Researchers showed pictures of different foods to healthy participants. They had to predict the caloric content of each food and bid what they'd pay for their favorite food. During bidding, researchers scanned the area of participant's brains that helps evaluate food value. Both brain activity and bid amounts were highest for high-calorie foods. Participants were poor calorie estimators, so researchers believe the brain's preferences are built implicitly through experience of what fills us up efficiently.
PositiveTip: Train your brain to prefer tasty, but lower-energy foods.