I don't think i like the OP idea because of how random the game makes those type of resources and how you can become crippled if someone comes by and destroys it. I do not mind how food is made atm but do see other problems with it.

1. There needs to be a penalty for going below 0 global food. This would stop you from destroying your own farms after you finished building all the cities you needed and also discourage putting all your food in one farm planet (if that planet got captured you would be crippled until you got it back or rebuilt.) Maybe add a bonus for having extra food so it doesnt become useless once you have all you need.

2. I play some games where resources are a non factor because of how common they are and other games where i cannot build things because the resource just doesn't exist- like advanced farms. All resources need to be built into the map builder based on the number of players in the game or the number of planets depending on how the resource is used (a slider to make them rare or common would be cool). You'd have to make it factor in the races used too on second thought since different races use different resources.

It really should be called Surplus food instead of just food tbh.

Place holder.  (I have an idea,  but am on my phone)

Some other thoughts.

My planets seem to get enough pop cap with one or two cities and I can get that done by the Age of War. Farm tech beyond that isn't all that great since I don't need the food and often don't have the resources anyways.

I'd like to see farm tech in the Age of Ascension or maybe even earlier focus on changing the types of food grown to add to your manufacturing/research/weapons/soldering ect rather than the amount of food grown. Food distribution trees should be replaced with advanced city designs that would not increase pop cap but add different bonus like I suggested for farms. This would add more thought to where you put farms and cities beyond +pop bonuses.

I love the different tech trees you get on races and especially the special buildings they can sometimes build. I think its the aquatic races that unlock different hydroponic farm tech and would like to see that change to be more distinctive from the standard trees other than hydroponic farms produce 3 base food.

Overall the change proposed by the OP feels like planet development would have farms removed and the tiles instead used for more of the same- factories or maybe research labs.

Yes but the current system is hampering the AI. Again abstracting (most) of the farming involved... Truly simplifies the issue of AI which now just needs to think about placing City hugs and grabbing farm techs so it can build bigger or better cities.

Notably, to support "tall" empire building, those farm techs could unlock bigger bonuses to existing cities as well... Possibly through upgrades . 

If so empire have expanded or knows it's smaller in terms of colonies than the average empire for the last 20 turns, it could priortize techs that upgrade it's existing cities and such .

Thematically: I would like to think that "food" is a solved problem for advanced galactic civs of the future.

Strategically: if the only thing food does is limit your pop cap, that is not an "interesting choice" and the entire mechanism should be removed. Otherwise food needs to be useful for more than just one thing.

Yep, definitely food needs to impact on several things:

Population: Whichever you need to grow the population of whichever of the four species you are, I think the four "things" should work the same way or as close to it as possible without being too gamebreaking. The ultimate simplicity, of course, is to just have four types of farms for each of the species and have them produce food/Durantium/new person/whatever that race needs. This immediately does away with the possible curse of a galaxy with no Durantium or whatever. Surely if population and productivity is 1/1 all four species as I understand it, that seems a fair solution for Population growth.

Obviously, it might be better to buff up a certain species in a different way or there may (I've only played carbon) be an existing advantage in a different area for that species that compensates for slow population growth/population growth relying on something rarer than food, I just see this as the quickest way of solving that issue.

Morale: Hungry people aren't happy people. As morale goes down, resentment of your civilization's government goes up. Also, maybe the morale takes a hit because a planet's leaders - or the civilization government - are buying food off the black market to feed their fellow folk. And it's a seller's market always and the quality's bad but it's eat garbage or starve.

Wealth: See above comment on food black market. It's a seller's market so you're paying over the odds for food. To feed the hungry people who are too hungry to work/produce. Therefore no work = no tax/income for the planet. A planet/civilization can't produce the bigger, fancier ships, farms, factories etc because of the lack of money.

Influence: Is that planet owned by that other race really going to culture flip to a planet that's suddenly got no food and is poor and miserable about it? Planets culture flipping to another planet is more likely as well.

My thoughts: Current system seems ok with some adjustments.

Planet should have base food production, which supports a base population, for example we won't live on mars till we can produce food on mars.

Planet Type should influence how much food can be grown on a planet. A desert planet will likely have much less food than a lush planet. i.e. fewer people live in a desert than in a lush environment. So a desert planet will have a lower base population than a lush planet. 

Planet size could play into this base factor as well. A small lush planet will likely produce much less food than a larger one.

• Base Farms increase food production
• Planet resources used as currently do (build better farms).

One thing with "resources" being required for different improvements, it would be nice to see variance in them. For example you can have run a factory with Coal (resource), or nuclear power. Two different resources for improvements. Though clearly they have different effects on said production. 

So in the tech tree, easier(earlier) techs require none or easy to get(abundant)  resources. while later techs require more rare resources. This would prevent the problem Taslios mentions in not being able to build an improvement because no resources. Everyone should be able to build easy/low tech improvements with easy to get resources, while the later techs require harder (rarer) to get resources.

One thing I don't like about the the current resource implementation is that mid to late game most resources become worthless. This may be a trade issue, but sitting on 1000+ of a resource is like why do I even bother? Only the few space bound resources (i.e. antimatter, etc) seem to be of any value and even then Thulium, compared to others seem much less valuable.

So using ideas above, coal plant or solar power. Two different types of of resources. If I only have coal I will use that, which could be bad for planet (moral, or other impact), while solar power would be better.

How about all unused tiles produce food (a variable supply depending on the tile and/or planet type) as long as you don't build on them. Some improvements could increased the food they produce.

So basically, almost everything is arable land, to some degre. Just like in real life, actually. Settlers can do basic farming on every tile of the planet, as long as there isn't infrastructure occupying the place. Then, some buildings can represent the infrastructure needed to produce greater amounts of food.

I really like this.

I think it would be good to include a global mechanic that Food Deficit = starvation = population loss.       Those Farming planets are great, but if you lose them you should suffer big time.

So the biggest change is that Cities and Megalopolises should not cost food to build. 

Population should be dependent on food supply.    Cities only allow your population to grow larger.

I would also add that upgrading the basic farms should use Thillium or Promethium or one of the "space" resources while the hub buildings use monsantium or unique stuff.   You don't need the hub buildings, but the current system is so very unbalanced.

I do still often see AI planets stalling in development for a long time with empty tiles and no food for cities. If those tiles just defaulted to farms the AI could get started far easier.

The Wild Grain tile/adjecency bonus would make more sense too. If there's wild grain, why do I need to build a big sci-fi farm to eat it? The wasteland tile bonus should definitely be foodless.

The original plan to change food was frankly the first proposed change to the game that I wasn't happy about and I preferred the status quo. However this idea has my full support.

I'm cool with the food system as it is; but I think its too Monsantium dependent.  Monsantium isn't super common and its required for every food upgrade beyond the basic farm.

I also think adding orbital farming improvements (as well as morale boosting improvements) might be a nice upgrade for Influence starbases to make them a more viable alternative to economic starbases.