Instead of basing it on how much food we have, why not base it on our ability to produce food? So instead of requireing obscene amounts of stock food, have it something like if number of farmers x sq acreage of tilled fields = x, then a new hearthling is available.
So, add yet another punishment for those who live if berries? I don’t dig it, personally.
Also, don’t forget that food is also produced by Trappers. I see where you are coming from @Communistpenguin but I don’t think it would work just with a fields/farmer calculation. Berries and trappers would have to be included.
Personally, I feel that the current system (gold value of food in stockpiles) works okay, but perhaps needs balancing. The addition of a cook specialism will likely offer new foods with higher gold value which will help balance this out anyway, I should think.
As has been mentioned before though, lowering this requirement now would mean you would get new Hearthlings too fast - the game can only handle so many at the moment.
You are forgetting about food from the trapper (and future advanced class versions of that) at a minimum.
And what about when you buy food from a trader?
Are you really going to attract more people with uncooked food? The cook is coming!
There may also be a brewer job eventually, because who wants to live somewhere without beverages?