Eating was the act of ingesting food. The food was usually taken through the mouth, being chewed with teeth before being swallowed. (WC: Teeth and Eating)
A mermaid-like race on Gorgol XIII were able to suck their food through their nostrils, albeit with great discomfort. (TV: Liberation)
The Fifth Doctor asked the Cyber-Leader when it last had the pleasure of eating a well-prepared meal. The Cyber-Leader, however, deemed this irrelevant. (TV: Earthshock)
The Daleks did not eat in the conventional sense, being fed by an internal feeding tube that harvested protein from the organic remains of victims. (TV: Into the Dalek) As a result of the Galtraxian DNA in its makeup, the Overseer conventionally chewed its food, its Ogron servants opening its casing and pouring the sustenance in. (AUDIO: Planet of the Ogrons)
In early 2005, following the Dummy Massacre, Nigel Dawson responded to Doctor Who?'s request for sightings of the then missing Rose Tyler, reporting having seen her the previous day outside Wetherby Whaler, eating something out of a newspaper and walking towards the bridge. (PROSE: The Doctor Was Involved in the Dummy Massacre)