What is a way to make a sustainable food source early game?

Considering how it takes at least a month for most veggies to grow but you can only last 4 days without food (when well fed with a standard metabolism) it seems like meat is only the real sustainable resource. I know there is plenty of food in the forest come summer/fall, but considering most scenarios start in winter/late spring, most survivors don’t make it long enough to see summer since by then they’ll either starve or get killed by mutated zombies
However even then meat begins to be unsustainable as many creatures eventually mutate/become infected, and then become poisonous and/or less calorically dense
And of course the shelter won’t sell you food either, since they can barely feed themselves

Does anybody know any good ways to keep a stable income of food early game, without having to travel long distances?

Find a swamp. Cattail rhizomes are 280 kcal(?) each. Use the mutant meat to craft fish bait, use fish traps to catch fish. Some fish will give you over 80 fillets at high survival skill.

Raid houses for more food than you’ll ever be able to eat.

I think you missed the point of “travelling to far”, and especially the part about “not entering cities that are complete deathtraps”

“Travelling to(o) far”? What is “too far” exactly? 10 squares, 64 squares? A whole Map Tile? Unless you have Spacing between cities at 16, you’ll always see a small settlement that you can raid at night, regardless of what’s roaming about. Literally raiding buildings is the best thing to do, especially with the canned / preserved stuff. Eat the stuff that’s expiring first, leave the “sealed” stuff for emergencies.

Get MREs.

It’s all circumstancial: what’s the specific scenario, what’s your character’s condition, loot modifiers, monster evo rate, starting date, etc etc etc. There’s no “1 formula fits all scenarios” miracle, unlimited food source.

As mentioned already, it depends on your situation.

  • Early on:

    • What you can find in isolated houses/ones at the edges of small settlements where you can sneak by the zombies.
    • What you can find in the wild, including an occasional incredibly stupid small animal that only stands there while you’re wildly swinging something trying to hit them.
  • Mid term:

    • Hunting (and fishing is probably even easier) for meat that can be preserved.
    • Farming
    • Gathering from the wild
    • Looting houses in areas you’ve cleared. Perishables may be gone, but there’s a lot of preserved stuff.
  • Long term:

    • More looted preserved food in a larger radius.
    • Farming
    • Farm animals (enormous hordes of chicken build up, and I’ve found more horses, cows, and sheep that what I care to collect, but only two non zombiefied pigs that are contained such that piglets might be tamed, should they eventually produce any).
    • Milk from cows and sheep. Good stuff for your nutrient balance. Milk into a bucket, treat the raw milk, and then toss it into a freezer (you’d have freezers in the long term case) to drink one bottle a day. Repeat when you run out of milk.

The above is valid if you’re settled. If you play a nomad you’d have to scavenge from what used to be civilization as well as from the wild.

Welcome to the Hunter Gatherer Dilemma of life. You can forage, or hunt, or go kill to get some zombies old food stock. If you don’t want to have to travel a great deal, then only make the trip once. Set up base near an area with abundant food, like a swamp.

Really, that’s the solution. Agriculture is the method you need to set up a base first, and food second. If you can’t last until that harvest, then you need to go where the food is.

I’ve managed to spawn near a large lake (cattails on the banks), with multiple swamps nearby. There’s probably enough cattails here to last me the 90 days for my cattails plantation to be ripe for harvest. Failing that, I have about 100kg of meat preserved. I am one month and a half into the game and hope to plant over 5000 cattails before summer ends.

just find or make a fishing rod and start fishing is litterally the easiest way to get food and can be done with any body of water larger than a puddle in the forest.