What do you value in your food? Taste? Nutrition? Something that fills you up or reminds you of your past? Much of what America consumes is high in calories and low in nutrition, and according to the Centers for Disease Control & Prevention, childhood obesity has more than tripled in the past 30 years. Food historian ANDREW SMITH discusses the history of the fast-food restaurant, Arby’s to Doritos to TCBY, in his latest book, “Fast Food and Junk Food: An Encyclopedia of What We Love to Eat.” He’ll discuss what major fast-food restaurants respond quickly to negative health and labor reports, what he did to get some high-profile, multinational food companies to share their records after years of persistence, and how he offsets his love for chocolate and fried potatoes.