When I was younger and took chinese lessons, there was a push to use more "official" chinese. We'd be told that in official use "吃" is a verb used by ghosts (which is to say, it's impolite to use 吃, and "食" was to be used by humans. So... eh YMMV.
I personally find that elitist though, but then again, in chinese history there was always a distinction between what the commoner spoke (白话文) and what the intellectual elites wrote (文言文) so I'm not surprised that this mentality has continued on
EDIT:
I'd also like to add that 食物 is food, which translates literally to "eat" and "thing". Put together it means "edible thing", i.e. food. The original meaning of 食 still means, "eat", not "food". It's a modern contraction that "食" means food
I had to look a bit to figure out how you got "qi" from a word pronounced "chi". 契, the right part of the character is pronounced qi4, as is the character 氣, which does have spiritual meanings. 契, however, has no such meaning (according to wiktionary), so I assume this is another one of those Chinese superstitious puns.
Is a preference for 食 a Taiwanese thing? All the mainland Chinese people I've ever heard say 吃.
There was a linguistic shift to prefer 吃. I would say it probably happened in the Cultural Revolution. In Cantonese 食 is pronounced "sek", and is regularly used - "sek fan" as in "eat rice".
Since HK was quite insulated from the Cultural Revolution, and evidence from older texts that use 食 all the time (喫 was not really used IINM), it would not be amiss to say that the development to prefer 吃 is quite new. Hence in my other post I mentioned that it was political agenda that drove selection of preferred words to use.
addendum: I think there is also a nice narrative in the shift to use 吃 - it was more a "commoner" word, and communism was then about replacing the elite sounding words with simpler words that is common to everyone.
乞 is most commonly used with 乞丐 (begger), but the etymology of the word comes from qi (气) according to zhongwen.com
I'm just suggesting from modern Chinese's perspective, because, after all, we are modern people. 文言文 (uh I don't know its English translation) is fun to read and learn, but it's like Latin since basically nobody writes it anymore.
I personally find that elitist though, but then again, in chinese history there was always a distinction between what the commoner spoke (白话文) and what the intellectual elites wrote (文言文) so I'm not surprised that this mentality has continued on
EDIT:
I'd also like to add that 食物 is food, which translates literally to "eat" and "thing". Put together it means "edible thing", i.e. food. The original meaning of 食 still means, "eat", not "food". It's a modern contraction that "食" means food