Brian Wansink, a professor of marketing and nutritional science at the University of Illinois at Urbana-Champaign, challenges the theory that eating habits and dieting can be chalked up to willpower or the lack thereof.
Wansink says little-understood contextual cues can lead people to overindulge and unknowingly eat more in an article recently published in the Journal of Consumer Research. These cues include appearance factors such as how food is displayed and variety of colors.
For example, adults offered six colored flavors of jellybeans mixed together in the same bowl ate 69 percent more than when the colors were each placed in separate bowls.
In another study, moviegoers given M&Ms in 10 colors ate 43 percent more than those offered the same number of M&Ms in seven colors.
Wansink and study co-author Barbara E. Kahn found that both variety and the perception of variety stimulate how much a person consumes.
"People eat with their eyes, and their eyes trick their stomachs," Wansink said in an interview. "If we think there's more variety in a candy dish or on a buffet table, we will eat more. The more colors we see, the more we eat."
In the case of jellybeans, a variety of flavors in a bowl drew comments such as "looks really colorful," "feels enjoyable," "satisfied as I ate" and "gives me at least one flavor that I like" from the study participants.
An earlier study by Wansink found that moviegoers given an extra-large bucket of popcorn will eat up to 50 percent more than those given a container one size smaller -- even when the popcorn is stale.
