A new "study" claims that over the past 1000 years the size of food portions depicted in "Last Supper" paintings has steadily grown. A computer analysis used 52 images from the 2000 coffee table book "Last Supper." The researchers compared the size of the plates and the food servings on those plates using the apostles' head sizes to calibrate the measurements. Let's hope none of the painters were going through a Caricature Art phase... I'm not being completely facetious here.
As the Got Medieval blog points out, there's plenty of proportional wonkiness in medieval art. Realism wasn't the goal back then. In fact, the size of objects usually conveyed their symbolic importance. Furniture and architecture weren't considered interesting enough, and hands were disproportionately large because they needed to show gestures in order to tell a story.
Anyway, I'm not even sure what we were supposed to conclude from this study, but plenty of reporters have used it as another opportunity to remind us how fat we are.