The Top 10 Biggest Mistakes Endurance Athletes Make
By: Steve Born
Steve's nearly three decades of involvement in the sports nutrition industry, as well as more than 20 years of independent research in nutritional fuelling and supplementation, have given him unmatched familiarity with the myriad product choices available to athletes. — Who is Steve?
1. EXCESS HYDRATION
Optimum nutritional support for endurance athletics means consuming the right amount of the right nutrients at the right time. You can neither overload nor undersupply your body without compromising athletic performance and potentially creating problems.
The principle of avoiding both too much and too little especially applies to hydration. If you don't drink enough, dehydration can impair performance. Drink excessive amounts, however, and you can also impair performance and, in extreme circumstances, increase the risk of potentially dangerous exercise-associated hyponatremia.
One of the most respected researchers on hydration, Dr. Tim Noakes, has extensively studied hydration practices in endurance athletes. One of the important lessons from this work is that more fluid is not automatically better.
Endurance athletes too often adopt the "if a little is good, a lot is better" approach. This can lead to significant problems when you're trying to meet your hydration requirements.
All it takes is one poor performance or DNF involving cramping or dehydration and you may start thinking, "Maybe I didn't drink enough." Next thing you know, you're drinking so much that your thirst is quenched, but your stomach is sloshing and you're still uncomfortable.
Remember: both undersupply and oversupply can cause problems.
How much should you drink?
Fluid requirements vary considerably according to athlete size, exercise intensity, temperature, humidity, acclimatisation and individual sweat rate.
Hammer has traditionally found that many athletes perform well with approximately 500–750 ml per hour, with some needing less and others more depending on conditions.
The key is not to blindly chase a fixed number.
Drink according to your individual requirements, conditions and experience — and avoid forcing down fluid simply because a schedule says you should.
RECOMMENDATION
For many endurance athletes, approximately 500–750 ml per hour provides a sensible starting range.
In cooler conditions or at lower intensities you may require less. Hotter conditions and heavier sweating may increase requirements.
If fluid intake rises significantly, electrolyte requirements may also change.
The goal is balance — not maximum fluid consumption.
For more detail, read our [Hydration for Running, Cycling & Endurance Exercise]
2. SIMPLE SUGAR CONSUMPTION
Hammer Nutrition has long favoured maltodextrin and complex carbohydrate-based fuelling rather than building its endurance fuels around large amounts of added simple sugars such as glucose, fructose and sucrose.
There is an important reason for this.
Carbohydrate concentration influences the number of dissolved particles in a drink or gel and therefore its osmolality. Maltodextrin consists of chains of glucose molecules and can provide a substantial amount of carbohydrate with fewer individual particles than an equivalent amount of free glucose.
This allows maltodextrin-based fuels to deliver useful carbohydrate calories without creating the same concentration of individual sugar molecules in solution.
For endurance athletes, this can be especially useful when fuel needs to be consumed repeatedly for many hours.
Modern research also shows that athletes can successfully use mixtures of different carbohydrate sources, including glucose and fructose, particularly at higher carbohydrate intakes.
Hammer's philosophy, however, remains deliberately different.
Our aim isn't to encourage every athlete to consume the maximum amount of carbohydrate they can tolerate. Instead, we favour an appropriate amount of fuel, using maltodextrin as the primary carbohydrate source, combined with Hammer's Less is Best approach.
This helps athletes avoid unnecessarily aggressive calorie intake while still supplying practical carbohydrate energy for training and racing.
RECOMMENDATION
Choose endurance fuels that provide carbohydrate in a form you tolerate well and test them thoroughly in training.
Hammer Gel and HEED use maltodextrin as their primary carbohydrate source and are excellent choices for shorter endurance sessions and races.
For longer workouts and events, Perpetuem is specifically designed to provide sustained multi-hour fuel.
For a deeper explanation of Hammer's carbohydrate philosophy, read [Maltodextrin – The Superior Carbohydrate for Endurance Athletes]
3. IMPROPER AMOUNTS OF CALORIES
Too many endurance athletes fuel their bodies under the premise:
If I burn 500–800 calories an hour, I must consume that much or I'll bonk."That simply isn't how endurance fuelling works.
During prolonged exercise your body is drawing energy from several sources, including stored glycogen, body fat and the fuel you're consuming.
Trying to replace calories at the same rate you burn them is neither necessary nor practical for most endurance athletes.
