You need more and more food as you shift focus towards military. A full zerk castle requires 75k/hr food, a full knight castle can eat up to 150k/hr.
The maximum food/hr a food city can produce is a little over 174k/hr, and it looks like this. This would require that you have a landlocked city surrounded by plains (not mountains, hills or forests.) This will give you the maximum amount of lakes, which is 10. The lakes will also need to be in exact positions of the layout. You may notice that there are no purification or shipping mechanism, which is not realistic of an actual food city.
Typical food cities will look something like the examples below. These are 3 of my actual food cities. The first 2 are landlocked, the third is a water city, which understandably, produces less than the other two.
How to build
The city below is a typical layout of a food city without any lakes. This guarantees production of 143k/hr. If your food city produces less than 143k/hr, you must have a mistake somewhere. Add in lakes and modify a bit to get over 150k. It takes practice to get the optimal layout. If you are not sure, post a comment and i'll try to optimize your food city.
- Demo all natural resources except lakes
- Upgrade townhall to lvl 4
- Build 40 temp cottages and upgrade to about lvl 6 or 7
- Upgrade townhall to lvl 10
- Build out your city, make sure to include the marketplace and moonglow tower
- Once all permanent buildings are at lvl 10, demo the temp cottages and replace with a permanent building