In his new book, Brian Wansink, a food psychology professor at Cornell University, explains why we eat with our eyes and not with our stomach, and how this can affect our weight.
The following is an excerpt from "Mindless Eating."
Did you ever eat the last piece of crusty, dried-out chocolate cake even though it tasted like chocolate-scented cardboard? Ever finish eating a bag of French fries even though they were cold, limp, and soggy? It hurts to answer questions like these.
Why do we overeat food that doesn't even taste good?
We overeat because there are signals and cues around us that tell us to eat. It's simply not in our nature to pause after every bite and contemplate whether we're full. As we eat, we unknowingly -- mindlessly -- look for signals or cues that we've had enough. For instance, if there's nothing remaining on the table, that's a cue that it's time to stop. If everyone else has left the table, turned off the lights, and we're sitting alone in the dark, that's another cue. For many of us, as long as there are still a few milk-soaked Fruit Loops left in the bottom of the cereal bowl, there is still work to be done. It doesn't matter if we're full, and it doesn't matter if we don't even really like Fruit Loops. We eat as if it is our mission to finish them.
Take movie popcorn, for instance. There is no "right" amount of popcorn to eat during a movie. There are no rules of thumb or FDA guidelines. People eat however much they want depending on how hungry they are and how good it tastes. At least that's what they say.
My graduate students and I think different. We think that the cues around us -- like the size of a popcorn bucket -- can provide subtle but powerful suggestions about how much one should eat. These cues can short-circuit a person's hunger and taste signals, leading them to eat even if they're not hungry and even if the food doesn't taste very good.
If you were living in Chicago a few years back, you might have been our guest at a suburban theater matinee. If you lined up to see the 1:05 p.m. Saturday showing of Mel Gibson's new action movie, Payback, you would have had a surprise waiting for you: a free bucket of popcorn.
Every person who bought a ticket -- even though many of them had just eaten lunch -- was given a soft drink and either a medium-size bucket of popcorn or a large-size, bigger-than-your-head bucket. They were told that the popcorn and soft drinks were free and that we hoped they would be willing to answer a few concession stand–related questions after the movie.
There was only one catch. This wasn't fresh popcorn. Unknown to the moviegoers and even to my graduate students, this popcorn had been popped five days earlier and stored in sterile conditions until it was stale enough to squeak when it was eaten.