Research that Changed Research: Bottomless Soup Bowl

When do you stop eating? Most people would say that they’ll stop when they feel full. A classic experiment called the Bottomless Soup Bowl found that most people today are not very good at detecting when they feel full. Why is that? Well, people rely on different cues to help make certain judgments. With regards to food, people rely on visual cues of portion size to determine when they should stop eating. Ever heard of the phrase “Cleaning the plate?” As a result, people do not feel satiety until they see that their plate is cleared, even when food portion is increased. Wansink defined this behavior as mindless eating.

To test Wansink’s hypothesis that visual cues of portion size influence consumption, 54 participants (18 to 46 years of age) were recruited to either be in the re-refilling soup bowl condition or the control condition. The following passage is from the original article:

“Despite consuming 73% more, those participants eating from the self-refilling bowls did not believe themselves to have consumed any more soup than those in the control condition. Those eating from normal bowls believed they had eaten 32.3 calories fewer than they actually ate. In contrast, those eating from self-refilling bowls believed they had eaten 140.5 calories fewer than they actually ate.”

The size of food portion has been increasing for the past years (All-you-can-eat buffets, super-size McDonald combo meals, etc.), along with the country’s obesity rate. The Bottomless Soup Bowl experiment opened a link to how eating behaviors influence food intake and helped DiSH Lab further examine what small behavior changes can help people eat better and maintain a healthy weight.