Remember that fat and protein have slow gastric emptying times and you don't want to start a race such as a criterium with a ham and cheese sandwich competing for that much needed blood flow to your muscles. Many riders may even regurgitate that undigested food during a race. Not ideal or enjoyable.
During your race or training, the same rules apply. Eating raw salted almonds, bread with almond butter, bars with bacon and cheese or other high fat foods, will result in slower gastric emptying. That means even if you eat them in combination with a sports drink or chews, the entire meal gets held up. Now your much needed carbohydrates will take longer to get to the working muscles. You're also creating competition for blood again, potentially causing indigestion and heavy legs.
For athletes convinced that they feel better on their morning 90-minute hammer sessions due to their high fat breakfast or raw coconut they just ate, remember this: It takes about 2 hours for long chain triglycerides to even get to your intestines, even if they're used as an energy source. The reality is for any ride under 2 hours, even if fat didn't slow your gastric emptying rate, it would still be quite useless.
Why Carbohydrates Are a Better Choice
Fat is the last nutrient to get processed. Most fat digestion occurs in the small intestine with minimal digestion occurring in part to enzymes in saliva and in the stomach. This is why we don't consume fats while racing: The digestion is slow.
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The bottom line is at almost all times you are using carbohydrates and fat as fuel while cycling. The higher the intensity the more you rely on carbohydrates as fuel, the lower the intensity, the larger percentage of fat you will use as fuel. Although fats are a great source of energy, their slow gastric emptying and inability to be used at very high intensities, makes them a poor fuel of choice while cycling.
The ideal fuel choice while cycling a typical distance bike race is still high-density carbohydrate foods, low in fat and fiber.
It's important to note that the rules of every day health do not apply to on bike nutrition. This can be difficult for some cyclists who are extremely health conscious off the bike.
A typical off the bike meal is ideal when it empties the stomach slowly, has some fat, fiber, protein and carbohydrates. During the day we want slow blood sugar release and we want to feel full for a long time, controlling our hunger and energy levels.
On the bike, we have a different scenario. It's important to differentiate the two for optimal performance and GI comfort. Separate "performance nutrition" and "daily nutrition" in your mind. Be willing to let go of the "healthy" foods in order to gain a performance advantage. Once you are off the bike, get right back to your healthy habits and you will be right on track. So don't throw your energy bars and gels away just yet.
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