Endurance exercise is, by its nature, a deficit-spending activity. The objective is to postpone fatigue and maintain performance, not replace every calorie, every ml of fluid and every electrolyte lost while exercising.
Athletes who repeatedly attempt calorie-for-calorie replacement may unnecessarily overload the digestive system.
Keep this in mind during ultra-endurance events, especially if circumstances prevent you from sticking to your planned hourly intake.
For example, let's say you've been consuming an average of 150 calories per hour, but extreme heat, a long climb or another race circumstance means you temporarily consume less.
Do not automatically try to make up all the missed calories at once.
Doing so may create more digestive problems than it solves.
Return gradually to your normal fuelling strategy when conditions allow.
RECOMMENDATION
Hammer's long-standing philosophy is to determine your Minimum Calories Per Hour (MCPH).
For many athletes, approximately 120–180 calories per hour provides a useful starting range, although requirements will vary according to body size, intensity, duration, conditions and individual metabolism.
Larger athletes or particularly demanding circumstances may require more.
Your focus should NOT be: "How much can I consume?"
Instead ask:"What is the minimum amount of fuel I need to keep my body performing effectively hour after hour?"
Fine-tune your intake through training under a variety of conditions.
For our full explanation, read [How Many Calories Per Hour Do You Need During Endurance Exercise?]
4. INCONSISTENT ELECTROLYTE SUPPLEMENTATION
Consuming sufficient calories and fluids during prolonged workouts and races is important.Electrolyte intake may also be an important part of your strategy, particularly during long-duration exercise, hot conditions and periods of significant sweating.
Electrolytes including sodium, chloride, potassium, calcium and magnesium perform important physiological roles throughout the body.
However, this doesn't mean athletes should indiscriminately consume large quantities of one mineral.
Sodium is often the primary focus in endurance sport, but Hammer has always favoured a full-spectrum electrolyte approach rather than treating electrolyte replacement as simply consuming increasing quantities of salt.Requirements also vary dramatically between athletes.
Sweat rate, sweat sodium concentration, temperature, acclimatisation, duration, diet and individual physiology all influence how much electrolyte support an athlete may require.
Electrolyte intake can also remain relevant when conditions aren't particularly hot. You may require less than during extreme heat, but duration and individual sweat characteristics still matter.
RECOMMENDATION
Use a balanced electrolyte product and adjust your intake according to your individual needs and conditions.
[Endurolytes] provides six electrolytes in an easy-to-adjust capsule format.
Athletes with substantially higher sodium requirements, heavy sweat rates or particularly hot conditions may prefer Endurolytes Extreme or Endurolytes Extreme Powder.
The goal is **precision and individualisation**, not simply consuming as much sodium as possible.
5. IGNORING PROTEIN DURING VERY LONG EXERCISE
During prolonged endurance exercise, carbohydrate remains the body's most important external fuel source.
As duration increases, however, amino acid and protein metabolism also form part of the body's overall energy and muscle-protein turnover processes.
Hammer's long-standing position is that a small amount of protein can be useful during prolonged multi-hour exercise, particularly during ultra-endurance events where athletes are fuelling continuously for many hours.
This is one reason Perpetuem combines carbohydrate with soy protein and a small amount of fat rather than relying exclusively on carbohydrate.
The objective isn't to turn an endurance fuel into a high-protein meal.
It is to provide a small amount of protein alongside carbohydrate as part of a fuel designed specifically for prolonged endurance exercise.
Soy protein also provides a complete amino acid profile and works well in Hammer's long-duration fuelling formulation.
THOUGHTS ON PROTEIN INTAKE
Soy's remarkable donation to endurance performance is deserving of our review.
— William Misner, Ph.D., Director of Research & Product Development, Emeritus
For workouts and races lasting several hours, consider [Perpetuem] your primary long-distance fuel.
Perpetuem combines carbohydrate, soy protein and fat in a formula designed for sustained endurance exercise.
Protein during exercise should remain modest and purposeful. Carbohydrate remains the primary fuelling component.
6. TOO MUCH SOLID FOOD DURING EXERCISE
In the 1985 Race Across America (RAAM), Jonathan Boyer rode to victory using liquid nutrition as his primary fuel source.
Since then, liquid and semi-liquid nutrition has become an extremely practical option for endurance and ultra-endurance athletes.
Drink mixes and gels allow athletes to control calorie intake precisely and are usually easier to consume while running or riding than large quantities of solid food.
