http://www.mypyramid.gov/

Each of the different wedges in the pyramid represents a different food group. The variety of wedges symbolizes the variety of foods that we need to form a balanced diet.

The larger wedge, the larger the recommend number of servings from that food group.

The broad base and narrow top of each wedge symbolize that we should choose portion sizes that vary according to our calorie needs.

The shape also suggests we should eat a big base of nutrient-dense foods and taper off our intake of processed foods with less nutritional value.

The stairs symbolizes the message of taking small steps to a healthier lifestyle.

The person running up the stairs symbolizes the importance of daily exercise.
(Sports Nutrition Guidebook by Nancy Clark, MS, RD)