Possible, this means you were already eating very close to your TDEE, all you needed was to slash off a few calories (which you burned cycling) to be on a caloric deficit. Plus the cycling sped up your metabolism enough so that your body at rest also burned more calories. This is how you lost weight.
Doesn't work for everyone cause most out of shape people eat far above their TDEE, and simply don't exercise enough to burn enough calories to cut away that surplus and get into a deficit.
To save others Googling — "Total Daily Energy Expenditure": your Basal Metabolic Rate (BMR; i.e. energy used up at rest) + calories burned through any activity (exercise).
Doesn't work for everyone cause most out of shape people eat far above their TDEE, and simply don't exercise enough to burn enough calories to cut away that surplus and get into a deficit.