What is the troops consumption rate....?

Troops that you have trained will use up resources (food and lumber) and the more troops you have the higher the consumption rate will be.

If your consumption rate goes above the production rate for your resource buildings then you will use up the resources that you have.

The game has a minimum level though for food and lumber that if you go below then the consumption will stop. This level will depend on your castle / base level.

When you are below the level there is no consumption and your amount of resource will raise with your production rate. When you rate the minimum level consumption will start again and you will remain around this fixed point until you use up resources or gain some from gathering / raiding etc.

This does not affect resources stored in the inventory in the reward chests. These are safe until you use them.