I wouldn’t be surprised if it’s as much a decision as it is for many humans. There is some evidence that, for some actions, what we think of as choices may just be retroactive mental explanations for bodily urges which we are in the process of initiating before we get the conscious “idea” to do so.

But individual tendencies and habits formed earlier in life are definitely contributors as well. Both my cats free feed and are lean, but both were raised on scheduled individual feedings for years before I adopted them.