Even if brain uploading becomes common, some food would still be needed to maintain the bodies of those responsible for population growth and nurturing the young until they are mentally mature enough to be uploaded. Because it's highly doubtful immortality would be sufficient to keep us from having kids, especially when the stated goal of the cybernetization is to allow spreading all across the galaxy.
If brain uploading is common, you don't need biological people at all for population growth.
Build a new server, make copies of all the brains on the old server, population doubled.
(if you want different people, then have an algorithm that generates a semi random brain simulation. if you can simulate an actual brain, you can simulate a madeup brain)
Basically once you have brain uploading, you should be able to build population with production, and sustain it with energy.
(giving those as options..ie "population growth" as a thing you can build that puts production into the food box.... and anytime your food supply is too low it subtracts from your energy supply (so no starvation as long as you have energy reserves)
Then, as farm boosts would be in Purity and Harmony techs/buildings, you would slowly replace all the farms with generators and mines.