Do runners need more fat? The essential guide to fueling your runs

October 16, 2025 •

7 min read

According to the American College of Sports Medicine, athletes should aim to get 20-35% of their daily calories from fat. The question, 'Do runners need more fat?', is not about excess, but about integrating the right type and amount of healthy fats to optimize health, recovery, and long-distance performance.

Quick Summary

Runners require a specific balance of healthy fats for sustained energy, hormone regulation, and vitamin absorption. The optimal intake is 20-35% of daily calories, prioritizing unsaturated fats and timing them strategically around exercise.

Key Points

Adequate Fat Intake Is Vital: Runners need healthy fats, making up 20-35% of their total daily calories, for sustained energy, hormone regulation, and organ protection.
Focus on Healthy Unsaturated Fats: Prioritize sources like avocados, nuts, seeds, and oily fish for monounsaturated and polyunsaturated fats, which benefit heart health and recovery.
Time Fat Intake Strategically: Avoid high-fat meals right before a run to prevent digestive issues. Instead, incorporate healthy fats into meals and snacks away from immediate training time.
Embrace Metabolic Flexibility: The optimal approach is to train your body to use both fat and carbohydrates efficiently, rather than restricting one over the other, to maximize performance across different intensities.
Don't Undereat Fat: Restricting fat too much can negatively impact energy levels, overall health, and increase the risk of injuries and illness.
Know Your Macronutrient Balance: Consult with a sports dietitian or calculate needs based on training volume to ensure the correct balance of carbohydrates, protein, and fat for your personal goals.

Why fat is crucial for runners

For endurance athletes, dietary fat is more than just a source of calories; it's a critical component for overall health and peak performance. While carbohydrates are the body's primary fuel for high-intensity efforts, fat serves as a dense, long-lasting energy source during lower-intensity, prolonged exercise. A well-trained runner becomes more efficient at using fat for fuel, a process known as 'fat adaptation,' which spares valuable glycogen stores for when they are most needed.

Beyond providing energy, fat plays a crucial role in several physiological processes:

Nutrient Absorption: Fats are essential for the absorption of fat-soluble vitamins (A, D, E, and K), which are vital for immune function, bone health, and recovery.
Hormone Production: Fat intake is necessary for the production and balance of hormones, including those involved in muscle growth and repair. For female athletes, in particular, inadequate fat intake can disrupt hormone function and lead to issues like menstrual dysfunction.
Reducing Inflammation: Healthy fats, especially omega-3 fatty acids, possess anti-inflammatory properties that can aid in post-exercise recovery by reducing soreness and inflammation.
Protecting Organs: A layer of adipose tissue (body fat) helps protect vital organs from trauma.
Brain Health: Healthy fats, particularly omega-3s, are crucial for cognitive function and overall brain health.

Healthy vs. unhealthy fats for runners

All fats are not created equal. Runners should focus on incorporating healthy, unsaturated fats into their diet while limiting unhealthy saturated and trans fats. Here’s a breakdown:

Prioritize unsaturated fats

Monounsaturated Fats: Found in olive oil, avocados, and nuts, these fats can improve cholesterol levels and reduce heart disease risk.
Polyunsaturated Fats: These include essential omega-3 and omega-6 fatty acids, which the body cannot produce on its own. Sources like fatty fish (salmon, mackerel), flaxseeds, walnuts, and sunflower oil are excellent for heart health and reducing inflammation.

Limit or avoid other fats

Saturated Fats: Primarily found in animal products like red meat, butter, and full-fat dairy, these should be limited to less than 10% of total daily calories.
Trans Fats: These are industrially produced fats, often found in processed foods like cookies, crackers, and fried foods. They are detrimental to heart health and should be avoided entirely.

How much fat do runners need?

While specific macronutrient ratios can vary based on individual needs and training load, general recommendations for endurance runners fall within the Acceptable Macronutrient Distribution Range (AMDR) for fat. For most runners, getting 20-35% of total daily calories from fat is a sensible approach.

For Moderate-Intensity Training: A split of approximately 50-60% carbohydrates, 20% protein, and 20-30% fat is generally recommended.
Individualization: A runner’s training volume will influence their needs. A serious athlete logging high mileage may need to adjust their macro intake, consulting with a sports dietitian for personalized advice.

