Brian Wansink, Koert van Ittersum and Collin Payne, all of Cornell University in Ithaca, N.Y., served 69 preschoolers sugary cereal in either 8-ounce bowls or 16-oz bowls. Adults poured the sweetened cereal and milk in small increments, continually asking "Is that enough or do you want more?" until the kids indicated they were satisfied with the amount served.
No consumption was allowed in this study, Wansink said.
Results showed that when using the bigger bowl, kids requested 87 percent more cereal -- regardless of their age, gender or body mass index.
The researchers conducted a second study of 18 kids, ages 6-10, at summer camp. As in the first study, adults served the children cereal and milk in increments until they indicated they had enough food. But this time, the researchers used secret scales embedded within the tables to weigh each cereal portion before and after the kids ate to measure exactly how much they consumed.
The children requested 69 percent more cereal and milk when using large bowls and also ate 52 percent more, the study said.
In addition to taking and eating more, kids with large bowls also wasted about 14 percent more food than those with small bowls. More than 3-of-10 children reported using the same large-size bowl as their parents did at home, which might be causing them to over-serve and overeat, Wansink said.
The findings are scheduled to be published in the Journal of Pediatrics.