why doesn't this script work? [couldn't think of a better title]

It's because it will only run the code once, so it will only do everything you said once. You can put it in a loop so it checks "Hunger" more than just once but forever! Like this:

wait(1)
print("FOUND IT")

while wait(1) do -- the 1 can be changed to anything, it is how much it waits to repeat the loop in seconds, 1 would mean it would do this every second.
	
if game.Players.LocalPlayer.leaderstats.Hunger.Value <= 10 then
    e = true
    print("1234")
    while e do
        wait(2)
        print("UGH")
    game.Players.LocalPlayer.Character.Humanoid.Health = game.Players.LocalPlayer.Character.Humanoid.Health - 10
    end
end

end

--[[if player.Character.Humanoid.Health <= 0 then
    e = false
    --]]