Why isn't this city growing?

[herald]

I have extra food, and the people are not unhappy - What gives?

 

[Ranos]

In Civ 4, when you build workers or settlers, the city stops growing and applies both hammer and food resources to the production of the unit. That city is building a worker so it won't grow until the worker is completed.

 

[jeffelammar]

You are building a Worker. That consumes all food and converts it to shields toward the worker.