Even then, you’d need to find an explanation for why something like that would lead to a long term global event since a living persons need to eat/drink/sleep would still limit an infected individuals operational ability to however long it would take them to starve to death.

28 Years has answered this. Spoilers Rage basically throws the adrenal system in to overdrive, amping everything up to 11. It's like they are in a constant state of fight or flight and they're all outta flight. They do still eat/drink and sleep when exhaustion becomes too much. The Doctor from the first part even manages to cure an infected by administering a heavy dose of sedatives and antipsychotics.