from nbcnews.com: Why are Americans so fat? A new study suggests we've been getting it all wrong. It's not that we don't exercise enough or spend too much time at the office, or that good, healthy food is too expensive, researchers reported Thursday. And it's not about socioeconomic status, race or geography. Rather, the main reason we're getting fatter — all of us — is because we are surrounded by tasty temptations that cost very little, from fast food menus to processed snack foods, said the study's lead author, Roland Sturm, a senior economist at the RAND Corporation and a professor of policy analysis at the Pardee RAND Graduate School.