Fueling Guidelines That Are Easy to Follow and Incorporate
Proper fueling of the body prior to, during, and after exercise requires personal experimentation to find the ideal fit for you, the individual athlete. There is no “one size fits all” approach; we are all “experiments of one" when it comes to fueling during exercise. You need to determine, through trial and error in your training, what works best for you. However, there are some basic guidelines that will enable you to eliminate much of the guesswork, so you can more rapidly learn how to properly fuel your body during workouts and races.
Some of these recommendations may seem pretty foreign to you, especially in regards to fluid, calorie, and electrolyte replenishment during exercise, where some “experts” tell you that you need to eat and drink at or near depletion rates. Before you subscribe to and follow those suggestions, consider the words of Bill Misner, Ph.D.:
The human body has so many survival safeguards by which it regulates living one more minute, that when we try too hard to fulfill all its needs we interfere, doing more harm than good. If I replace all the fuels I lose at the rate of 700-900 calories per hour, I bloat, vomit, present diarrhea, and finish the event walking or at an aid station. If I replace all the fluids lost all at once, I end up in the emergency tent with an IV for dilutional hyponatremia. If I replace all the sodium my body loses at the rate of 2 g/hour, I end up with swollen hands, eyes, ankles, feet, and noticeably labored exercise, or hypernatremia-induced bonking.
Pretty bold words (and warnings), indeed. The truth is that you don’t need to suffer with these undesirable maladies; they’re not a mandatory part of being an athlete. If you follow our suggestions, we believe you will not only avoid performance-ruining and potentially health-threatening consequences, you will also have much more enjoyable experiences and achieve better performances in your workouts and races. These suggestions have their roots in science and have been proven time and time again (and again and again) over the course of several years. You have nothing to lose, and a whole lot to gain, by testing them in your training. I’m betting that the more of the following recommendations you adopt and practice in your training and racing, the fewer problems you’ll run into fueling-wise and the better your performance will be.
There’s probably more misinformation on the subject of hydration than any other aspect of fueling, which is really bad because overhydration also presents the most serious physiological consequences of any fueling issue. Acute overhydration can cause hyponatremic (low sodium) induced coma and death.
Most athletes, under most conditions, will satisfy hydration needs with a fluid intake in the 20-28-ounce/hr range. Cool weather exercise might require only a little over half of that. Big athlete, very hot and humid conditions—maybe up to 30 ounces. Sure, you can sweat more than that, but you cannot physiologically replace it ounce-for-ounce. Regular fluid intake over 30 ounces hourly really increases the potential for serious performance and health problems, so keep that in mind before you indiscriminately gulp down excessive amounts of fluid. If you override your internal mechanisms, you’ll find out the hard way how your body deals with excess water intake during intense exercise. Unless you enjoy nausea, bloating, and DNFs, forget advice like “drink to replace” or “drink even when you’re not thirsty”—it’s just plain wrong.
2. Restrict caloric intake to 300 cal/hr during exercise.
If you want to watch your race go down the drain fast, follow the “calories out, calories in” protocol that some “experts” recommend. Fact: your body can’t process caloric intake anywhere near your expenditure rate. Athletes who attempt to replace all the fuels they lose—which can be upwards of 700-900 calories per hour—will most likely end up with bloating, nausea, vomiting, and/or diarrhea. Sound like a good strategy to you? We didn’t think so.
If you want to achieve your best performance, replenish calories in “body cooperative” amounts, allowing your fat stores to make up the difference, which they will easily do. For most athletes, 240-300 cal/hr will do the job. For lighter athletes, 180-200 cal/hr may be just the ticket, while larger athletes can consider hourly intakes of slightly over 300 cal/hr.
Far too many athletes think they need to match calories out with equal amounts of calories in. They’re usually the ones on the side of the road or off the back, waiting for their stomach to stop rebelling. If you follow a more sensible caloric intake, you’ll be blowing by them, not joining them.
3. Avoid simple sugars in your fuels; use complex carbohydrates only.
You’ve heard the phrase “garbage in, garbage out,” right? Guess what—simple sugars (glucose, sucrose, fructose, and dextrose) are garbage. They’re inefficient fuels for exercise, and they’re health hazards when consumed regularly in typical dietary quantities. They have no place in your body.
This leads to the question, “Why do companies include these types of sugars in their products?” Most likely because simple sugars are cheap, they sweeten the product, and they allow the label to read, “Packed with XX carbs per serving.” But just look at the side panel to find out what you’re really getting.
Simple sugars give you energy peaks and crashes, and they also have a severe limitation on absorption. They need to be mixed in weak concentrations for efficient digestion, which means you can only intake about 100 cal/hr. You can consume more, but you can’t absorb more. You’ll only get sick trying. Complex carbohydrates, however, absorb at about three times the rate as simple sugars. That covers the 300 cal/hr we just mentioned. Plus you get smooth, steady, reliable energy—no peaks and valleys. Yes, complex carbohydrates do contain, as part of their naturally occurring structure, a small percentage of 1- or 2-chain sugars. There’s a big difference, however, regarding how your body responds to these sugars when they are “part of the whole” rather than when they’re isolated and added to a product as a separate ingredient… big difference.
Look, we’re not going into a long physiology lesson now; we just want to save your body, your health, and your performance. If you take the “garbage in, garbage out” concept with any seriousness you’ll avoid the glucose/sucrose/fructose/dextrose products and stick with complex carbohydrate fuels.
Part 2 covers the use of protein and electrolytes during training.