Solid food can absolutely have a place during endurance exercise, particularly during very long events where texture, taste and variety become important.
But large quantities of solid food can require more digestive work and may feel increasingly difficult to tolerate at higher exercise intensities.Hammer therefore favours liquid or gel-based nutrition as the foundation, with solid food used strategically where appropriate.
Occasional solid food intake can provide a welcome diversion during ultra-endurance efforts. If you choose to use solid food, follow two principles:
PAY ATTENTION!
1. Choose familiar, easily tolerated foods and avoid suddenly introducing large amounts of very fatty, extremely high-fibre or unfamiliar food during competition.
2. Use solid food as part of your overall strategy rather than automatically relying on it as your primary source of fuel.
RECOMMENDATION
Use Hammer Gel, HEED and/or Perpetuem as your primary endurance fuels according to the duration and nature of your event.
These make it easier to control calorie intake and build a repeatable fuelling strategy.
If you want solid food, [Hammer Bar] provides a practical whole-food option for longer sessions where something more substantial is desirable.
7. USING SOMETHING NEW IN A RACE WITHOUT HAVING TESTED IT IN TRAINING
The title is pretty self-explanatory.
It's one of THE cardinal rules for endurance athletes, yet you'd be amazed how many break it.Unless you're absolutely desperate and willing to accept the consequences, do not try anything completely new in competition — equipment, fuel, hydration strategy, supplements or tactics.
Test and refine these things in training.Your gut can adapt to what you regularly practise, and race nutrition is a skill just like pacing, bike handling or running economy.
RECOMMENDATION
Hammer Nutrition fuels are designed to work together, giving you the flexibility to tailor a fuelling programme for different race durations and conditions.
Try different combinations during training and keep a record of what works.Your training log shouldn't only record distance, pace and power.
Record:
- calories consumed
- fluid intake
- electrolyte intake
- products used
- weather conditions
- stomach comfort
- energy levels
That information becomes invaluable when building your race-day plan.
8. STICKING WITH YOUR GAME PLAN EVEN WHEN IT'S NOT WORKING
Endurance athletes tend to be strong-willed and uncompromising.Having a race plan is an excellent idea.Having a nutritional plan that you've refined during training is equally important.But don't slavishly follow that plan if race-day conditions clearly tell you it needs adjusting.
What worked during training may not always work identically during competition.Race intensity, heat, humidity, altitude, nerves and duration can all influence your ability to consume and digest fuel.
If the weather becomes very hot, for example, you may find that your stomach handles calories differently.Continuing to force down the exact same amount of fuel simply because the spreadsheet says so can create unnecessary problems.
Listen to your body.Make sensible adjustments.If you temporarily need to reduce calorie intake, do so and resume your normal strategy gradually when you feel able.The same thinking applies to training after a disappointing race.A poor race doesn't automatically mean you need more training.Sometimes the correct response is recovery, analysis and adjustment, not simply increasing workload.
RECOMMENDATION
Have a game plan that includes a fuelling protocol you have refined during training.But remain flexible.Evaluate conditions and your body's response throughout the race.
Have a game plan — but write it in pencil, not in ink.
9. INADEQUATE POST-WORKOUT NUTRITION
Performance improvement depends on a cycle of training followed by recovery.Exercise provides the stimulus.Recovery is where the body adapts.That makes post-workout nutrition an important part of any serious endurance training programme.
After long or demanding training, your priorities should include:
- replacing fluids appropriately
- restoring carbohydrate
- consuming sufficient protein
- returning to a balanced daily diet
- getting adequate rest and sleep
Carbohydrate helps replenish muscle glycogen used during exercise, while protein provides amino acids needed for muscle repair and maintenance.
The urgency of recovery nutrition depends partly on how hard and how long you've trained and when you need to perform again.
Athletes training again later the same day or early the next morning have a stronger reason to begin recovery nutrition promptly than athletes who have a full day or more before their next demanding session.The important point is not to neglect recovery.
RECOMMENDATION
After long or demanding sessions, consume carbohydrate and high-quality protein as part of your recovery strategy.
[Recoverite] provides a 3:1 carbohydrate-to-protein ratio, with 30 g carbohydrate, 10 g whey protein isolate, glutamine and electrolytes per serving.For a complete approach, read our [Recovery Nutrition for Endurance Athletes]
10. IMPROPER PRE-WORKOUT/RACE FUELLING
Far too often, athletes put themselves at a disadvantage before a workout or race by eating too much, eating foods they haven't tested, or mistiming their pre-race nutrition.
