So where can I find out what my region actually consumes or is the 99 value per week or something? Because I don't want to ask for food until I know exactly how much of a deficit I apparently have.
The 99 value is per week, as mentioned. However, it takes into account only the
peasant population - any troops in the region will eat extra (although it is normally a smallish amount that shouldn't have that much effect). My theory on this is that each soldier counts as one extra peasant, and eats the same amount as a peasant would.
If you want to get a good idea of how much is
actually getting eaten, check your warehouse every day and see how much was taken out for that day. I believe the food is taken out at the morning turn for that day (logically).
This is just adding on to what has already been said, not contra to it