Pear

Pears were a type of fruit.

Pears were served at King Gilgamesh's court in Uruk. (PROSE: Timewyrm: Genesys)

When the Seventh Doctor turned himself into John Smith, he left instructions for Bernice Summerfield, one of which was to not let him eat pears, as he didn't like them and didn't want to wake up tasting that. (PROSE: Human Nature)

After the Tenth Doctor turned himself into John Smith, he ate a pear as he wandered near his fob watch. (TV: Human Nature)

The Twelfth Doctor also warned Clara not to eat pears as they were too "squishy", just before he lost his memories of her. He stated that it was extremely important, and told her to write it down. (TV: Hell Bent)

Behind the scenes
In a deleted scene from Human Nature, when the Tenth Doctor turned himself into John Smith, he left instructions for Martha Jones, one of which was to not let him eat pears, as he didn't like them and didn't want to wake up tasting that.