As a verb, to preserve food is to process it to extend its useful life. To conserve food is to use it responsibly now so that enough remains later. As a noun, preserve refers to a food whose primary ingredients are fruit pulp and sugar, cooked to a thick consistency. ... Conserve can be a synonym of preserve.17 Nov 2012

Preserve ..... To keep doing/ being sth Conserve ... To keep sth That's what I understand