I'm not sure I understand your question, so let me supply a bevy of info and you can decide if I answered it. One note, since my original post, the food WASTE has returned to normal in my capital, but now New York, my 5th city, is taking off, so I will use that as my Exhibit A.
New York: size 68 - will grow in 3 turns
+126
from Worked Tiles
+228
from Trade
+109
from buildings
Base
=458
+44% from buildings
+36% from resources
+10% from civics
Total
produced =879
Consumed
-204 from population
-72 from waste
-2 from health
Net
+601
Minneapolis Size 45
+149
from worked tiles
+59
from trade routes (major discrepancy, I know)
+117
from buildings
base
=320
+49%
buildings
+29%
resources
+10%
civics
Total
produced= 611
Consumed
-135 for population
-371 for wasted
Net
+105
What you've got going on there is that New York has a larger population than Minneapolis, therefore there is less waste. The system and numbers make perfect sense, even if they're difficult to understand at first.
You need to think of population growth differently. Try thinking of it as a percent. Each time a city grows, it adds a single population unit to the total population. However, that additional person represents a larger PERCENT increase in population size over a given amount of time for a smaller city.
For instance, if a size 2 city grows to size 3, that's a 50% increase in size. On the other hand, if a size 20 city grows to size 21, that's only a 5% increase in size...
So you would expect, with the same % growth a year (and there *IS* a limit in real life to how many children each generation can give birth to and raise...) that the size 2 city would take 10x as long to grow a single step if it were growing at the same percentage rate per year.
Let's compute some numbers shall we:
New York: An increase from size 68 to size 69 represents a 1.47% increase in populations size, first of all.
If you're at the point in the game where a single turn represents a single year, than that means you have a 0.49% increase in population per year.
Human populations have a generation time (time between when a child is born and when they have children themselves) of approximately 25-35 years in modern times, so let's take the low end (humans had kids at a younger age earlier in history) and assume they're having kids by age 25 on average...
0.49 * 25 = 12.25% (per generation)
This means, each woman is having, on average, 2.245 (2 * 112.25%) children by age 25 who survive to have children themselves. Not a terribly fast rate of growth, despite the short growth time (only 3 turns). There are simply a lot of childbearing women in the city of New York.
If you use a longer generation time of 30 years...
0.49 * 30 = 14.7% (per generation)
Then each woman is having, on average, 2.294 (2 * 114.7%) children by age 30 who survive to have children themselves. Still not a very fast rate of growth. In fact, New York could grow EVERY SINGLE TURN (1 turn to grow), and each woman would still only be having 2.882 children by age 30 who survive to have children themselves, on average.
Minneapolis: An increase from size 45 to size 46 represents a 2.22% increase in population
Since the food required to grow increases exponentially with each increase in city size, and Minneapolis is about 2/3 the size of New York, then it should only require about 4/9 the food to grow of New York.
If New York is growing ever 3 turns with (approximately) 600 food production, then it should be requiring about 1800 food to grow (this is after the effect of buildings like granaries).
Therefore, Minneapolis should require about 800 food to grow.
Minneapolis should currently be growing about once ever 8 turns, at a surplus of 100 food a turn. Compared to New York, it is growing at a bit over half the percentage rate a year.
As before, if 1 turn = 1 year, then Minneapolis would need to grow every 4.5 turns in order to grow at the same rate as New York.
However, Minneapolis' food surplus before waste is only about 70% (476/675) of New York's, so it should grow at a slower rate...
Minneapolis is growing at 50% the rate of New York, but has a surplus that is 70% the size.
That sound pretty reasonable to me... Perfectly in line with exponential increases in growth rate with increasing surplus.
And I'm working off the numbers you gave- which I'm guessing have New York growing in 3 turns based on current food stores, not every 3 turns in absolute terms... I wouldn't be surprised if the difference in growth-rate is even less drastic...
Of course, I don't know how much food each city has stored, or what % they are keeping after growth. But I hope you can see that the numbers DO work out in the end.
Regards,
Northstar
