"Rather than eat candies, why don't you eat a plate of pasta?"
Translation:Piuttosto che mangiare caramelle, perché non mangi un piatto di pasta?
I believe that, as in English, when comparing two actions, you say the first one in "infinitive", because is kinda like an hypothetical scenario, and the second one is conjugated in the 2nd person, because is a recommendation to that person... So "rather than eating" becomes "piuttosto che mangiare" (both in infinitive form) and "why don't YOU eat a plate of" becomes "perché non MANGI un piatto di" (both conjugated in second person)... It also works that way in Spanish