... and if "fressen" is used for a person, it is to express that someone's eating like an animal, or just eating an absurd lot. Similar to "saufen", which is trinken for animals, or that's the original meaning.

"Sauf- und Fressurlaub" -> a kind of holiday that is all about putting stuff into you. Somewhat strong language.

This has been a topic in the Answers section several times already:

– February 2016: https://www.italki.com/question/344771

– January 2016: https://www.italki.com/question/341989

– October 2015: https://www.italki.com/question/327711

– July 2013: https://www.italki.com/question/205275