How many carbs per hour for cycling, by Bidon

Most cyclists carry the same energy bar and bottle for every ride, regardless of whether they're climbing steep grades or cruising flats. The result: bonk before the finish, or carry food they never needed. The real answer to "how many carbs per hour do I need?" isn't one number, it changes with terrain, intensity, and duration. Bidón, the free Garmin Edge app, calculates your exact carbohydrate requirement every hour so you eat what you actually need, when you actually need it.

Why carbs per hour matter in cycling

Your muscles burn roughly 200–300 kcal per hour of moderate riding, and carbohydrates are your primary fuel source during endurance efforts. Sports nutrition research, particularly the work of Professor Asker Jeukendrup, shows that optimal carbohydrate intake directly correlates with performance and fatigue resistance. Ride too long without enough carbs, and your liver glycogen depletes, that's the bonk. Eat more than you can absorb, and you risk GI distress.

The challenge is that your caloric burn isn't constant. A steep climb demands more energy than a descent or flat stretch. Wind adds invisible energy cost. Ambient temperature affects sweat rate and digestion. A static fueling plan ignores all of this. Bidón recalculates your hourly carbohydrate need in real time, segment by segment, so you're never guessing.

Jeukendrup's carbohydrate guidelines: the science behind Bidón

Jeukendrup's research, now adopted by sports nutritionists worldwide, establishes carbohydrate intake ranges based on effort duration:

• Under 2.5 hours, low intensity: 30–60 g/hour (mouth rinsing may suffice for short efforts)
• 2.5–3 hours, moderate intensity: 60 g/hour
• 3+ hours, variable intensity: 60–90 g/hour (depending on individual tolerance and intensity peaks)
• Ultra-endurance (4+ hours): 90 g/hour with multiple carbohydrate sources to maximize absorption

These aren't arbitrary numbers. They're derived from the intestinal absorption limit (roughly 60 g glucose, up to 90 g with fructose blends) and the fuel demand of sustained aerobic work. Your body can only absorb so much carbohydrate per hour; exceed that, and undigested fuel sits in your stomach.

Bidón uses these frameworks as its foundation but adjusts for your specific route. If your segment demands a sudden 400-watt climb, your carb need spikes. During a descent where you're coasting, it drops. This dynamic calculation is where Bidón differs from a static fueling plan or a generic nutrition app.

How Bidón calculates your hourly carb requirement

Bidón works from what is happening under your legs right now, not from a route file. It looks at how long you have been riding, how hard you are going, the temperature and the bottles you told it you carry, and moves your hourly target inside the Jeukendrup ranges as the effort changes. It does not download your route and it does not read a wind forecast, so a climb and a headwind are the same thing to it, more watts.

The result: alerts on your Garmin that tell you not just "eat now," but roughly how many carbs (in grams) you need. No guessing, no one-size-fits-all bar, no bonking halfway through because your fueling plan assumed flat terrain.

You can also integrate this with MoguWind Plan, the web route planner. Import your Strava route or draw your own, and the planner shows you wind direction and speed segment by segment, plus the interactive map reveals which climbs or exposed stretches will demand the most energy, and therefore more carbs.

Practical example: what Bidón actually tells you

Imagine a 4-hour ride: 50 km of rolling hills with a 6 km climb in hour two, headwind in the last 30 km. Here's how Bidón's hourly recommendation might look:

• Hour 1 (rolling, 200 watts avg): 50–60 g carbs
• Hour 2 (includes 6 km climb, 280 watts avg): 70–80 g carbs
• Hour 3 (rolling, headwind, 240 watts avg): 60–70 g carbs
• Hour 4 (steady flats, 200 watts avg): 50–60 g carbs

This isn't made up; it's derived from your elevation profile and route characteristics. Bidón then delivers these alerts in real time on your Garmin screen so you can adjust your intake without pulling out a notebook or calculator.

Beyond just carbs: fueling and hydration together

Carbohydrates don't travel alone. Jeukendrup's broader work also addresses sodium, fluid intake, and the interaction between carbs and hydration. Bidón factors all of this: the app suggests not just carbs but also drink reminders, accounting for sweat rate and environmental conditions. A hot day on a climbing route demands both more carbs (effort) and more fluids (temperature). Bidón calculates both.

This integrated approach prevents two common mistakes: dehydration (which itself impairs carb absorption and increases bonk risk) and oversaturation (drinking without carbs, which dilutes sodium and can cause cramping on long efforts).

How MoguWind Plan amplifies Bidón's fueling strategy

MoguWind Plan complements Bidón by letting you preview your route's wind balance and elevation before you ride. You can see exactly where headwinds or climbs cluster, so you know which hours will demand peak fueling. Plan your nutrition strategy at home, then let Bidón execute it on the road with real-time alerts tailored to that specific day's weather.

Getting started with Bidón

Bidón is free and works on any Garmin Edge device via Connect IQ. Download it, sync your route (or build one in MoguWind Plan), and the app will generate hourly carb recommendations based on Jeukendrup's science and your actual route profile. No subscriptions, no guessing, no bonking.

The key insight: carbs per hour isn't a one-size-fits-all number. It's a function of terrain, intensity, and time. Bidón does the math so you can focus on the ride. Get Bidón free on Garmin Connect IQ today, or visit bidon.moguwind.com to learn more.