At a recent cycling camp, I was talking with Dave, a 42-year-old father of two who was training for an annual cycling weekend with friends. He was making progress, but was frustrated with his performance during long rides—once he passed three hours, he started having stomach trouble. As he rattled off a list of what he consumed each hour on the bike—half an energy bar, one gel, a bottle of sports drink and a bottle of water—I realized he was eating and drinking too much. He needed to revisit his bike nutrition plan.
The American College of Sports Medicine recommends 30-60 grams of carbohydrate per hour of exercise, but few athletes understand the reason for this amount. The average person can process, or oxidize, only about 1 gram of carbohydrate per minute, no matter how much is consumed. The bottleneck isn’t your muscles: it’s your intestines, which can transport glucose from the food you eat into your bloodstream only so fast. Dumping more carbohydrates into your gut doesn’t necessarily increase the absorption rate, and it can increase your chances of an upset stomach.
It’s easier than you think to overload on carbs. Take Dave as an example. His half an energy bar (23 grams of carbs), one gel (27 grams of carbs) and bottle of sports drink (about 50 grams of carbs) meant he was taking in about 100 grams of carbohydrate every hour. Early in his rides, he was doing great because he was getting all the fluid, energy and sodium his body could handle, but after a few hours the excess carbohydrate sloshing around in his system was making him nauseous, bloated and ill. (Get a better understanding of your body’s needs by tracking and analyzing nutrition, mood, sleep, workouts, and more in the Bicycling Ride Journal!)
One of the easiest ways to optimize your carbohydrate intake during rides is to drink a low-carb, electrolyte hydrating drink while you’re eating light, digestible snacks, like fig bars and bananas. Simply separating these two categories—hydration and solid food—typically brings people back into the range of 30 to 60 grams of carbohydrate per hour, while also ensuring they’re getting adequate sodium and fluids.
Also, new research suggests that by consuming energy foods that contain a mix of sugars (such as glucose and fructose, or glucose and maltodextrin) instead of just one type, you can bump oxidation to as much as 1.7 grams per minute.
Over the course of three days at camp, Dave made subtle changes in his on-bike eating habits. He set an alarm to beep every 15 minutes as a reminder to drink, instead of guzzling an entire bottle at once. He added granola bars and fig bars to his stash of energy bars and gels for variety. As we rolled past the four-hour mark, Dave was taking long turns at the front and chatting happily in the paceline as if the ride had just begun.