Oyster

When most people think of aphrodisiacs, they think of oysters. And why not? The appearance alone of an oyster on the half-shell is enough to cause lustful thoughts for many. See the article on asparagus for a description of the Doctrine of Signatures, which also applies here. The old, old reputation of oysters for enhancing the libido is even more prevalent in the public mind than the shellfish's suggestive shapes.
Casanova made ingenious use of them, but that's a story for another time.
Oysters have several qualities useful (in the long run) for lovers: They are low in fat, but high in protiens, complex sugars and zinc. Zinc is a very important part of testosterone, the hormone that governs sex drive in both genders.