"Unit" food People tend to perceive pre-portioned units of food, such as a sandwich, burrito or pot pie, as something they'll finish, regardless of size.

"Blob" food Virtually everyone has trouble estimating portion sizes, and "amorphous" foods like casseroles are even more difficult to judge.

Stockpiling You're quicker to eat stockpiled food that's prominent in your mind. For example, you recently purchased it or it's perishable, a great bargain, heavily advertised or kept in an obvious place.

Seductive food names People eat more if a food has an enticing, creative description rather than a generic name.

Why you always have room for dessert

Brain-imaging studies conducted at University College London found that the "emotional" parts of people's brains scarcely lit up in response to a cue (an abstract picture) for a food they had eaten. But when people were shown a picture associated with a food they had not yet tasted, that same part of their brain fired right up.

"Once we have our fill of one food, the [cues] for it no longer motivate us to consume it," says neuroscientist Jay Gottfried, M.D., Ph.D. "But we are still motivated by other types of food."