With Americans packing on the pounds, nutrition experts have scorned the U.S. Department of Agriculture's food-guide pyramid. Studies show that people recognize the graphic but don't put into practice the dietary information. This week, the USDA tried to change all that with a new, interactive food pyramid for implementing the 2005 dietary guidelines, released in January. MyPyramid.com, USDA's new website, gives users the tools to map out a personal diet and exercise plan that incorporates the new guidelines, which promote eating more fruit, vegetables, whole grains, fish, and low-fat dairy products. And for the first time, the food guide emphasizes exercise—a figure runs up a flight of stairs alongside the pyramid.

The problem, say some nutrition advocates, is that MyPyramid doesn't indicate what not to eat—high-fat, sugary, high-calorie foods—though this caution is spelled out in the new guidelines. "People are going to have to walk up an awful lot of steps, hours of walking up steps, to take off what most Americans are eating," says Margo Wootan, nutrition policy director at the Center for Science in the Public Interest. "USDA dodged the politically difficult question of which foods we should eat less often. It's a missed opportunity."

Find out more: Read about the new food guidelines at USNews.com.

You can check out the new site and your own diet plan at www.mypyramid.com.