What’s in your Bottle: Part 4: If you can’t hack it…

No matter what the numbers recommend, if you can’t tolerate your fuel, you can’t burn it

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  • You should be training like you intend to race; that counts for nutrition, too
  • Are you a “sugar burner” or a “fat burner?”
  • The length of the event, the intensity of the event, your fitness, and your weight are the factors that determine your race nutrition
  • You can’t process what you can’t tolerate
  • Without carbs, you bonk. Without water, well, it’s more dire than that.
  • During-event nutrition isn’t the only thing to think about: pre-event and post-event are critical considerations, too

The amounts you consume are as important as what you’re consuming

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The concept of tolerance


comes into play here, as well as a concept called “caloric compensation” (which is far too advanced and lengthy a discussion for even this extended blog series. The skinny is — you don’t want to pound in way more calories than you’re actually burning in exercise, and especially after exercise.) These are some of the big reasons why so many of the guidelines for nutrition come wrapped in wide ranges.

[callout icon=”hb-moon-bike”]In addition to fitness, you need to consider tolerance. In other words, how much carb can you take in before your body is simply unable to process it.[/callout]

In our last installment, we looked at the 50–60 grams per hour range for high intensity efforts. If you’re really fit, you can process about 1 gram per hour. Since our new racer in our little case study is, well, new, we looked at the lower end. In practice, we may learn that he can only deal with 45 grams or so. In addition to fitness, you need to consider tolerance. In other words, how much carb can you take in before your body is simply unable to process it. If your body can’t deal with it, and it’s sloshing around in your gut undigested, you’re going to have gastric upset. And that’s going to seriously hamper your performance.

If you have a power meter (which, admittedly, few beginner racers will…) it will tell you in kilojoules, which are roughly equivalent to calories, how much effort you just put out in a workout or race. You’re not seeking to replenish the calories you just burned; just because your power meter said you burned 750 kJs, that doesn’t mean you want a 750 calorie meal. Your body doesn’t reset to a zero-baseline every 24 hours. Calorie consumption just isn’t that linear. But a power meter will help you regulate the amount of total pre, during, and post effort eating you’re doing. 

Fuel up early. This is especially true for sugar burners. Prior to a hard workout or race, and during the first 30 minutes of a race, you want to get a significant portion of your total carbohydrate needs (90 grams in our previous installment’s example) into your system. The reason for this is that, while really going at it, your body simply doesn’t want to take in nutrients. It would prefer to rely on stored energy, or glycogen, which inhabits your muscles and your liver. Any carbs you put in while you’re in full tilt, either in intervals or during that breakaway, will have to be converted to glucose to do you any good. That takes time and energy away from all the other work your body is trying to do.

If you’re a fat burner, your primary strategy is to fuel up day to day and pre-effort with dense nutrients, then use on-bike foods for keeping your already highly-rich energy stores topped up. The simple-sugar gels and energy drinks that are commercially available for cycling aren’t optimal for a fat burner’s diet. However, in the midst of high energy efforts, you need those easily convertible sources to maintain your performance. Burning fat is easiest during low to moderate efforts. (Otherwise known as “endurance pace.”)

Any simple sugars you use will be more readily burned as you ingest them, and you’ll need to rely upon them less. Fat burners simply have more efficient energy conversion systems, because their bodies can tap into stored fats for the endurance portions of the effort. But that doesn’t mean you can go without carbohydrate replenishment during hard workouts or races that are exceeding 75 minutes or so if you are a fat burner. Do your calculations based on our 50-60 grams per hour, but instead of simple sugar choices as primary go-tos, consider supplementing with more complex carbs. Homemade rice cakes filled with peanut or almond butter and jam, for example are nutrient dense and of lower glycemic content. Bananas come with a natural wrapper, and pack as much carb as an energy gel. Organic honey, apple butter, fruit and a squeeze of lemon juice can be thickly blended and put into runner’s belt bottles for delicious substitutes for prepackaged gels.

[icon_box icon=”hb-moon-bike” icon_position=”left” align=”left”]Question: If you’ve arrived at a during-effort mixture of carbs (or other elements, such as proteins and fats) that work for you, what is it, and how did you go about determining it? [/icon_box]

Sam Lowe

I've been a road cyclist with a penchant for speed ever since my first-ever paycheck holiday. I blew the whole wad on a turquoise Schwinn Tempo with then-new Shimano 105 indexed shifting way back in 1985. I've been a voracious consumer of racing-oriented information ever since. Training, nutrition, bike fit, racing techniques, and all manner of "kit." Between nearly 30 years of riding, racing, and reading about racing, I'm ready to help you get ready to race.

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