Three common mistakes are:
1. Overeating the night before in the hope of "carbo loading"Your pre-race meal isn't an excuse for an eating competition.For longer endurance events, appropriate carbohydrate intake in the days leading into competition can help support glycogen availability.
But that doesn't mean stuffing yourself with an enormous meal the night before.
Eat familiar foods, eat enough, and avoid turning dinner into a digestive challenge.
2.Over-consuming calories in the pre-workout or pre-race meal.The objective is to begin the race well fuelled without starting with an overloaded stomach.A moderate, familiar carbohydrate-rich meal several hours before exercise works well for many athletes.Your ideal amount will depend on body size, race duration and what you've successfully practised in training.
3. Eating at the wrong time
Pre-race timing matters.Hammer has traditionally favoured finishing the main pre-race meal approximately three hours before the start, giving the digestive system time to settle.
Modern sports-nutrition recommendations allow a wider pre-exercise window depending on meal size and individual tolerance.
The important rule remains the same:
Know what works for you before race day.
RECOMMENDATION
Don't go overboard with food the night before a workout or race.
Follow these principles:
1. Eat familiar, high-quality food.
2. Eat until comfortably satisfied rather than stuffed.
3. Avoid experimenting with unfamiliar foods.
4. Finish your main pre-race meal with enough time to digest comfortably.
5. If you use a small last-minute carbohydrate top-up, make sure you've already tested it in training.
Read our full guide: [What to Eat Before a Race]
HONOURABLE MENTION
OVERCOMPENSATING IN THE DAYS LEADING UP TO A RACE
Far too many athletes overdo calorie, fluid and salt consumption in the days before competition because they believe they can build up extra reserves.More isn't automatically better.
FLUIDS
Don't suddenly drink huge quantities of water in the hope of "pre-hydrating".Drink normally and consistently in the days leading into your event and arrive at the start appropriately hydrated.Your fluid needs depend on body size, environment, training load, diet and individual sweat losses.
CALORIES
Don't turn the days before your event into an uncontrolled eating spree.For events where carbohydrate loading is appropriate, the goal is to increase carbohydrate availability intelligently, not simply increase total calories without limit.Continue eating familiar foods and avoid the temptation to eat substantially more simply because a race is approaching.
SODIUM
Likewise, don't indiscriminately load sodium before the event unless you have a specific reason and a strategy you have tested.Individual sodium requirements vary substantially.
Athletes who sweat heavily or have high sweat-sodium losses may require more than athletes with low losses, but this should be approached individually rather than by automatically adding large amounts of salt.
TRAINING
And finally, don't try to cram extra fitness into the final few days.You cannot meaningfully transform your aerobic fitness immediately before race day, but you can certainly arrive tired.
Reduce the workload appropriately, recover, sleep well and arrive at the start ready to use the fitness you've already built.
THE HAMMER PRINCIPLE
Most of these mistakes share the same underlying problem:
Too much, too late, too complicated or never tested.
Hammer Nutrition has spent decades encouraging endurance athletes to take a more measured approach.Fuel appropriately.Hydrate appropriately.Replace electrolytes according to your needs.Practise everything in training.Recover properly.And don't assume that more automatically means better.
That's the philosophy behind Less is Best
Find what your body actually needs, refine it through training and then execute it consistently on race day.
Hammer on.
FURTHER READING
BUILD YOUR ENDURANCE FUELLING STRATEGY
Avoiding common fuelling mistakes is only part of the equation. The next step is building a simple nutrition strategy that suits your event duration, intensity, conditions and individual requirements.
As a general starting point:
- Shorter endurance sessions and races: HEED and/or Hammer Gel provide practical carbohydrate energy, with fluid and electrolytes adjusted according to conditions.
- Longer endurance events: Hammer Gel can be combined with an appropriate hydration and Endurolytes strategy.
- Multi-hour and ultra-endurance events: Perpetuem is specifically formulated as a sustained long-distance fuel containing carbohydrate, soy protein and fat.
- After long or demanding training: Recoverite provides carbohydrate and whey protein isolate to support post-exercise recovery.
Whatever products or strategy you choose, practise it in training before relying on it in competition.
New to endurance nutrition? Our Beginner's Guide to Endurance Fuelling explains what to use before, during and after exercise and provides a straightforward starting point for building your own fuelling plan.
