Food & Population Cap

I've only been playing around, so not 100% sure, but it seems that spare food does not spread around.
The basic pop. cap for a planet is just 5B+1B for every MT of food produced on planet. The advantages of high pop seem to be:
More taxes from planet
If you you don't have enough pop to operate your buildings, they work at fractional strength (Not sure, i think number might be 1B/building)
More Defensive soldiers when a planet is assaulted.

The main disadvantage from high pop is that it makes the people unhappy (I guess 30+ B people on one globe is a little crowded), which reduces your popularity.

actually the pop cap is determined by the quality of the planet. It doesn't matter how many farms you build, the pop won't go above the cap thats determined by the planet quality. A formula was posted by someone from stardock that will figure out the exact number of pop that your planet will cap at.

Here you go:

Limit = 20 * ((Q+1)^3)

So for a 19 quality planet the theoretical limit would be 1600B? That seems... excessive.

The food is per-planet, which seems kind of unfortunate. The pop-cap, as I've seen, depends on your food production. Colonies naturally start out with 5MT, and capitals with 10. There's apparently 1B people for 1MT of food, so it's not too hard to figure out.

That is, if I havn't gone completely looney.

So for a 19 quality planet the theoretical limit would be 1600B? That seems... excessive.

AFAIK the maximum on any planet with any PQ is 100B

PQ has nothing to do with PopCap. You can look at the planet screen and see how much food you are producing. To the right of that is a box showing planet population. Building run at the efficiency you set them at in your government window. It doesnt matter how many people you have. I have had a planet down to 5 million, yes million, people and still run the buildings at whatever efficiency I determinced from my tax and distro screen (f4). The only way to increase the pop cap is to build a farm. The farms produce varying amounts of food in megatons (mt) depending on your technology. Farms are a waste in the game. Dont build them unless you have a farming bonus square. The capital of your home world and the colony capitals produce enough food for 10billion, capital, and 5 billion, colony. Farms take up space for other more important spaces. They are only worth a wasted space if you get a bonus. Again, for those commenting you havent played the game. PQ has nothing to do with pop. and pop has nothing to do with efficiency.

Hope that helps the original poster. Sorry if you were confused by the others in here. The formula that the guy above is speaking of is a hard limit. No matter how many farms you build you cant go above it. You still have to build farms to get above the 5billion and 10billion limit. I am playing v1.D1.008

Brighton's observations on the population cap match mine, but I disagree with his conculsions on the usefullness of farms. Find a good planet with no farming bonuses and you're capped at 5 billion. A basic farm bumps that up to 9 billion. People = taxes, and you need tax revenue to turn production capacity into social and military projects (buildings and ships).