Quick Tip: The goal is not to try to consume every calorie of output. It's generally a bad idea to try to consume every calorie you burn while training, even at a competitive racing level. Why? The limiting factor is digestion. Your body is under physical stress while training, and does not want or need to deal with huge amounts of food and drink (many athletes burn upwards of 1,000 calories per hour at high intensity).
In many ways, less is more, and you'll avoid many stomach and low energy issues by consuming enough, but not too much, in small amounts every hour of training.
More: The Diet Detective: Know Your Calories
Key #3: Electrolytes
These are the tiny, often-forgotten, deal-breaker nutrients of training nutrition. Don't get enough, and you'll risk dehydration, over-hydration and/or the big bonk. It's a balancing act, but not too difficult to accomplish.
Electrolytes—and especially sodium—are needed during training to improve carbohydrate absorption, water/fluid absorption, and to maintain the delicate balance of plasma fluids and particles in your blood. Potassium, chloride, calcium and magnesium, can also play a factor, but don't seem to be as acutely necessary as sodium.
More: Electrolytes and When to Replace Them
| Weight Loss | Performance | Competitive |
| Electrolyte Needs: If training for >2 hours, ensure you're getting 100-300 mg potassium. If training >3 hours, take 80 mg calcium, and 40 mg magnesium per hour. | Electrolyte Needs: Follow the weight-loss guidelines for potassium, calcium and magnesium. | Electrolyte Needs: |
| Electrolyte Choices: Add a small amount of table salt (1/12 tsp = 200 mg sodium) to your drink. Take calcium and magnesium supplements before and after training in amounts that equal or exceed what's needed per hour. | Electrolyte Choices: Then, follow the calcium, magnesium and salt guidelines listed for the weight-loss group. Consider the electrolytes in your carb options when determining if you need to add more. | Electrolyte Choices: |
| Comments: | Comments: | Comments: |
Quick Tip: It's not too much water, but too little sodium or other electrolytes that causes over-hydration. Generally, over-hydration occurs when the ratio of fluid in the plasma is no longer balanced with the amount of sodium in the plasma. The electrolytes are diluted. By only drinking water when training, especially when sweating a lot due to intensity, heat and humidity, you're at high risk for diluted electrolytes if you're only drinking water.
More: 7 Drinks That Boost Performance
What's more, your body may choose to dehydrate further and cause an increase in urine output in an effort to reduce bodily fluid and re-establish fluid to electrolyte balance. Either way, it's not a good situation.
Remember: fluids, carbs and electrolytes. The types and amounts depend on your goals, and training intensity and duration. Of course, you can go beyond these three keys and look at amino acids, whole proteins, functional nutrients and more to optimize your plan. Sometimes these really help, and other times they cause more problems than they're worth.
Above all else, the three keys of training nutrition are the best place to start. They're the foundation, and they'll make a big difference in your performance.
More: The Role of Nutrition in Athletic Performance
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About the Author
Kelli Jennings, RD and sports nutritionist, is the owner of Apex Nutrition, LLC. Kelli helps athletes reach their weight goals and build strength, endurance and stamina. She teaches clients to eat for reduced inflammation, the best recovery and ongoing fueling needs as they push themselves to new levels. Like Kelli on Facebook, and follow her on Twitter.
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