The bad news in the report was delivered with an unmistakable "this will curl your hair" delight. Invoking the deadly Big Mac measure of comparison, it announced that a large unbuttered popcorn had the saturated fat equivalent of six Big Macs. With butter, that's eight Big Macs. The report did not say what happens to moviegoers who like to eat Big Macs along with their buttered popcorn.

Lest readers think that relief can be found elsewhere at the concession stand, the center also published charts of the fat and sugar content of the most popular candies. The findings are grim: 34 grams of "sat fat" in a box of Goobers, which is even worse than the 29 grams in a small buttered popcorn popped in coconut oil. The recommended daily maximum of saturated fat is 20 grams.

The methodology for the popcorn part of the survey was simple. The center bought popcorn at 12 theaters representing six chains in San Francisco, Chicago and Washington and then sent the samples to a laboratory. Then it compiled a chart showing the grams of fat in the sizes generally sold in movie theaters, setting up categories for popcorn popped in canola shortening (bad, but not as bad as coconut), coconut oil (very bad) and coconut oil with butter topping (buy a burial plot now).

At the Popcorn Institute, a trade group that represents popcorn suppliers, they're putting on a brave face. "We don't think people are going to run screaming from the building because popcorn is sold," said Deirdre T. Flynn, a spokeswoman for the institute. "If you eat it as a little indulgence now and then, it's not going to kill you."

Ms. Flynn has a point. The average American sees five movies a year. Even if a medium popcorn is a fat festival in a box, is it reckless endangerment to indulge five times a year? "It all adds up," said Jayne Hurley, who wrote the report. "A small unbuttered popcorn is an entire day's worth of artery-clogging fat."