A woman goes to the airport to meet the older brother she hasn't seen in a few years. She's 40, he's 44. "Yo, don't recognize your own brother?" he greets her.She doesn't, at first. "I peered into the round face, its features stretched as if painted on a balloon." He's no longer her brother, Edison, but "the creature that had swallowed Edison." When she last saw him he'd weighed around 165. Now he's close to 400.Hence the title of Lionel Shriver's novel "Big Brother." Set in Iowa, it's about fat, food and American culture. I knew I was going to like it as soon as Shriver had her narrator, Pandora, observe, "I have spent less time thinking about my husband than thinking about lunch."