The food is specifically something called "gut berries". Each one makes you gain one kilogram. The only way to get out, is to get so fat that you're immobile. Then, the ropes will snap under your girth. The crates are marked with "gut-berries" written in chalk, but nothing else. Gut berries look like purple apples, but the size of a grape. Neither you, or Aubrey know what gut berries are.