Strategic fat timing around your runs

Fat is digested more slowly than carbohydrates, so timing your fat intake is crucial to avoid gastrointestinal issues during a run.

Before a Run: It is generally recommended to keep fat intake low in the meal or snack consumed in the hour or two before a training run, especially if it's high-intensity. A light, carbohydrate-rich snack is best for easily accessible fuel.
Throughout the Day: Integrate healthy fats into meals and snacks away from training time. This provides sustained energy and supports overall health.
Post-Run Recovery: A meal with a mix of carbohydrates, protein, and healthy fats (like avocado with eggs on toast) is excellent for refueling and aiding muscle recovery. The anti-inflammatory properties of healthy fats also help repair muscles.

The high-fat, low-carb debate

Some endurance athletes experiment with high-fat, low-carbohydrate (LCHF) diets, like the ketogenic diet, to encourage fat adaptation. The idea is to train the body to burn fat more efficiently, preserving glycogen.

However, research suggests this approach has drawbacks for most runners, particularly those performing at high intensities. While LCHF can increase fat oxidation, it can impair exercise economy and reduce performance during higher-intensity efforts where carbs are the preferred fuel. The ultimate goal for most athletes is metabolic flexibility—the ability to switch between fat and carbohydrate fuel sources as needed based on exercise intensity.

Conclusion

So, do runners need more fat? The answer is a definitive yes, but the emphasis should be on the right type of fat, not simply more of it. A balanced approach that integrates sufficient healthy fats is essential for overall health, prolonged energy, optimal recovery, and maximizing endurance potential. Instead of chasing restrictive, high-fat, low-carb trends, runners should aim for a macronutrient balance that supports their training needs, prioritizing unsaturated fats and timing their intake strategically. This strategy allows the body to maintain the metabolic flexibility needed for both long, steady efforts and high-intensity bursts. By prioritizing good fats, runners can fuel their performance and support their bodies for the long run.

Outbound link

For more information on balancing your diet for athletic performance, consult the resources at Sports Dietitians Australia.

Comparison Table: Fat Sources for Runners


Category	Recommended Fats (Unsaturated)	Limited/Avoid (Saturated & Trans)
Energy	Provides long-term, sustained energy.	Can contribute to energy, but unhealthy for heart.
Sources	Avocado, olives, nuts, seeds, fatty fish, flaxseeds, olive oil.	Red meat, butter, palm oil, processed foods (fried foods, cakes).
Health Impact	Improves heart health, reduces inflammation, aids brain function.	Raises bad (LDL) cholesterol, increases risk of heart disease.
Digestion	Moderate intake aids overall health; time away from workouts.	Slows digestion; can cause GI distress before a run.
Nutrient Function	Helps absorb fat-soluble vitamins (A, D, E, K).	Offers no added nutritional benefit compared to unsaturated fats.
Recovery	Anti-inflammatory properties aid muscle repair.	Can increase inflammation, hindering recovery.

Key takeaways

Fat is Essential: Runners need a specific, balanced amount of fat for energy, hormone balance, and nutrient absorption.
Choose Healthy Fats: Prioritize monounsaturated and polyunsaturated fats from sources like avocados, nuts, seeds, and fish, while limiting saturated and avoiding trans fats.
Maintain Balance: Aim for 20-35% of daily calories from fat, balancing with carbohydrates for high-intensity fuel and protein for muscle repair.
Strategize Timing: Eat healthy fats throughout the day, but limit them in the meal immediately before a run to avoid stomach upset.
Embrace Metabolic Flexibility: The ideal strategy is training your body to be efficient at using both fat and carbohydrates, not relying solely on a high-fat approach.
Don't Restrict Too Much: Extreme low-fat diets can negatively impact energy, performance, and increase the risk of injury.

FAQs

Question: How much fat should a runner consume daily? Answer: For most runners, a fat intake of 20-35% of total daily calories is recommended. This amount can vary depending on training intensity and individual needs.

