July 10, 2012— -- If you're looking to cut calories, you might start by cutting your food into smaller pieces. So suggests a study reported Tuesday in Zurich, Switzerland, at the international conference for the Society for the Study of Ingestive Behavior.
Arizona State University researchers gave 301 hungry college students either a whole bagel or the same bagel cut into four separate pieces. Twenty minutes later, both groups of students were treated to a free lunch.
What the researchers found was that the college students in both groups ended up eating roughly the same amount of each bagel; however the students that ate the bagel cut in four pieces ate roughly 25 percent less of their free lunch than the students who ate the uncut bagel.
The phenomenon appeared to hold true in animals as well. As part of the same study, the researchers also found that when hungry rats were given a choice to look for food either as a single large pellet or 30 small pellets, the rats ran faster and more frequently to the small pellets.
"Cutting up energy-dense meal foods into smaller pieces may be beneficial to dieters who wish to make their meal more satiating while also maintaining portion control," lead study author Devina Wadhera said in a news release.
Wadhera and her colleagues are not the first researchers to examine the link between the way food is presented and how much of it we actually choose to eat. In 2005, Prof. Brian Wansink of Cornell University and colleagues devised an experiment in which subjects ate from soup bowls that, unbeknownst to them, continually refilled as they ate. These participants consumed 73 percent more soup than their counterparts eating from regular bowls -- even though they did not realize they had done so.
In another study in 2004, Barbara Rolls of the University of Pennsylvania found that increasing the size of a sandwich actually caused subjects to eat more calories, regardless of their hunger or satiety.
With regard to the current study, Keith Ayoob, associate clinical professor of pediatrics at the Albert Einstein College of Medicine, said that it's likely that eating four separate pieces might trick you into thinking that you are having four separate portions, whereas one whole piece is thought of as a single portion.
He said that this is similar to other ways our brains can influence our eating. For example, we take larger sips and drink more when a beverage is served in a larger container and eat more when food is served on a larger plate.
"Sometimes being 'full' is a mind game," Ayoob said. "It's not always just what's in your stomach."