ingestion vs eating

ingestion and eating both are nouns.

Word	Noun	Adjective	Verb	Adverb
ingestion	Yes	No	No	No
eating	Yes	No	No	No

As nouns, eating is a hyponym of ingestion; that is, eating is a word with a more specific, narrower meaning than ingestion:

ingestion: the process of taking food into the body through the mouth (as by eating)
eating: the act of consuming food

Other hyponyms of ingestion include feeding, deglutition, drink, swallow, suck, sucking, suction, drinking, imbibing, imbibition.

ingestion (noun)	eating (noun)
the process of taking food into the body through the mouth (as by eating)	the act of consuming food