1. ^*Applied Economics and Marketing, Cornell University, Ithaca, NY
2. ^†Family and Consumer Science, Eastern Illinois University, Charleston, IL
3. ^‡Food Science and Human Nutrition, University of Illinois, Champaign, Illinois

Correspondence: Brian Wansink, 110 Warren Hall, Cornell University, Ithaca, NY 14853-7801. E-mail: Wansink@uiuc.edu

^**The costs of publication of this article were defrayed, in part, by the payment of page charges. This article must, therefore, be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Received 22 December 2003; Accepted 29 October 2004.

Abstract

Objective: Using self-refilling soup bowls, this study examined whether visual cues related to portion size can influence intake volume without altering either estimated intake or satiation.

Research Methods and Procedures: Fifty-four participants (BMI, 17.3 to 36.0 kg/m²; 18 to 46 years of age) were recruited to participate in a study involving soup. The experiment was a between-subject design with two visibility levels: 1) an accurate visual cue of a food portion (normal bowl) vs. 2) a biased visual cue (self-refilling bowl). The soup apparatus was housed in a modified restaurant-style table in which two of four bowls slowly and imperceptibly refilled as their contents were consumed. Outcomes included intake volume, intake estimation, consumption monitoring, and satiety.

Results: Participants who were unknowingly eating from self-refilling bowls ate more soup [14.7 8.4 vs. 8.5 6.1 oz; F(1,52) = 8.99; p < 0.01] than those eating from normal soup bowls. However, despite consuming 73% more, they did not believe they had consumed more, nor did they perceive themselves as more sated than those eating from normal bowls. This was unaffected by BMI.

Discussion: These findings are consistent with the notion that the amount of food on a plate or bowl increases intake because it influences consumption norms and expectations and it lessens one's reliance on self-monitoring. It seems that people use their eyes to count calories and not their stomachs. The importance of having salient, accurate visual cues can play an important role in the prevention of unintentional overeating.