“Fed Up,” which narrator Katie Couric pitched to producer Laurie David as an “Inconvenient Truth” for food, premiered for an activist audience that included chef Jody Adams at the Harvard School of Public Health this week. David, the ex-wife of comedian Larry David and an Academy Award winner for the 2006 Al Gore climate-change epic, dashed in after the screening for a few comments. She actually expressed optimism about the nation’s myriad food-related ills because of “the fact that there’s this terrible problem and the solution is in everyone’s kitchen.” Several times, David begged the assembled to “tell at least five people” about the film on social media, winning a promise of a Facebook “like” from 14-year-old Isaac Rimm, son of Eric Rimm, one of the other panelists whom moderator Louisa Kasdon introduced as “king of the school of public health.” (In fact, he’s an associate professor of epidemiology and nutrition at the Harvard School of Public Health.) “Fed Up” is just one of Laurie David’s current ventures. She also just published a cookbook, “The Family Cooks: 100+ Recipes to Get Your Family Craving Food That’s Simple, Tasty, and Incredibly Good for You.” It came out this week.