Using a pyramid shape to show what foods you should eat began when the U. S. Department of Agriculture (USDA) created the Food Guide Pyramid in 1992. Since then several pyramids have been added to the gallery to reflect the eating habits of different ethnicities (Latin and Asian) and points of view about what makes a diet healthy (the Mediterranean diet).

The U.S. Department of Agriculture revised the original pyramid and made it interactive. They called it MyPyramid. While it was full of great nutritional information, the USDA realized it was too complicated. The latest interactive nutrition guide has a new shape. It's called ChooseMyPlate.

Developed by Oldways Preservation & Exchange Trust and the Harvard School of Public Health, the Mediterranean Diet Pyramid was created after researchers noticed that people who live in the Mediterranean area (Italy, Greece, Spain) had lower rates of obesity, heart disease and cancer than do most Americans. (Researchers caution that diet is only part of the story, that Mediterranean people eat less than the typical American and get more daily activity.)

The typical Mediterranean diet, compared to an American one, is lower in saturated fat (animal fats from meat, whole milk and cheese); higher in monounsaturated fat (from olive oil); and places greater emphasis on vegetables, fruits and legumes.

Highlights of the Mediterranean pyramid:

• Specific portions are not given. Instead, foods are to be eaten "daily," "a few times per week" or "a few times per month."

• The foundation layer includes potatoes, polenta, couscous, bulgur and other grains. (The USDA lists only "bread, cereal, rice and pasta.")

• Beans, legumes and nuts have a greater prominence, reflecting their status as a basic dietary staple.

• Olive oil is emphasized by having its own layer in the middle of the pyramid.

• Fish, poultry, eggs and sweets are to be eaten just a few times per week.

• Red meat, at the top of the pyramid, is to be eaten just a few times per month.

• Wine is recommended, in moderation.