I talk a lot about it because it's a subject I enjoy, and I'm a talker- anything I love, I like to discuss and share. However, I also 'walk it' and cook a lot. Since I started doing it for a living more, I do it less at home, but what I talk about is connected to what I learned by doing myself. I'm a "learn by doing" kind of person, and I make the knowledge my own best by trying it out. So I suppose I'm a little of both- but with all the cooking I do each week, be it for myself or my job, I believe I qualify as a foody geek rather than nerd.
Hmmm, by the definition Selkie posted, specifically when it comes to cooking and food, I'm probably somewhere in between but lean toward the geek side. By the venn diagram, I'm a geek with distinct dweeb, dork and nerd moments.