Perhaps this is better suited for CivFanatics, but I rather think we have the better deep analytical minds here. 
I'm trying to wrap my mind around an apparent paradox involving the health cap and food. When a city is over the health cap, each extra population point costs 1 extra food to support. So if you raise the health cap by 1, you essentially add (recover) 1 extra food. This seems to mean that, to add one citizen to an unhealthy city, you need 3 health factors to provide the 3 food needed to support him.
But logically, there should be a 1-to-1 correlation between health factors and city size. If you add 1 health factor, the entire city can be 1 size larger before you run into any health problems.
So what am I missing here? Is the true correlation between health and city size 3-to-1, or 1-to-1?

I'm trying to wrap my mind around an apparent paradox involving the health cap and food. When a city is over the health cap, each extra population point costs 1 extra food to support. So if you raise the health cap by 1, you essentially add (recover) 1 extra food. This seems to mean that, to add one citizen to an unhealthy city, you need 3 health factors to provide the 3 food needed to support him.
But logically, there should be a 1-to-1 correlation between health factors and city size. If you add 1 health factor, the entire city can be 1 size larger before you run into any health problems.
So what am I missing here? Is the true correlation between health and city size 3-to-1, or 1-to-1?