Religions do not regard gluttony (from the Latin word for “gulping down”) as a virtue. According to the list compiled by the great Middle Ages Jewish scholar and physician Maimonides (the Rambam), of the 613 commandments that Jews must observe, excessive eating or drinking is prohibited (and is listed as #169). Christianity too regards overindulgence at the dinner table as a transgression and even one of the Seven Deadly Sins.
The obesity epidemic in the Western World, including the U.S. and to a lesser extent Israel, shows that there are too many gluttons, and greedy eaters are suffering from chronic diseases from heart attacks and strokes to diabetes and kidney failure as a result.
It has long been suggested that if you serve food on smaller plates, those who eat from them will eat less. Even restaurants have adopted this idea, which was based on an illusion first described by Joseph Delboeuf, a 19th-century Belgian mathematician, psychologist and philosopher. It is an optical illusion of relative size perception. In the best-known version of this illusion, two circles of identical size are placed near to each other and one is surrounded by a ring-shaped object (annulus). The surrounded circle then appears larger than the non-surrounded circle if the annulus is close, while appearing smaller than the non-surrounded circle if the annulus is farther away.
But researchers at Ben-Gurion University of the Negev in Beersheba have concluded that “tricking” the brain into eating less by serving food on a smaller plate does not necessarily work. Writing in the latest edition of the medical journal Appetite, they found that when people are hungry, they are likely to assess the size of a food portion accurately – no matter how it is served.
Their work was the first study ever to examine the way food deprivation affects the perception of food in different contexts. “Plate size does not matter as much as we think it does,” said Dr. Tzvi Ganel, head of the laboratory for visual perception and action in the university’s psychology department. “Even if you are hungry and have not eaten or are trying to cut back on portions, a serving looks similar whether it fills a smaller plate or is surrounded by empty space on a larger one.”
Ganel and BGU doctoral student Noa Zitron-Emanuel found that people who had not eaten for at least three hours were more likely to identify the proportions of pizza placed on larger and smaller trays correctly than people who had eaten recently.
Interestingly, this worked only when it applied to food; both groups were similarly inaccurate when asked to compare the size of black circles and hubcaps placed within different sized circles. According to the researchers, this indicates that hunger stimulates stronger analytic processing that is not as easily fooled by the illusion.
“Over the last decade, restaurants and other food businesses have been using progressively smaller dishes to conform to the perceptual bias that it will reduce food consumption,” concludes Ganel. “This study debunks that notion. When people are hungry, especially when dieting, they are less likely to be fooled by the plate size, more likely to realize they are eating less and more prone to overeating later.”