One size doesn’t fit all in an overweight country, so the Bush administration has introduced a dozen Internet versions of its staid Food Guide Pyramid to help American consumers make better eating choices.The U.S. Agriculture Department on Tuesday redesigned its longtime symbol to direct consumers to an Internet site where they can choose among 12 pyramids that calculate daily diet needs based on age, activity and gender.The new symbol, MyPyramid, displays a figure climbing stairs to emphasize the need for daily exercise.The USDA kept the basic shape of its controversial food pyramid, which was developed in 1992 and is readily recognized by most Americans from breakfast cereal boxes, lunchroom posters, and nutrition articles.