Control -- on a platter

"I wasn't personally too impressed with the numbers [in the diabetes study]," says Susan Roberts, a senior scientist in the Human Nutrition Research Center at Tufts University in Boston. Besides, "the plate method only touches the stuff you eat at home. . . . I would say eating at home is the least of our problems. Many people cook very little these days."

Overall, diet and nutrition experts agree that portion-control devices can't hurt and might help.

"If people use plate size as a tool to guide portion sizes, it would probably be useful," says Barbara Rolls, professor of nutritional sciences at Pennsylvania State University in University Park. "Anything we can try to do to educate people about appropriate portions is good."

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Out of proportion

Portion-control plates are intended to do just what their name says: get portion sizes under control. Most experts agree that portions have run amok.

Starting in the 1970s, portions in all food categories except bread have been growing, according to a 2002 study conducted at New York University. That includes portions served in restaurants, packaged items sold in grocery stores and portion sizes in cookbook recipes.

Some examples: Twenty years ago, an average-sized bagel was 3 inches in diameter and had 140 calories, according to figures from the National Heart, Lung, and Blood Institute. Now it's 6 inches across and packs about 350 calories. Twenty years ago, a cheeseburger, order of fries and a soda had 630 calories, fewer than half as many calories as the same 1,450-calorie meal, on average, today, according to the institute.

"People know portions are big, but they have no idea how big, and how much bigger they are than what we should eat," says Lisa Young, adjunct professor of nutrition at New York University.

And while portion sizes have been expanding, people have been doing the same. From 1976 through 1980, health professionals interviewed and examined thousands of people for the National Health and Nutrition Examination Survey and found that 15% of adults ages 20 to 74 were obese. When the survey was conducted during the period 2003 to 2004, the figure had more than doubled to 33%.

No one thinks that extra-large portions are totally responsible for extra-large people. And just because portions are mountainous doesn't mean people have to treat them like Everest and eat them just because they're there.