It's good to explore other perspectives concerning thoughts being food and now... plants.
Billy Meir, who claims being a contactee of aliens also claims to have seen prehistoric plants that are part animal and part plant. The aliens explained to Billy that most plant life on earth were once the dominant species of "animals". They thrived and evolved so far that they all became more oneness, which is what they are today.
Here is a link to a brief video. One part of it (towards the end of video) explains little of this.
http://www.youtube.com/watch?v=IrhEghb-1sc