). Water. Retrieved May 12, 2023, from,exposed%20to%20very%20warm%20climates.

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