Question: What are the best sources of healthy fat for runners? Answer: Excellent sources of healthy fats include avocados, nuts (walnuts, almonds), seeds (chia, flax), olive oil, and fatty fish like salmon and mackerel.

Question: Is a ketogenic diet recommended for runners? Answer: While ketogenic diets can increase fat oxidation, they may negatively impact high-intensity performance. For most runners, a balanced diet that includes carbohydrates for peak performance is preferred over the highly restrictive keto diet.

Question: Why should I avoid fat before a run? Answer: Fat digests slowly. Consuming a high-fat meal immediately before a run can lead to gastrointestinal distress and discomfort during exercise. It's best to eat a carbohydrate-focused meal or snack for quick energy.

Question: What happens if runners don't eat enough fat? Answer: Insufficient fat intake can lead to inadequate energy, poor performance, a greater risk of illness or injury, and impaired absorption of vital fat-soluble vitamins.

Question: Does eating fat make you a better endurance runner? Answer: Not necessarily. While fat is a key fuel for endurance, a runner's performance is optimized by achieving metabolic flexibility—the ability to efficiently use both fat and carbohydrates based on the intensity and duration of the run.

Question: How does fat adaptation happen for runners? Answer: Fat adaptation is a natural metabolic process that occurs from consistent aerobic training. This trains the body to burn fat more efficiently, especially at lower exercise intensities, thereby preserving glycogen stores for high-intensity efforts.

Citations

How Much Fat Should Runners Eat Per Day? runnersworld.com.
Integrating Dietary Fat: A Guide for Endurance Runners. extension.usu.edu.
Running and nutrition: Your questions answered. runnersworld.com.
Integrating Dietary Fat: A Guide for Endurance Runners. extension.usu.edu.
How Much Fat Should Runners Eat Per Day? runnersworld.com.
Fat and the Endurance Athlete. trainingpeaks.com.
Dietary Fat and Sports Performance. sciencedirect.com.
How Much Fat do Athletes Need in a Diet? nutritionx.co.uk.
A Free Athlete's guide to dietary fat. freeletics.com.
Food for Distance Running. sportsdietitians.com.au.
The ultimate nutrition guide for runners. centr.com.
A Free Athlete's guide to dietary fat. freeletics.com.
Nutrition for Long-Distance Runners. bodyfixclinic.co.uk.
An athlete's guide to understanding dietary fat. nswis.com.au.
What should a runner's macros be? elo.health.
Running and nutrition: Your questions answered. runnersworld.com.
Integrating Dietary Fat: A Guide for Endurance Runners. extension.usu.edu.
Low-Carb, High-Fat Diets and Endurance Performance. uphillathlete.com.
Very Low Carb (Keto) Diet and the Endurance Athlete, Part 2. grsm.ca.
The Science and Practice Behind Fat Adaptation. uphillathlete.com.
Fat adapt & metabolic: Should you train your body to burn more fat? dietitianapproved.com.

Frequently Asked Questions

For most runners, a fat intake of 20-35% of total daily calories is recommended. This amount can vary depending on training intensity and individual needs.

Excellent sources of healthy fats include avocados, nuts (walnuts, almonds), seeds (chia, flax), olive oil, and fatty fish like salmon and mackerel.

While ketogenic diets can increase fat oxidation, they may negatively impact high-intensity performance. For most runners, a balanced diet that includes carbohydrates for peak performance is preferred over the highly restrictive keto diet.

Fat digests slowly. Consuming a high-fat meal immediately before a run can lead to gastrointestinal distress and discomfort during exercise. It's best to eat a carbohydrate-focused meal or snack for quick energy.

Insufficient fat intake can lead to inadequate energy, poor performance, a greater risk of illness or injury, and impaired absorption of vital fat-soluble vitamins.

Not necessarily. While fat is a key fuel for endurance, a runner's performance is optimized by achieving metabolic flexibility—the ability to efficiently use both fat and carbohydrates based on the intensity and duration of the run.

Fat adaptation is a natural metabolic process that occurs from consistent aerobic training. This trains the body to burn fat more efficiently, especially at lower exercise intensities, thereby preserving glycogen stores for high-intensity efforts.