I had all my food in my base (built on the large flat rock by the garden posts), both in chests and sitting out on the spits.  I came back to my base to find a horde of ants underneath my base and all of my food gone.  I tested it a bit and it seems like they can just steal food from just about anywhere and any height as long as they can get below it.

I have a base on the baseball. On it’s 3rd floor, I have drying racks. Ants on the ground, around the baseball, can somehow eat the food on them. That’s crazy.