When people use smaller dinnerware (plates, bowls, cutlery, etc.), they eat less...
Social psychologist Brian Wansink and marketing researcher Koert van Ittersum invited the colleagues of nutritionist James Painter to celebrate his success at an ice cream social. Eighty-five nutrition experts showed up. The researchers randomly assigned partygoers to receive either a smaller (17 oz.) or larger (34 oz.) bowl, and either a smaller (2 oz.) or larger (3 oz.) ice cream scooper. Participants then filled out a survey while researchers weighed how much ice cream participants put in their bowls. By the end of the party, all but three participants had finished their ice cream.
The researchers found that participants with larger bowls ate 30% more ice cream than did those with smaller bowls. Likewise, participants with larger serving spoons portioned and ate 14% more ice cream than those with smaller spoons, regardless of their bowl size. Altogether, people with both a larger bowl and a larger spoon ate 50% more ice cream than people with smaller bowl and spoon pairs.
In addition, the survey revealed that none of the participants—who were, after all, nutrition experts—were aware of the experiment as it happened. Indeed, participants with smaller bowls believed they had served themselves more ice cream than did those with bigger bowls.
Why This Works
People base their portion size on how it looks relative to their plate, bowl, cup, and utensils. And so the bigger the dinnerware, the bigger the portions. Additionally, most people “clean their plates,” mindlessly eating until no food is left, rather than until they are physically full. When people use smaller dinnerware, their portions are also smaller, so “cleaning your plate” actually results in eating less food than when people use larger dinnerware.
When This Works Best
Even nutrition experts, who should be aware of portion control and mindless eating, respond to this subtle intervention. Therefore, this intervention likely works for nearly anyone who wants to eat less.