I am intermittently fast.
On a more serious note, I am dubious as to the health benefits of fasting unless you go on a longer fast, so as to introduce some autolysis. I would also avoid doing much more than easy spins during it and expect to lose quite a bit of form.
I would prefer something like a Gerson treatment program where most food is replaced by fresh juice.
I just cannot see it being beneficial to a racing cyclist, unless you were planning to take time off anyway.