An excerpt from Brian Wasnick, author of Mindless Eating:

In a recent study, researchers from my Cornell Food Lab asked 133 participants from Paris and 145 from Chicago to complete a brief survey on their food habits, posing the question “How do you know when you are through eating dinner?”

The Parisians said they knew they were through when they no longer felt hungry or when the food no longer tasted good to them. Their answers suggested that they’re influenced by internal cues — whether they liked the taste of the food or whether they wanted to leave room for a later dessert — to tell them dinner’s over. In Chicago, it was a different ball game. The 145 Americans relied on external cues of satiety. They said they knew they were through eating when they cleaned their plate, when everyone else at the table was finished or when the TV show they were watching was over.

The Americans were more influenced by their environment than whether they were actually still hungry. Since most of the signals in our society, from TV commercials to our best friends, tell us to “eat, eat, eat,” it can be difficult to control intake if we’re ignoring our own bodies.

The study, conducted by Collin Payne and Pierre Chandon and published recently in the journal Obesity, also found that, for both the American and French participants, the heaviest people tended to be the ones who relied on external cues to tell them when to stop eating.