You can also explore our dedicated Running Nutrition, Cycling Nutrition and Triathlon Nutrition guides for sport-specific advice.
FREQUENTLY ASKED QUESTIONS
How much should an endurance athlete drink per hour?
Fluid requirements vary according to athlete size, exercise intensity, temperature, humidity, acclimatisation and individual sweat rate.
Hammer has traditionally found that approximately 500–750 ml per hour provides a useful starting range for many endurance athletes, with some athletes requiring less and others more.
The important point is not to force down fluid simply to hit a predetermined number. Your hydration strategy should be refined through training and adjusted according to conditions and your individual requirements.
How many calories per hour should I consume during endurance exercise?
Hammer's Minimum Calories Per Hour (MCPH) philosophy focuses on determining the minimum amount of fuel needed to support consistent performance rather than attempting to replace every calorie burned.
For many athletes, approximately 120–180 calories per hour provides a useful starting range, although requirements vary according to body size, exercise intensity, duration, conditions and individual metabolism.
This is Hammer's fuelling philosophy rather than a universal requirement. Test and refine your intake in training.
Are simple sugars or maltodextrin better for endurance exercise?
Both simple sugars and maltodextrin can provide carbohydrate energy during exercise.
Hammer Nutrition deliberately uses maltodextrin as the primary carbohydrate source in products such as Hammer Gel and HEED.
Maltodextrin consists of chains of glucose molecules and can deliver substantial carbohydrate while contributing fewer individual dissolved particles than an equivalent amount of free glucose.
Modern sports-nutrition research also demonstrates that combinations of carbohydrate sources such as glucose and fructose can be effective, particularly when athletes are consuming high carbohydrate intakes.
Hammer takes a different approach: rather than encouraging every athlete to consume the maximum carbohydrate intake they can tolerate, we combine maltodextrin-based fuelling with our Less is Best philosophy.
What should I eat before an endurance race?
Choose familiar foods that you have already successfully used before training.
A moderate carbohydrate-rich meal several hours before exercise works well for many athletes. Hammer has traditionally favoured completing the main pre-race meal approximately three hours before the start, although individual requirements and meal size will influence the ideal timing.
Avoid turning the night before a race into an eating competition. The aim is to arrive appropriately fuelled without beginning the event with an overloaded digestive system.
What nutrition should I use for endurance events lasting longer than three hours?
For prolonged multi-hour exercise, your nutrition strategy needs to consider fuel, hydration and electrolytes together.
Hammer Gel can provide portable carbohydrate energy, while Perpetuem is specifically formulated for longer endurance exercise using carbohydrate, soy protein and a small amount of fat.
Electrolyte intake can then be adjusted independently using Endurolytes or Endurolytes Extreme according to individual requirements and conditions.
Whatever combination you choose, test the complete strategy during long training sessions before race day.
FURTHER READING & SCIENTIFIC REFERENCES
The following research provides additional scientific context for the hydration, carbohydrate, gastrointestinal training, pre-event nutrition and recovery topics discussed in this article.
Hew-Butler T, et al. Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clinical Journal of Sport Medicine. 2015;25(4):303–320. DOI: 10.1097/JSM.0000000000000221.
Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Journal of the Academy of Nutrition and Dietetics. 2016;116(3):501–528. DOI: 10.1016/j.jand.2015.12.006.
Jeukendrup AE. Training the Gut for Athletes. Sports Medicine. 2017;47(Suppl 1):101–110. DOI: 10.1007/s40279-017-0690-6.
Jeukendrup AE. Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Current Opinion in Clinical Nutrition and Metabolic Care. 2010;13(4):452–457. DOI: 10.1097/MCO.0b013e328339de9f.
Burke LM. Nutrition strategies for the marathon: fuel for training and racing. Sports Medicine. 2007;37(4–5):344–347. DOI: 10.2165/00007256-200737040-00018.
Alghannam AF, Gonzalez JT, Betts JA. Restoration of Muscle Glycogen and Functional Capacity: Role of Post-Exercise Carbohydrate and Protein Co-Ingestion. Nutrients. 2018;10(2):253. DOI: 10.3390/nu10020253.
Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition. 2017;14:20. DOI: 10.1186/s12970-017-0177-8.
These references provide broader scientific context for endurance nutrition. Hammer's Minimum Calories Per Hour and Less is Best approaches represent Hammer Nutrition's specific fuelling philosophy and should not be interpreted as universal sports-nutrition guidelines