Late antique and medieval Zoroastrianism had dietary restrictions or at least ideals. We see for example in the Zoroastrian Jamasp-Namag that Arabs are criticized for eating worms, snakes, and other wild beasts(cats, leopards, and the like) and a late interpolation to the Shah-namah refers to Arabs as eaters of lizards. The reason for this bears some elaboration because it is very visibly religious. The creatures mentioned as discouraged, and especially lizards, serpents, insects, and other crawling things, are xrafstars; that is noxious creatures that were created by Ahriman in opposition to the perfect cosmos of Ahura Mazda and which Zoroastrian clergy are enjoined to kill. So while this is a similar practice of dietary restriction, it differs from the other practices mentioned in that it 1) is not ascetic in intent and 2) has a more specific specific cosmological grounding than Jewish or Islamic restrictions. EDIT: See Touraj Daryaee, "Food, Purity, and Pollution: Zoroastrian Views on The Eating Habits of Others".

Judaism and Hinduism are pretty old; wouldn't those count as ancient?