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Metabolic Fueling Simulator: Carb Burn & Nutrition Strategy
Personalised Carb Burn & Nutrition Strategy for Cyclists & Triathletes
Are you tired of "bonking" during high-intensity efforts or suffering from GI distress because you over-fueled? The Metabolic Fueling Simulator uses the advanced Mader-Heck metabolic model to calculate your specific carbohydrate and fat oxidation rates across your entire power curve.
Unlike generic nutrition calculators, this tool looks at your unique Anaerobic Work Capacity (W') and Aerobic Ceiling (VO2max) to simulate how your engine actually burns fuel. Whether you are a "diesel" endurance rider or an explosive "puncher," you’ll get a personalised grams-per-hour fueling strategy for your next race.
How to Use This Tool
To get the most accurate results, you will need two specific metrics from your power data. If you don't have these yet, use our specialised tools to find them:
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Find Your VO2max & W': Use our free Power Analysis Tool to find these values. This calculates your aerobic ceiling based on your best 5-minute power effort and W' (Anaerobic Work Capacity) in kilojoules.
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Enter Your Data: Plug those values along with your weight into the simulator below.
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Set Your Target Power: Type in the average wattage you plan to hold for your upcoming race or event.
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Download Your Plan: Generate your fueling report to save to your phone for race day.
How do I calculate carbohydrate burn for a long-distance cycling race?
To calculate your specific carb burn, you must know your metabolic efficiency. This is determined by your Aerobic Capacity (VO2 Max) and your Anaerobic Work Capacity (W’). Our Metabolic Fueling Simulator uses these metrics to estimate the "crossover point" where your body shifts from burning predominantly fat to burning carbohydrates. By entering your target race wattage, you can determine exactly how many grams of carbohydrates you need to replace per hour to prevent "bonking."
What is the difference between Fat Max and the Metabolic Crossover point?
Fat Max is the specific intensity (heart rate or power) where your body is burning the highest absolute amount of fat per hour. The Metabolic Crossover point, however, is the intensity where your energy contribution from carbohydrates exceeds that of fat. For most endurance athletes, the goal of training is to shift both points to the right, allowing you to ride at higher speeds while sparing glycogen stores.
Can I use W’ (W-Prime) to predict my fueling needs?
Yes. In modern power-duration modeling, W’ (measured in kilojoules) represents your anaerobic work capacity. A higher W’ usually indicates a more glycolytic (anaerobic) engine, which typically leads to a higher rate of carbohydrate combustion even at sub-threshold intensities. By using W’ as a proxy for VLamax in our simulator, you can get a highly accurate fueling strategy without the need for invasive lactate testing.
Why should I train my gut for high carbohydrate intake?
Even if a simulator predicts you need 100g of carbs per hour, your digestive system may not be able to process it immediately. "Training the gut" involves gradually increasing your carbohydrate intake during long training rides to improve absorption rates and minimize GI distress. Most athletes can process 60g/h, but elite performance often requires 90g–120g/h, which is only possible through consistent nutritional training.