Prototype

This is actually quite simple. There are so many military personnel and various types of infected that you should never need to consume any civilians. You can tell the difference between civilians and infected civilians (who can be consumed without consequence) by looking at their appearance and behavior. Civilians look like normal people, and will generally ignore you or run away from you. Infected civilians look and move rather like zombies, and will run towards you to try and attack you. Please note that civilians who are Web of Intrigue targets are not counted against you either.

You can track your progress under the Statistics -> Consumes page on the pause menu (listed as "Pedestrians Consumed").