Text Box Tool: Why Does Pasted-In Plain Type Get Set in the Wrong Font?

For the Text Box Tool, I have the default font set in a certain face, size, and color. Every time I draw a new text box, whatever I type shows up in that font, size, and color. Yay!

However, when I copy text from a plain-text file and paste it into a new text box, the result is never, ever in my default font. Boo.

I'm running Acrobat XI v11.0.0 on a Mac (OS X v10.9.5). What do I need to do to ensure that any plain text (text stripped of formatting) pasted into a new text box gets set in my preferred font (and not, like, 13-pt. Lucida Grande)?

I'd greatly appreciate any help on this. Thank you so much!