Sorry Airbanda, but you are wrong. Fasting does not inevitably result in a low blood sugar, but it certainly can. In the last decade I have seen two surgeons in the NHS 'collapse' whilst operating during Ramadan. Whether the skills of others were diminished is harder to determine. Imans have repeatedly told both doctors and patients they should not fast.
Personally I would not fly if the pilot was fasting, if only i could find out......