Feeds still work
Every word of this post was written by a person.
No algorithm decides who sees a feed. A reader subscribes, the site publishes, and that is the entire relationship.
Publish both
RSS 2.0 and Atom 1.0 are both a few hundred bytes of XML per post. Readers handle either, so publish both and let them choose. This site does: feed.xml and atom.xml.
Put the whole post in the feed
A feed that holds only the first paragraph trains readers to leave. Put the full text in; the reader who wants the page will click anyway.