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Why Visual Cues of Portion Size May Influence Intake

Wansink, B., Painter, J.E., & North, J. (2006). Bottomless bowls: Why visual cues of portion size may influence intake. Obesity Research, 13(1), 93-100.

A study conducted in an ice cream social setting gives a visual demonstration of how bigger bowls can drive up ice cream consumption.
Published: January 4, 2011

Do Americans tend to eat more than is necessary? The answer seems to be yes. Environmental cues have an impact on how much we eat, and we don't even know it. In a study conducted by professors Brian Wansink, James Painter, and Jill North, participants were seated at a table, four at a time, to eat soup. What the participants did not know is that two of the four bowls were attached to a tube underneath the table which slowly, and imperceptibly, refilled those bowls. Those eating from this "bottomless" bowl consumed an unbelievable 73% more than those eating from a normal bowl! They also estimated that they consumed 140.5 calories fewer than they actually did. This is a huge underestimate compared to the estimate of the group with normal bowls, who believed they consumed only 32.3 calories fewer than they actually did. Despite consuming significantly more soup and calories however, the group with the bottomless bowls did not feel any more sated than the group with the normal bowls. In fact, afterward, many of the participants admitted that they usually eat until they reach the bottom of the bowl, and often clean their plate when eating at home. So, next time you sit down for a meal, keep in mind that relying on visual cues like an empty bowl might actually lead you to overeat!

Brian Wansink demonstrates the 'bottomless bowl' concept after he was awarded a 2007 Ig Nobel Prize at Harvard University.

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Article Summary by Meghan Witherow
Full text paper: (available as a pdf by clicking here)

Brian Wansink, PhD
Food and Brand Lab, Director
110 Warren Hall
Cornell University
Ithaca, NY 14853