It seems your eyes really can be bigger than your stomach.

A University of Illinois at Urbana-Champaign study found that visual clues can play an important role in food intake.

The study included 54 adults who were served free soup. Half of them ate from normal 18-ounce bowls. The other half ate from identical bowls that were slowly refilled through tubing connected to hidden soup cauldrons. The participants didn't know that as they ate, their bowls kept refilling with soup.

During the 20-minute lunch, the participants who ate out of the refilling bowls consumed 73 percent more soup and 113 more calories than those who ate out of the normal bowls. But the participants who ate of the bottomless bowls believed they consumed the same amount as the other participants and rated themselves as being no more full.

"People use their eyes to count calories and not their stomachs. This can be dangerous to our diets," study author Brian Wansink, a professor of marketing and nutritional science, said in a prepared statement.

The study appears in the current issue of Obesity Research.

Wansink said it's possible to use visual clues to our advantage when it comes to controlling the amount we eat. For example, he suggested repackaging snacks and other bulk foods into small plastic bags. Seeing these small bags filled with food can lead you to believe that a smaller-than-normal serving is a satisfying full serving.