Three clay cooking pots and a small ceramic oil lamp where discovered inside a cistern in the sewer that runs from the Pool of Siloam to the Temple Mound in Jerusalem. These items indicate that someone around the time of 70 AD was eating food while they and the food were hidden in the underground tunnels. These were likely used by Jews hiding food from other Jews during the Roman siege of Jerusalem (69-70 AD) or hiding from the Romans themselves.
(details here and here;
photos here and here.)

Josephus records that the Jews hid in the underground tunnels and sewers to eat their food during the Roman siege of Jerusalem in 70 AD
to hide their food sources and the fact that they were eating from the others to prevent being attacked. See Josephus's words here:

“As the famine grew worse, the frenzy of the partisans increased with it….For as nowhere was there corn to be seen, men broke into the houses and ransacked them. If they found some they maltreated the occupants for saying there was none; if they did not, they suspected them of having hidden it more carefully and tortured them.” 
“Many secretly exchanged their possessions for one measure of corn-wheat if they happened to be rich, barley if they were poor. They shut themselves up in the darkest corners of the their houses, where some through extreme hunger ate their grain as it was, others made bread, necessity and fear being their only guides. Nowhere was a table laid…” (Josephus The Jewish War)

A machicolation, typical of castles and fortifications fo the Middle Ages, where hot oil or rocks were dropped on the invading enemy below.

One of the features of medieval warfare was the machicolation—a porch in the wall with openings between the supports (corbels) where hot oil, boiling water or stones could be poured or dropped through the floor down onto the invading troops below. The use of animal fat and oil was very dangerous for the defenders to use because it could reach 400 degrees F. The oil would not be boiled since the smoking point of oil (the temperature at which the oil begins
to break down) is lower than its boiling point. This means it would start smoking before it started to boil. This would make it difficult to reach the boiling point since the smoke would be extremely irritating to the eyes and throats of those who were heating it as a defensive weapon.

Josephus records the use of this technique in the following account:

They (Romans) began already to get upon the wall. Then did Josephus take necessity for his counselor in this utmost distress, and gave orders to pour scalding oil upon those whose shields protected them ...they (Jews) brought being a great quantity also, and poured it on all sides upon the Romans, and they threw down their vessels as they were still hissing from the heat of the fire: this so burnt the Romans, that it dispersed that united band, who now tumbled down from the wall with horrid pains, for the oil did easily run down the whole body from head to foot, under their entire armor, and fed upon their flesh like flame itself.

-Josephus, The Great Roman-Jewish War, III.7.27-28

See photos of machicolations here and here.