USDA's food pyramid faces criticism.

With obesity reaching epidemic proportions in the U.S., some critics say the government's food pyramid needs a reassessment. The pyramid, dating from 1991, pictorially reflects USDA's guidelines on what Americans should eat every day to maintain a healthy weight. From a broad base of six to

While the government has stood by this regimen for 11 years, some critics say it's no coincidence that the number of overweight Americans has risen 61% since the pyramid was introduced -- and almost instantaneously appeared on the sides of pasta boxes, bread wrappers and packages of other food products in the pyramid's six-to-11-servings category.

David S. Ludwig, an obesity researcher at Children's Hospital in Boston, says the pyramid and guidelines focus too much on reducing fat. He says people are getting fat because they are eating too many refined carbohydrates, such as those in white bread, that make them feel hungrier later so they overeat. The habitual consumption of foods with refined carbohydrates "may increase risk for obesity, type 2 diabetes, and heart disease," he wrote in a May article in the Journal of the American Medical Association.

Steven Christensen, an official at the USDA's Center for Nutrition Policy and Promotion, says the pyramid represents guidelines for healthy eating -- not the next fad diet. "It wasn't meant as a way to reduce your weight, but if you eat this way, you're going to be all right."

The debate is particularly relevant in that the USDA currently is reviewing its dietary guidelines, as it does every five years. It's an exercise that attracts not only critics from the world of medicine but industry lobbyists and those promoting the virtues of various food groups and diets. During the last revision, the advisory committee considered changing the 1995 recommendation of adhering to a diet "moderate" in salt and sugar to "eating less salt and sugar." The powerful sugar industry fought the change, and the guidelines now tell consumers to "moderate your intake of sugars."

Unlike the guidelines, the pyramid isn't reviewed periodically. But the USDA decided recently to review the pyramid's serving sizes and try to make the depiction clearer for the guide's 10th anniversary. It will be years before all the complaints are weighed, but the USDA, at least for now, doesn't seem inclined to abandon the basic premise that a low-fat diet is healthiest. "You can't pinpoint the cause of obesity...to carbohydrates," says the USDA's Mr. Christensen.