But gluttony as sin makes sense, says professor Rodger Bufford, who teaches psychology at George Fox University, a Quaker institution in Oregon. Overeating can hurt our health and therefore, by extension, can hurt others, including our families and everybody else whose insurance rates go up because we over-indulged. And "at a deeper level," Bufford says, "I think it affects our relationship with God."

Whatever we focus on obsessively, he says, "in a sense is a false god for us. At some level or other we're saying, 'This is the most important thing in the world to me.' "

There are countless ways to live "out of proportion," Northway says: owning 60 pairs of shoes, sending text messages too often, running too much, taking showers that last too long, being the kind of person who never puts boundaries on what they ask of other people.

Like all of the seven deadlies, gluttony is not a stand-alone sin, and it's sometimes hard to tell where gluttony stops and greed or pride begins.

"The irony of gluttony," says Neale Donald Walsch, author of "Conversations with God," is that we imagine at first we are grabbing all the happiness we can grab in its many varied forms. But the truth is that we are pushing it away from us. Gluttony never results in long-term happiness."

Gluttony, Francine Prose notes in "Gluttony," part of the Seven Deadly Sins series published by Oxford University Press, is seen as a "gateway" sin. Start overeating and drinking too much alcohol and who knows what will happen next. Prose quotes Aquinas, the 13th century theologian, who listed six "daughters" of gluttony: "excessive and unseemly joy, loutishness, uncleanness, talkativeness, and an uncomprehending dullness of mind."

Gregory the Great, who came up with his famous list of the seven deadlies in the sixth century, outlined the ways a person could be gluttonous: too soon, too delicately, too expensively, too greedily, too much. If you spent too much time fussing over and preparing the food — what today we might call a gourmet — that was considered gluttony. If you thought too much about not eating — what today we call dieting or, at its extreme, anorexia — that was gluttony, too.

Americans, notes David Smith, professor of philosophy and religion at Central Michigan University, have a conflicted attitude toward gluttony. We can't get enough of trendy new restaurants and cooking channels, and we're bombarded daily with ads for bacon cheeseburgers and soda and beer. On the other hand, we're obsessed with losing weight and getting buff. We want both kinds of six-packs — and, either way, we're preoccupied.