It's not a glitch. Cities need a minimum food supply; beyond that, the option to switch between farmers (to support troops) and workers (to increase production and/or housing) is based on your needs and playing style. If your available food per turn reaches -1, troops will disband; unlike with mana, you cannot maintain a food bank while running a deficit.

As you grow your cities or conquer new ones, you'll also run into rebels, who (just like your best friend from college) eat all your food while contributing nothing to the bottom line. The best way to reduce those is to build more shrines, etc. or cast city enhancement spells to pacify them (most of which are Life or Nature, as you might expect).

Welcome to the party. Now go forth and have fun.

Thanks for your reply!
So every city needs a certain minimum amount of food that does not depend on your total production?
Also, why would I find myself in the situation of having +5 food and not being able to reduce the number of farmer in ANY city?

Hmm I'm new to MoM but I don't think you can go lower than 2 farmers (EDIT -this is wrong the other guys answer this)

You can also get rebel citizens, you can spot them as they throw their arms in the air, the only way to make them usable is to build things like Shrines that lower rebellion.

Normally, each farmer produces 2 food (3 for halflings). So let's assume you have 5 cities with 5 population each. Each city requires a minimum of 5 food, which means 3 farmers, and each city produces 6 food. 5 are eaten, 1 is surplus for each city, thus resulting in 5 food surplus to feed your troops.

Be also aware that extra food is turned to gold, so you can squeeze a few extra gold by finetuning your production, if you make 75 production per turn and build something that requires 100, you will waste the extra 50 production. Turn some of the workers to farmers so you still build it in 2 turns, while making a bit more from food (or increasing production in other cities).

And for the rebels, every 2 troops stationed in a city reduce unrest by one, and spearmen are a good unrest reducing starting unit.

Didn't know that about troops, gonna make the game easier for me now, I've just been deleting spearmen :O

So, if I understand what you are saying, the +5 food is in no way avoidable in that scenario because is just the stacking effect of the +1 surplus of each city, that can't be lowered as it would make that particular city starve (since the food is not shared between cities)? Productivity is only important when building something? Once all is built or when I'm just increasing the amount of population or trading I should set all to farmers?
Also, good to know for the unrest. Do magical creature work in this aspect?

One more question, while I'm at it. How come each building has it's cost in gold but I'm still able to build them without having any? I was playing a game where I was only using hellhounds and few other magical creatures (no regular armies), and I was able to max my cities even though I had no gold whatsoever (even though the up-keeping of the creatures became ridiculous).

Thanks as well to TwoHandedSword and SweatyGremlins :)

Yes. Building also counts unit creation and trade goods/housing. Since you may also need food for your armies, the required balance does depend on what you are trying to do. A highly productive city may increase its population more by building housing with workers than creating food with farmers. And when a city grows, it goes to the nearest thousand, so gaining 280 citizens while at 16980 will "waste" 260 of those, since the population will be 17000. Assuming they are garissoned in the city, yes. I assume by cost in gold you mean upkeep? Each non-rebel citizen you have pays a certain tax amount (which you can change, F7 I think?), which is then modified by the town's buildings (market, bank etc). From that amount, the buildings upkeep is redacted. Even if you have a negative gold income, you can still get by either through looting gold from dungeons/caves/temples etc, or through alchemy.

Also, right clicking on food/production/gold in the city screen should give you a breakdown of what is being produced and what is being used.

Thank you a lot, this covers every question that comes to mind at the moment :)

Actually, IIRC summoned creatures don't count toward this, or at least aren't supposed to.

I'd also like to point out to the OP that you max out at four rebels calmed with 8 troops; a ninth unit is wasted in this regard. Each building has a cost to build it (or the rest of what's needed) right away, on the very next turn. Otherwise, you build it with production points and maintain it with either gold or mana, depending on the structure.

Protip: Unless you're flush with cash and time is of the essence, NEVER build something in one turn. Waiting just one extra turn cuts the building cost substantially (think used car vs. new car); waiting until it's at least 1/3 built drops the cost even more; and waiting until it's at least 2/3 built drops the cost yet again. Note that this is building cost we're talking here, NOT upkeep cost. And the same trick applies to troops as well.

Quite possible. Haven't really used summoned units, preferring my slingers of doom for the dirty work, and the spearmen for unrest reduction.
Extra protip. Hurrying production doesn't complete what you are building, but increases production by X. So you can buy a spearman unit, then switch to settler, then to engineer, then to magician and spend less than buying the magicians outright. Could be considered an exploit though, and not sure if Insecticide fixed it.

Not sure if I follow...
Each building has an initial cost in production and an upkeep cost in either gold or mana.
Doesn't the production just add up to cover the cost turn by turn?

This I did not understand.

Let's assume you wish to hurry a High Men magicians unit. It costs 120 production, so to buy it fully you need 4 times the production in gold, aka 480. If instead of hurrying the production for magicians, you hurry the production for spearmen (10 production), you pay 40 gold and get 10 production. Change the unit to build to magicians now, and the magicians have 10/120 production, so each remaining production only costs 3 gold, so an extra 330 will create them, for a total cost of 370. If instead of magicians you switch to swordsmen (10/20), then to cavalry (20/40), then to pikemen (40/80) and then to magicians (80/120) your total cost would be 40+30+60+120+80=330 instead of the initial 480.

My numbers may be off, I recall it being 4 gold per production if no production there at all, 3 gold if some production and 2 gold if at least 50% production. It is possible that the thresholds are 100%, 66% and 33% though.

Oh ok, I get it now, I didn't even realize that you can hurry units up.

By the way, has anyone understood what the dialog is at the initial cut-scene? I just can't make out what they say!

- Old man you seek the spell of mastery
- You have come too late. My work has already met with success.
- If that is the truth, then your work must stop.
*spell casting*
- No. No