Fruit Sugar Sounds Healthier. But Is It a Good Fuel for Your Ride?

Fruit is healthier than sugar-based snacks, but when your muscles need to fuel harder endurance exercise, fructose can’t replace glucose.

In a new study, recreational cyclists rode at their maximal lactate steady state while consuming either glucose, fructose, or a placebo. At the same carbohydrate intake of 60 grams per hour, glucose increased time to exhaustion by about 25% compared with placebo, while fructose had no effect on performance.

This doesn't mean you should stop eating fruit on a ride. Fruit contains varying mixtures of fructose, glucose, and sucrose, along with water, fiber, and other nutrients. And for an easy-to-moderate ride of just a couple of hours, your body's carbohydrate stores will provide much of the fuel you need. Rather, make your snacking decisions based on the intensity and duration of the ride you have planned.

Fructose does have a role in fueling longer and higher-intensity endurance riding. Although fructose alone performed poorly compared with glucose alone in the current study, we know that fructose added to glucose can increase total carbohydrate absorption. So when carbohydrate requirements are approaching roughly 60 to 90+ grams per hour, combining glucose with fructose means the body can absorb and burn more total carbohydrate than relying on glucose alone.

Fueling during exercise is different from choosing foods for everyday health. At the dinner table, you should be thinking about fruits, vegetables, whole grains, fiber, and limiting added sugars. But during a long or demanding ride, the carbohydrate you consume has a different job: get absorbed quickly, maintain blood glucose, and provide fuel to working muscle.