Eat. Drink. Don't Bonk.
Most people come to cycling from other sports or activities. Maybe it's the gym, maybe it's running, maybe it's group fitness classes. And that's great. But here's the thing: those activities probably aren't true endurance efforts that require you to think about fueling and hydrating for a longer, sustained activity.
We can all get through an hour at the gym without eating. No one brings a sandwich to OrangeTheory. And it's very common for someone new to cycling to say something like: "I burned 700 calories in a spin class and didn't need to eat. I'll be fine."
I've heard this many times. And that kind of thinking gets riders in trouble.
A 45-minute spin class and a 3-hour training ride are fundamentally different animals. The fueling strategy that works for one will absolutely fail you on the other.
The Science (Keep It Simple)
Your body stores energy as glycogen in your muscles and liver. Think of it as your gas tank. The average person stores roughly 1,500 to 1,800 calories of glycogen, and a trained endurance athlete can store more. That sounds like a lot, but here's the problem: cycling at a moderate pace burns somewhere between 500 and 800 calories per hour. At higher intensities, even more.
Do the math. If you start with a full tank and you're burning through it at that rate, you have roughly 90 to 120 minutes before your glycogen reserves drop to a level where your body simply cannot sustain the effort. Your muscles run out of readily available fuel.
When that happens, you bonk.
Bonking is not just "being tired." It comes on suddenly and it is unmistakable. One minute you feel fine, and the next minute your legs feel like concrete, your brain gets foggy, you can't hold a conversation, and the idea of pedaling one more mile feels physically impossible. Your body is telling you the tank is empty. Some riders get dizzy or lightheaded. Some get emotional. It is deeply unpleasant, and it can be dangerous if you're on the road in traffic.
The critical thing to understand is that bonking is preventable. It is almost always caused by not eating or drinking enough during a ride. It is not a sign that you aren't fit enough. It's a sign that you didn't fuel properly.
01 Eating on the Bike
The goal is simple: replace some of the carbohydrates you're burning before your glycogen stores bottom out. You don't need to replace all of them. You just need to keep the tank from hitting empty.
Here are the general guidelines used by sports nutritionists and the cycling community:
Under 60 minutes: You're fine. Your glycogen stores can handle it. Just drink water.
60 to 90 minutes: A small snack or an energy drink is a good idea, especially if you're riding hard. This is the gray zone.
90 minutes to 3 hours: Aim for 30 to 60 grams of carbohydrates per hour. That's roughly one energy bar, one banana, or two gels per hour.
3+ hours: You need 60 to 90 grams of carbs per hour. This is the territory where fueling is no longer optional. It's the difference between finishing and not finishing.
The most important rule: start eating early. Don't wait until you feel hungry. By the time you're hungry, you're already behind, and it takes time for your body to process and absorb what you eat. Most coaches recommend eating something within the first 30 to 45 minutes of a longer ride and then continuing on a schedule every 20 to 30 minutes after that.
What Should You Eat?
There's a massive sports nutrition industry built around this question, but the honest answer is: whatever works for your stomach. Here's a rough hierarchy:
Energy gels are the most efficient option. They're compact, fast-absorbing, and easy to eat while riding. Brands like GU, Maurten, and SIS are popular. Some have caffeine. They taste like sweet paste. Most people either love them or tolerate them.
Energy bars and chews are a step up in terms of substance. They give you something to actually chew on, which some riders prefer. Clif Bars, Skratch chews, and Honey Stinger waffles are popular options.
Real food absolutely works. Bananas, PB&J sandwiches cut into quarters, fig bars, rice cakes, even salted potatoes. Professional cyclists eat real food on the bike all the time. If your stomach handles it well, there's nothing wrong with it.
Practice eating on training rides. Don't try anything new on ride day. Your stomach needs to get used to digesting while your body is working hard, and different products affect different people differently. Find what works for you and stick with it.
02 Drinking on the Bike
Dehydration sneaks up on you. By the time you feel thirsty, you've already lost performance. The general rule of thumb is one standard cycling water bottle (roughly 20 to 24 ounces) per hour. In hot weather, closer to two bottles per hour.
But here's where it gets more nuanced: water alone isn't always enough.
For rides under an hour, plain water is totally fine. But once you get past 60 to 90 minutes, you're losing electrolytes through sweat, specifically sodium, potassium, and magnesium. These are the minerals that keep your muscles firing and your brain functioning. Losing too many of them causes cramps, fatigue, and in extreme cases, a dangerous condition called hyponatremia (when your sodium levels drop too low).
This is why sports drinks and electrolyte mixes exist. They aren't just marketing. For longer rides, mixing an electrolyte powder into one of your water bottles makes a real difference.
Bottle 1: Plain water. Good for quick sips, splashing on your face, washing down food.
Bottle 2: Water mixed with an electrolyte/carb drink like Skratch Labs, Nuun, Liquid IV, or Gatorade Endurance. This is your fuel bottle.
On rides over 2 hours, drink the electrolyte bottle first. Those carbs take time to get into your bloodstream, so the earlier you start, the better.
Drinking too much plain water without electrolytes can actually be dangerous. It dilutes your sodium levels and can lead to hyponatremia, which causes confusion, nausea, and in serious cases, seizures. The goal is steady, moderate intake throughout the ride. Not chugging a whole bottle at once every 45 minutes.
