A "step above" the infamous "cast-iron stomach", this term refers to a digestive tract that's supposedly so "bulletproof" that the eater can consume virtually anything that's even "remotely edible", such as burned/fermented dishes, food that's gone so stale that "even da dog won't touch it", etc.
A local farmer-family was gonna just toss a whole heaping bushel-basket full of overripe vegetables that they didn't wanna try to sell, but I hastily begged them to let me have the produce, since I have a stainless-steel stomach, and so I really didn't mind stuffing my face on squishy cucumbers, woody-skinned hubbards, and semi-flabby zucchini for da next few weeks, since it saved me something in Food Stamps. A bit of an insipid-tasting chore, to be sure, but fortunately I happen to really like cukes and squash. so it worked out okay for me.
by QuacksO November 15, 2018