I ALWAYS take food with me, like a energy bar, at least. I live in the middle of nowhere; there are no stores anywhere on most of the routes. It's more populated here than where I used to live...
I just got in the habit when I lived beyond the middle of nowhere in Montana. We always carried food and water in the car as well as various things like a shovel, blanket, flares, etc. because it could be 50 to 100 miles to "civilization", on unmarked, dangerous roads. Some of that mentality carried over to riding the bike. I don't like feeling helpless.