Putting It All Together
Here's what a fueling plan looks like for a typical training ride of 2.5 to 3 hours, the kind of distance we'll be doing as we build toward the big ride:
The Spin Class Trap
Let's come back to where we started. The spin class mentality.
A 45-minute spin class might burn 400 to 700 calories. That's intense, but it's short enough that your glycogen stores can handle it without any mid-workout fueling. You sweat, you're tired, you grab a smoothie after. No problem.
A 3-hour training ride at moderate effort burns somewhere around 1,500 to 2,400 calories. That's a completely different equation. Your glycogen tank, even fully topped off, cannot cover that on its own. Without eating on the bike, you will hit a wall. It's not a question of toughness or fitness. It's basic physiology.
"I crushed it in spin class on nothing but a coffee. I'll be fine on today's 40-mile ride."
Result: bonk at mile 25, drop from the group, crawl home, question all life decisions.
Breakfast 2 hours before. Two full bottles (one water, one electrolyte). A gel at 45 minutes, a bar at 90 minutes, a gel at 2 hours.
Result: strong all day, finish with the group, actually enjoy the ride.
For Our T1D Riders
This is the Ride to Cure Diabetes. Many of the riders on our team are living with Type 1 Diabetes, and everything I just wrote about fueling and hydration applies to you too. You are a human who needs fuel to ride a bike. But you also have a layer of complexity that other riders don't, and it deserves its own conversation.
I am not qualified to give you medical advice. I want to be clear about that. But I have been coaching T1D riders for over 20 years, I live with T1D in my own family, and I've seen what works and what doesn't on the road. So here's what I'll say:
You cannot wing this. You cannot figure it out as you go. You need a strategy for managing your blood sugar on training rides, and you need to develop that strategy before you show up for your first long ride. Work with your endocrinologist or diabetes care team to build a plan specific to you.
Endurance cycling dramatically increases insulin sensitivity. Your metabolism is jacked during a ride and can stay that way for hours afterward. The insulin-to-carb ratio that works for you at the dinner table will not work for you on the bike. If you don't adjust, you are at serious risk of hypoglycemia, and that is dangerous on a bicycle in traffic at 18 miles per hour.
Here are some of the tools and strategies that T1D riders use. Again, your specific approach should be developed with your care team:
Exercise mode. Most modern insulin pumps and closed-loop systems (Omnipod 5, Tandem Control-IQ, Medtronic 780G, and others) have an exercise or activity mode. This raises your blood sugar target, typically to around 150 mg/dL, and reduces automatic insulin delivery so your system isn't fighting your muscles for glucose. The important thing: activate it early, at least 1 to 2 hours before the ride. The algorithm needs time to adjust.
Temp basal. If your pump supports temporary basal rate adjustments, reducing your basal rate before, during, and after a ride is a common strategy. How much to reduce it depends entirely on you, the intensity of the ride, and your individual physiology. Some riders cut it by 50%. Some cut it more. This is something you figure out through careful experimentation on shorter training rides, not on the day of a 60-mile group ride.
Know your on-the-bike insulin-to-carb ratio. You still need to eat. You still need carbs. And if you're on a pump, you still need to bolus for those carbs. But your ratio on the bike is very different from your ratio at rest. Personally, mine is about a third of my normal I:C ratio. Yours may be different. The point is that you need to know your number before you clip in.
Your CGM is your best friend. If you're wearing a continuous glucose monitor, you have a real-time view of where your blood sugar is and where it's headed. Use it. Check your trend arrows before eating, before bolusing, and especially before hitting a climb. A downward arrow on a hill means you need to eat now, not in 10 minutes.
The T1D riders I've coached who have the best rides are the ones who treat their diabetes management as part of their training, not separate from it. They test their fueling strategy on every training ride. They know their numbers. They carry glucose tabs or fast-acting sugar in an easy-to-reach jersey pocket. And they are not shy about telling the group they need to stop. Nobody on this team will ever give you a hard time for managing your health. That's literally why we ride.
Your increased insulin sensitivity doesn't end when you get off the bike. Many T1D riders experience lows for 12 to 24 hours after an intense or long ride as the body works to replenish glycogen stores. Keep your exercise mode or a reduced basal running after the ride. Monitor closely. Have a recovery meal. And keep checking through the evening and overnight. This is not the night to set it and forget it.
A Few Final Notes
Your gut is a muscle too. If you've never eaten while exercising, your digestive system might protest the first few times. This is normal. Start with small amounts on shorter rides and build up. Your body will adapt.
Don't experiment on ride day. Whatever you plan to eat and drink during the big ride, practice it on training rides first. The last thing you want is to discover that a particular gel gives you stomach cramps at mile 50.
Set a timer. Seriously. When you're riding in a group, having a conversation, enjoying the scenery, it's easy to forget to eat and drink. Set a recurring timer on your watch or phone for every 20 minutes. When it goes off, take a sip and eat something. It's a small habit that prevents a big problem.
If you feel it, it's already too late. By the time you feel hungry or thirsty on a ride, you're already in a deficit. The whole point of a fueling plan is to stay ahead of it. Eat before you're hungry. Drink before you're thirsty.
You are training for a 100-mile ride. You are not toughing it out. You are managing your energy like an endurance athlete, because that's exactly what you are.
Questions about nutrition or fueling plans? Reach out to Coach Jon anytime.