The answer comes down to one fact, the body processes sugar differently during exercise and at rest. Once you grasp that distinction, the fear of sugar goes away. It’s a tool and like any other it can do harm or good depending on how you use it.
Your body handles sugar in two different ways
When you’re riding, your body flips a switch. Hormones, blood flow, and even your brain’s energy demands shift to prioritize immediate fuel delivery to your muscles. Here’s what happens:
Insulin, the hormone that signals your body to store sugar, drops. Instead, glucagon ramps up, directing sugar straight to your working muscles.
Epinephrine kicks in: This “fight-or-flight” hormone unlocks muscle glycogen and boosts cardiac output, getting you ready for action.
Blood vessels dilate which means that more oxygen and fuel reach your muscles faster.
In this state, sugar isn’t stored as fat, it’s burned for energy. Your body is in performance mode, not storage mode.
At rest, your body goes back to increased insulin activity to replenish glycogen stores. Glucagon decreases, and epinephrine levels drop allowing for the “rest and digest” mode to start. Your body shifts to storage mode, topping up energy reserves for your next ride.
The key difference: For athletes, replenishment and storage are healthy because we regularly deplete our glycogen stores through training. For sedentary people, excess sugar with no outlet to burn it off can lead to metabolic problems, weight gain, and serious health risks down the line.
How much carbohydrate should you consume?
All of the above doesn’t mean you should eat as much sugar as possible when you hop on a bike. Not all rides demand the same fuelling strategy. Here’s how to tailor your intake based on intensity, duration, and what your gut can handle.
Under 60 minutes: Carbohydrates are generally unnecessary for short rides like this, you glycogen stores are enough to cover this amount of time.
30–60g/hour: For 90+ minutes of cycling at low to mid intensity.
60–90g/hour: For moderate to strenuous rides lasting 90+ minutes. Getting to 90g per hour takes some practice a time for the gut to adapt.
120g+/hour: These amounts are reserved for pros at race intensities. They need specific performance carb mixes and a lot of training before they’re able to handle this much. The main benefit of these amounts is to recover well to next day in a packed racing schedule.
Your teeth are still in harm’s way
Drinking bottles of carb mix on long rides and enjoying a post-ride sweet dessert may sound like a recipe for diabetes. Now we know that during and shortly after exercise, sugar is used up and doesn’t increase the risk of negative health outcomes. Well, except one. All of that sugar still needs to go through your mouth and teeth when consuming it. And that means an increased risk of cavities. Studies have shown that professional cyclists struggle with tooth decay more often. Brushing teeth becomes that much more important.
What should your relationship with sugar look like?
You can enjoy all the benefits and pleasures of sugar and reduce the negative effects to a minimum if you respect how your body deals with sugar. Let’s summarize the key points to take away.
Sugar during exercise ≠ sugar at rest. Your body processes it differently.
Reserve most of your sugar intake for cycling or right after it.
Match your sugar intake to the duration and intensity of your riding.
Train your gut, don’t go from zero to 120 g of carbs per hour in one week. Gradually increase carb tolerance to avoid GI issues.
Compensate for the increased sugar intake by increasing your oral hygiene.
Be more conservative with sugar intake on easy days and rest days.
