Nutrition For Endurance Athletes: Carbs, Protein, and Fats

Endurance athletes have specific nutrition requirements to support their training, performance, and recovery. As they engage in prolonged and intense physical activities, their bodies demand a steady supply of energy and nutrients. Keep reading to learn exactly what endurance athletes need to stay nourished and hydrated.

Key takeaways:

Endurance athletes participate in activities that require prolonged periods of physical exertion, such as long-distance running, cycling, swimming, and triathlons. These activities demand substantial energy expenditure and place unique demands on the body, making proper nutrition crucial for optimal performance and overall health.

Caloric intake

Endurance athletes typically require more calories than sedentary or moderately active people due to their higher energy expenditure.

The German Journal of Sports Nutrition found “TEE (total energy expenditure) of endurance athletes is approximately 1.8 to 2.3-fold as high as the individual’s resting energy expenditure, but may be up to 4-fold in professional endurance athletes during short periods.” Even at rest, endurance athletes need nearly 2 times the caloric intake of a sedentary or moderately active person and 4 times the calories while they're training. That is a lot of energy to consume to keep up with the physical demands of endurance athletes!

The exact caloric needs vary based on factors such as training intensity, duration, body weight, and metabolism. It's essential to work with a sports nutritionist or dietitian to determine the appropriate calorie intake for each athlete’s needs.

Macronutrients: carbs, protein, and fats

We know endurance athletes need more calories, but how much of each food group should they be eating exactly?

Overall, the International Sports Sciences Association suggests endurance athletes eat with the following ratios, being sure to get enough protein (based on body weight), then calculating the remaining calories with ratios that work best for each individual athlete:

  • 10–35% of calories from protein
  • 45–65% of calories from carbs
  • 20–35% of calories from fat

Below is a more detailed breakdown of each macronutrient and what research suggests endurance athletes should be consuming to keep up with their unique energy demands.


Nutrients Journal states “high carbohydrate diets have long been tested and continued to be recommended in endurance athletes” because carbohydrates are the primary source of energy for endurance athletes.

“Carbohydrate-rich foods (cereals, vegetables, legumes and products thereof) should be the major source to account for elevated energy demands. During low-intensity training periods, a carbohydrate intake of 3–5 g/kg/d seems to be appropriate to meet the demands of endurance athletes, whereas requirements may rise up to 8–12 g/kg/d during high-intensity training periods” as the German Journal of Sports Nutrition found.

Focus on complex carbohydrates such as whole grains, fruits, vegetables, and legumes as the added fiber slows digestive emptying and ensures sustained longer-term energy. During prolonged exercise, consuming easily digestible carbohydrates like energy gels, sports drinks, or snacks can help maintain energy levels.


Protein is crucial for muscle repair and recovery. Endurance athletes should consume adequate protein to support their training and prevent muscle breakdown. Good sources of protein include lean meats, poultry, fish, eggs, dairy products, legumes, nuts, and seeds.

“The AND, DC, and ACSM all recommend protein ingestion for athletes in the range of 1.2–2.0 g/kg/day […] this strategy may promote positive nitrogen balance and optimally benefit endurance athletes. Attention to adequate intake is emphasized to improve recovery, ameliorate muscle damage, and maintain muscle mass” as Nutrients Journal found in their review of endurance athletes and their nutrient needs.


Healthy fats are an essential part of an endurance athlete's diet as they provide sustained energy. Include sources of unsaturated fats like avocados, nuts, seeds, and olive oil. Omega-3 fatty acids, found in fatty fish like salmon, can also help reduce inflammation and support cardiovascular health.

A study conducted in the International Journal of Environmental Research and Public Health found that endurance athletes' diets consisted of 30–35% fat intake in order to maintain caloric needs. Fatty acids are essential to nerve and brain function, as well as hormone production. Endurance athletes should eat plenty of fatty fish, grass-fed meats, organic dairy, nuts/seeds, and avocados to reach their fat intake goals.


Proper hydration is vital for endurance athletes to maintain performance and avoid dehydration. The International Sports Sciences Association found that “as little as a 1–2% reduction in body weight due to water loss can result in decreased athletic performance” so it is essential for endurance athletes to stay hydrated!

It’s important to drink the right amount of water, enough to prevent dehydration but not so much that electrolyte imbalance occurs. Endurance athletes must pay attention to electrolytes such as sodium, potassium, magnesium, and calcium, as they are lost through sweat during prolonged exercise. Electrolyte-rich foods like bananas, oranges, and sports drinks can help replenish these essential minerals. Adding minerals and sodium to water or drinking isotonic sports drinks can help maintain electrolyte balance and improve endurance athlete performance.

Micronutrients: vitamins and minerals

A balanced diet should provide most of the vitamins and minerals an endurance athlete needs. However, paying attention to vitamins like B-complex, vitamin C, and minerals like iron and calcium is essential, as they play crucial roles in energy metabolism, immune function, and bone health.

The Journal of Sports Medicine found vitamin C to be essential in boosting immunity, protecting the cells against free radical damage, supporting wound healing, and “helping athletes recover during the competitive season." Citrus fruit and berries are great sources of natural vitamin C.

Iron is essential for endurance athletes as it is involved in oxygen transport within the blood. Prolonged training can lead to iron loss, especially in female athletes due to menstruation. Foods rich in iron include lean meats, dark leafy greens, beans, and fortified cereals.

Both calcium and vitamin D are critical for bone health, which is crucial for athletes engaged in repetitive and high-impact activities. Dairy products, fortified plant-based milk, leafy greens, and sunlight exposure are good sources of these nutrients.

Timing: pre- and post-exercise nutrition

The timing of meals and snacks is crucial for endurance athletes. Consuming carbohydrates and fluids during long training sessions or competitions can help maintain performance and delay fatigue. Consuming a meal or snack that includes carbohydrates and a small amount of protein before training or competition can help maintain energy levels and delay fatigue.

After a strenuous workout, refueling with carbohydrates and protein is essential for muscle recovery and glycogen replenishment. Aim to eat a balanced meal or snack within 30–60 minutes of finishing exercise.

Remember, personalized nutrition advice from a registered dietitian or sports nutritionist is highly beneficial for endurance athletes, as they can create a specific plan based on individual goals and needs. Additionally, experimentation during training can help identify what works best for each athlete. You may want to try a few different approaches before finding the right combination for you!

Leave a reply

Your email will not be published. All fields are required.