The size of food portions and plates in more than four dozen depictions of the Last Supper -- painted over the past 1,000 years -- have gradually gotten bigger and bigger, according to a Cornell study published in The International Journal of Obesity (April, online March 23), a peer-reviewed publication.

The finding suggests that the phenomenon of serving bigger portions on bigger plates -- which pushes people to overeat -- has occurred gradually over the millennium, says Brian Wansink, the John S. Dyson Professor of Marketing and of Applied Economics and director of the Cornell Food and Brand Lab.

"We took the 52 most famous paintings of the Last Supper and analyzed the size of the entrées, bread and plates, relative to the size of Christ's head," said Wansink.

The study found that the size of the entrées in paintings of the Last Supper, which according to the New Testament occurred during a Passover evening, has progressively grown 69 percent; plate size has increased 66 percent and bread size by about 23 percent, over the past millennium.

The research was conducted with Wansink's brother, Craig Wansink, professor of religious studies at Virginia Wesleyan College, Norfolk, Va., and an ordained Presbyterian minister.

Computer-aided design technology allowed images in the paintings to be scanned, rotated and calculated regardless of their orientation in the painting. The researchers started with the assumption that the average width of the bread is twice the width of the average disciple's head.

"The last thousand years have witnessed dramatic increases in the production, availability, safety, abundance and affordability of food," said Cornell's Wansink, author of "Mindless Eating: Why We Eat More Than We Think." "We think that as art imitates life, these changes have been reflected in paintings of history's most famous dinner."