The amount of sugars and bodyfats you burn during cycling depend on the Heart Rate (or power) zone you train in. In our freemium app we estimate your zones based on a standard formula, in our premium app you can also set them.
Setting your zones will make the nutrition planning more accurate, standard formula results can be inaccurate.
It is also important to know your fitness level, usually known as your VO2Max.
The higher your vo2max the more energy you can burn but also the more energy you can burn from your bodyfats.
Having a high VO2Max helps you to burn less sugars and extend your energy since you will usually more burn than you can consume during rides.
If you don’t know your VO2Max you can find a clinic to do a lab test. Also some head units can give your a fair estimate like your Garmin.