The food guide pyramid was first introduced in 1916 with 5 food groups and has evolved over time based on new nutritional science. The 1992 USDA version depicted the optimal daily servings across grains, vegetables, fruits, dairy, and proteins with fats, oils, and sweets at the top in limited amounts. It was replaced by MyPyramid in 2005 to emphasize more individualized nutrition. The food pyramid provides guidelines for daily intake of major nutrients from each group and serves as a tool for maintaining a balanced diet and healthy lifestyle.