The RFL is a modified Body Opus I believe. Do your strength work after any carb reloads earlier in the week, as later in the week you won't have the energy to do much of anything but walk on the treadmill for 45 min. Metcons would be disastrous. Caffeine and B12 will be your best friends.
It can work....but it is brutal. You can still lose weight without needing to go that extreme though.