Sustainable food movement superstar Dan Imhoff will take part in a panel discussion of how living the foodie lifestyle has turned into a political act at Lit Crawl’s “Chew on This: A Fresh Take on Our Obsession with Food,” 3 p.m. Saturday in Berkeley. Like all Lit Crawl events, it’s free. Join the discussion at the Marsh Arts Center at 2121 Allston Way.