Translation:Before, I ate in order to live. Now I live to eat.
Wouldn't using 'antaue + past participle' imply the imperfect tense? 'previously i ate' = ' I used to eat' so the 'before' in the translation is superfluous.
Por="for/because of/in order to" "I eat (in order) to live now i live (in order) to eat". In English the "in order to" can be left out but other languages require it for certain verbs. Also be aware that "for" in English indicates may things, purpose/use of/exchange/causation, in many other languages these are separate words e.g. Spanish Por=Exchange/Causation "here are some beans (in exchange) for your cow" Para=Purpose/Use of "here are some beans for your cow (to eat)" .
If you said "Mi manĝis vivi" that literally means "I ate living." When you see an infinitive in Esperanto, it's usually acting like a noun, or maybe a verb where the verb that precedes it is a helping verb or a linking verb.
Literally, "Mi manĝis por vivi" means "I ate for living." A word-for-word translation would be, "I ate for to live," but we don't use infinitives that way in English.
Now, a word-for-word translation of "Mi manĝis vivi" would be "I ate to live", but it doesn't mean what it first sounds like; it literally means you ate the infinitive "to live". In any translation, you can't just translate word for word; you need to know what part of speech each word is and how all the words go together.
Yes, "vivi" can translate as "to live", but in "I ate to live", the "to" is not that same indication of an infinitive. Rather, it's a preposition meaning something like "for the purpose of". Strictly speaking, the English would have to be "I ate to to live" to get the proper infinitive, but that second "to" is dropped. It's still present if the preposition in front of it isn't "to.": "I ate so as to live.", "I ate for to live.".
Esperanto doesn't drop a word here, hence it requires both the preposition and the infinitive. The infinitive is "vivi", the preposition is "por": "I ate for to live."