Pointing to the nation's growing obesity issues and related health problems, the federal government acknowledged that the traditional food pyramid, taught in classrooms across the country, has done little to curb Americans' appetites.

"It's become quite familiar," said Mike Johanns, U.S. Department of Agriculture (USDA) secretary, "but few Americans follow the recommendations."

He and other health officials hope a revised version of the pyramid will spark interest in healthier diets.

The new pyramid changes the horizontal levels of the old pyramid to vertical ones. The former pyramid included a base level of grains — showing the food that should make up the largest part of a person's diet — and a narrow top of sweets, fats and oils, with other foods in between. The new pyramid uses vertical bands of different widths to demonstrate these proportions.

The purpose for the change is to show that not all grains, for example, are the same. The wider bottom of each band represents foods that should make up larger portions of a diet, such as whole grains, while the point of each band represents those that should be limited. The new pyramid encourages eating lean meats and drinking low-fat milk, for example.

The new pyramid is based on a report called Dietary Guidelines for Americans, released in January. The guidelines, published every five years, are developed by an advisory committee appointed by the USDA and the U.S. Department of Health and Human Services.

"You've got to understand that nutrition is a moving target," said Janet Gilchrist, director of clinical nutrition research for the Arkansas Children's Nutrition Center in Little Rock and an employee of the USDA. "There are new studies that come out every day. We're finding out new things all the time about what is the healthiest thing."

While the pyramid's new look is the most striking change, there are substantive differences as well. Nutritionists uniformly applauded the government's inclusion of physical activity in the figuring of nutritional needs.

Physical activity is represented on the new pyramid with steps running up the side of the pyramid and a figure jogging up them.

The pyramid also provides food measurements in ounces and cups rather than in serving sizes that are unfamiliar to many people.

A USDA website — www.MyPyramid.gov — dedicated to the new symbol, is designed to allow users to obtain more personalized dietary recommendations. Users will be able to type in their age, sex and physical activity level and receive one of 12 versions of the pyramid that best fits them, including the number of needed calories and in what proportions.

The physical activity component and a more personalized approach addresses a misunderstanding that has long irked nutritionists. Not everyone needs the same amount of servings. The old pyramid, for example, indicated that six to 11 daily servings of grains were appropriate, but it failed to note that not everyone should be eating 11 servings.

In creating the new pyramid, the Agriculture Department said it wanted to provide better, more comprehensive nutritional information.

"It became clear that we needed to do a much better job of communicating the nutrition messages, so that Americans could understand how to begin making positive changes in their lifestyles," according to a transcript of remarks Johanns made in Washington.

However, the additional information led to some complaints that the new food pyramid is less user-friendly than the old version. Unlike the original pyramid, its meaning is not immediately understood, health officials say.

The new pyramid stirred less immediate complaints from the food industry than the 1992 version. The first version was withheld for a number of months after the meat industry criticized the relatively small proportion of meat it recommended. The final 1992 version recommended two to three daily servings of meat and dairy products.

For a 2,000-calorie diet, the new pyramid recommends 5.5 oz. of meat each day.

The American Meat Institute, which represents the nation's largest meatpackers, emphasized that "lean cuts of meat and poultry were again recognized as being key, healthful components of the daily diet by their inclusion in the USDA's newly published recommended dietary guidelines."

Commenting on the announcement of the revised Food Guide Pyramid, Cal Dooley, president and CEO of the Food Products Association (FPA), made the following remarks:

"FPA applauds Johanns and USDA for their commitment to furthering consumer education and nutritional awareness. The announcement by Johanns marks the next evolution of America's Food Guidance System into MyPyramid.

"MyPyramid and USDA's interactive website will allow consumers to personalize information related to their food choices, coupled with their level of physical activity. While the pyramid has evolved — the need for additional consumer education on health and nutrition remains strong. The nutrition labels on food products play an important role in helping consumers to choose foods appropriate for their dietary needs.

"Consumers need to understand how to put dietary guidance messages, such as those contained in MyPyramid, into daily practice. For example, most consumers should increase their intake of fruits and vegetables. Consumers need to know that canned, frozen and dried fruits and vegetables, as well as fruit juices and juice-containing beverages, can play an important role in ensuring adequate fruit and vegetable intake. The same applies to consumers availing themselves of the wide variety of whole grain options available, as they move to include more whole grain products in their diets. It is important that the emphasis remains on positive dietary choices, to ensure good nutrition and adequate hydration.

"The integration of a reference to physical activity in MyPyramid is an important addition. Because of the inseparable link between physical activity and food intake for energy balance, weight management or weight loss, including physical activity as part of a healthful lifestyle will increase the effectiveness of MyPyramid.

"FPA and its member companies are committed to helping consumers understand how to use the nutrition labels on food products — in concert with MyPyramid and the 2005 Dietary Guidelines for Americans — to help make food choices that will create healthful diets and lifestyles."