Nutrition for endurance athletes has evolved from being a marginal topic to a central factor in achieving peak performance. However, despite increasing interest, misinformation persists, leading to critical mistakes that can undermine performance, recovery, and long-term health. From misconceptions about carb-loading to misleading fasting practices, many athletes fall prey to myths that can harm their progress.
In this article, we debunk seven common endurance nutrition myths and explain the science behind them. These insights come directly from a certified sports dietitian with extensive experience supporting endurance athletes at all levels.
Endurance Athlete Nutrition Misconceptions
1. Myth: Eating More Food Will Improve Performance
Some athletes believe that carb-loading or consuming large meals before a race will boost energy. However, overeating—especially right before an event—can backfire, often leading to bloating, cramps, and stomach discomfort, particularly when unfamiliar foods or excessive fiber and carbs are consumed.
Why it happens:
During exercise, blood flow shifts from the digestive system to working muscles (de Oliveira et al., 2014), reducing digestive efficiency and increasing the risk of gastrointestinal issues.
Additionally, more carbs don’t always mean more fuel. A 2020 review found that while carb consumption before exercise is essential, higher intake doesn’t necessarily increase carb metabolism during exercise (Rothschild et al., 2020). However, skipping carbs can lead to inadequate performance. The key is timing and moderation.
Takeaway:
Eat foods your body tolerates well. Focus on easily digestible carbs before a race and test fueling strategies during training, not on race day.
2. Myth: Fast-Digesting Carbs Are Always Better During Exercise
It’s commonly believed that “fast” carbs like glucose are superior for energy during long events. However, this is too simplistic.
Here’s why: Your body can only absorb 60 grams of a single sugar type per hour (Jeukendrup, 2014). However, combining different sugars—like glucose and fructose—allows the body to utilize up to 90 grams per hour or more.
Example:
One study found that a glucose-fructose mixture increased carbohydrate oxidation by 75% compared to glucose alone (Currell & Jeukendrup, 2008).
What this means for you:
- For shorter events (under 2 hours), a single sugar source is often sufficient.
- For longer events, use products with multiple transportable carbs (e.g., glucose + fructose or maltodextrin + fructose) for better energy and digestion.
3. Myth: It Doesn’t Matter How You Get Your Calories
Some athletes think that as long as they hit their calorie or macronutrient targets, it doesn’t matter whether their nutrition comes from solid food or liquids. However, this is not true, especially during endurance events.
Why it matters:
- Solid foods require more digestion, which can be problematic during high-intensity activities like running.
- Liquid nutrition (e.g., gels or drink mixes) is absorbed faster and causes fewer stomach issues, especially during long races.
Tips:
- Cyclists: Can tolerate solid options like energy bars or rice cakes.
- Runners/triathletes: Stick to fluids or gels paired with water for easier digestion.
4. Myth: Fats Don’t Help with Performance
Many endurance athletes avoid fats, believing they digest slowly and don’t support energy needs. This is only partially true.
Here’s the nuance: While fats digest more slowly and shouldn’t be consumed in large amounts before a race, your body relies heavily on fat metabolism during longer, lower-intensity efforts—especially if you’re well-trained.
Fun fact:
Elite endurance athletes often burn more fat and conserve glycogen during exercise. A diet too high in carbs and low in fats can lead to performance plateaus.
Suggestions:
- Include healthy fats (e.g., nuts, seeds, and oily fish) in your diet.
- Avoid high-fat foods just before training or racing.
5. Myth: If It Works for Them, It’ll Work for Me
Copying someone else’s nutrition plan—whether it’s your training partner’s or a pro athlete’s—can be risky.
Why?
Everyone has different energy needs, digestive speeds, sweat rates, and metabolic responses.
Example:
If an amateur cyclist tries to match a pro’s intake—say, 100g carbs/hour and 1 liter of water—they might feel bloated or sluggish. High carb intake without proper adaptation can overwhelm the gut.
Proven approach:
Start with general guidelines (e.g., 30–60g carbs/hour) and adjust based on your training data, body weight, and personal tolerance.
6. Myth: I Should Constantly Drink Water During Exercise
Overhydration can be just as dangerous as dehydration.
During long endurance events, your body loses both fluids and electrolytes (sodium, potassium, chloride). Replacing only water can lead to hyponatremia, a potentially life-threatening condition caused by low sodium levels in the blood.
What to do instead:
- Use electrolyte mixes or sports drinks, especially during long events or in hot weather.
- Measure your sweat rate to tailor fluid intake.
Extra tip:
Drinking cold liquids in hot environments can help lower core body temperature.
7. Myth: Training Fasted Helps Burn More Fat
“Training low” (with low carb availability) is a trendy strategy but comes with risks—especially for endurance athletes.
The problem:
Fasted training is catabolic. Without adequate carbs or protein, your body may break down muscle tissue for energy (Tarnopolsky, 2004).
The solution:
Fuel your training with carbs and some protein to protect muscles and support recovery. For long sessions, intra-workout protein (e.g., BCAAs or small protein-carb combos) can help reduce muscle breakdown.
Important note:
Fasted training can be effective if used selectively and in the right training phase—but it shouldn’t be your default approach.
Conclusion: Personalization Beats Popularity
Understanding endurance nutrition requires more than following trends. It’s about recognizing your body’s unique needs and adapting accordingly. The most effective strategy is personalized, evidence-based, and tested during training—not on race day.
If you’d like help optimizing your endurance nutrition, consider a personalized consultation with our sports dietitian. Whether online or in person, we can help you fuel smarter and perform better.
References
- Tarnopolsky, M. (2004). Protein requirements for endurance athletes. Nutrition, 20(7–8), 662–668.
- Currell, K., & Jeukendrup, A. E. (2008). Superior endurance performance with ingestion of multiple transportable carbohydrates. Medicine & Science in Sports & Exercise, 40(2), 275–281.
- Jeukendrup, A. (2014). A step towards personalized sports nutrition: Carbohydrate intake during exercise. Sports Medicine, 44(Suppl 1), S25–S33.
- de Oliveira, E. P., Burini, R. C., & Jeukendrup, A. (2014). Gastrointestinal complaints during exercise: Prevalence, etiology, and nutritional recommendations. Sports Medicine, 44(Suppl 1), S79–S85.
- Rothschild, J. A., Kilding, A. E., & Plews, D. J. (2020). What should I eat before exercise? Nutrients, 12(11), 3473.
