I haven't yet done much research into 5:2, so forgive me if I sound a bit stupid! I thought here would be a good place to ask.
I understand the general premise is eat normally for 5 days and fast (approx 500 cals) for 2 non consecutive days. But I'm not entirely sure what is meant by eating normally, presumably it means fairly sensibly, but not depriving yourself of all treats.
I just wondered how the 5:2 way would deal with bad days. Say I was going out to a fancy restaurant (the sort that serve amuse bouchée so you end up with 7 courses or something silly of all rich food), would you do a extra fast day to counteract? Or if you just ended up scoffing loads on a non-fast day, is that ok with this diet, and the fasting days counteract it anyway, no matter how much you eat?
IME there's no such thing as a stupid question - pound to a penny someone else has the same question and is checking this thread for the answers!
The answers to your questions are all to be found in the OP of the main threads - nr 36 is the current one. It's an absolute mine of information, and if you read that, and follow all the links, you'll be fully up to date with this WOL (Way of Living!).
You're right about the eating sensibly bit - check out your TDEE on the calculator to be found - you guessed it - in the OP of thread nr 36.
I'm maintaining now, and if I was to find myself in that fancy restaurant I would either skip breakfast and lunch beforehand - or not eat breakfast the next day (known as a 16:8 - fast for 16 hours, then eat in an 8 hour window). Or even have no breakfast or lunch, in which case that's a 24 hour fast.
This WOL is so flexible you can twist it or turn it to suit yourself.