It took four years and a whopping $2.4 million, but the U.S. Department of Agriculture has finally rolled out a redesigned version of the Food Guide Pyramid. Unveiled a week ago, the new “MyPyramid” is supposed to offer Americans clear guidance on how to eat a nutritious diet and maintain a healthy weight.

But somewhere, somehow, this ambitious renovation project went terribly wrong. As a nutritionist, I think the result is an unsightly graphic that seems almost deliberately calculated to confuse and mislead consumers struggling with obesity, diabetes and other diet-related illnesses.

The old pyramid, which was created in 1992, had flaws, and many consumers simply did not follow its advice. But it did offer one clear message: Eat more foods (such as vegetables and grains) from the wide spaces lower on the pyramid and fewer sweets and other foods from the narrow spaces near the top.

The new version, however, is a puzzling mess. The pyramid has been flipped over on its side. A prism of six colors now shoots through the inside, and a stick figure runs up a set of stairs to the top. In its simplest form, the new graphic does not feature any food icons for easy recognition. Instead, it offers color-coded wedges without pictures or labels.

Designed for the USDA by Porter Novelli International, a PR firm that has also worked for McDonald’s and the Snack Food Assn., the new pyramid sports the slogan “Steps to a healthier you.” But the new design actually represents a giant step backward on several important nutrition issues.

First, it’s clearly intended to convince consumers that there are no bad foods. That message may please Porter Novelli’s food-industry clients, but it’s not consistent with the scientific evidence. All foods are not created equal when it comes to promoting health and preventing disease.

We’ve known for decades that saturated fat and cholesterol are key risk factors for cardiovascular disease, the nation’s leading cause of death. Unfortunately, the new chart itself offers no warnings about these food constituents or the foods that contain them, though mild cautions can be found in the fine print below the larger version.

It’s particularly disturbing that the milk group cuts such a broad swath through the new design. The USDA is now recommending three servings of dairy a day, even though fluid milk is already the largest source of saturated fat in children’s diets, according to the National Institute of Child Health and Development.

The full-blown version of MyPyramid even features images of high-fat cheddar cheese. Not pictured are more healthful sources of calcium, including some soy foods. The 50 million Americans who are lactose intolerant will find this focus on dairy products particularly hard to stomach.

Second, MyPyramid doesn’t offer a clear guide to healthy weight loss. From the National Weight Control Registry to the China Health Study, research suggests that people who maintain a healthy weight over the long run tend to eat a low-fat, plant-based diet rich in fruits, vegetables and whole grains. Such habits also reduce the risk of heart disease, diabetes and cancer.

But MyPyramid offers no clear advice about choosing low-fat foods from plant sources. Instead, it seems to suggest that Americans can regularly eat high-fat fried chicken or lunch meat as long we climb some stairs now and then. That’s not a solution to our nation’s weight problem; it’s a recipe for expanding it.

Somewhat better advice — including tips on vegetarian diets — can be found on www.MyPyramid.gov, the new USDA Web site that lets visitors enter personal information to create a pyramid to suit their particular age and habits.

But such online resources don’t meet the needs of consumers who do not or cannot use the Internet. What the country really needed was a simple graphic conveying a clear message about how to improve our eating habits.

By that measure, MyPyramid may be the most unsuccessful government construction project ever.

Tim Radak is nutrition director of the Physicians Committee for Responsible Medicine, 5100 Wisconsin Ave. NW, Washington, DC 20016, www.pcrm.org.