Here you can request a free package that includes, lesson plans, worksheets, a poster, game cd, music cd, and family tips.  All geared towards teaching the food pyramid to your children.  You can also download lesson plans.

http://teamnutrition.usda.gov/resources/mypyramidclassroom.html

http://www.mypyramid.gov/kids/index.html

This site offers six lessons with a math base.  There is a list of books, links to other sites, and a link to an online game all to help strengthen the teaching of the food pyramid.

http://illuminations.nctm.org/LessonDetail.aspx?ID=U48

This is a wonderful site everything you need to make learning about nutrition fun.

http://www.nutritionexplorations.org/educators/pyramid-main.asp

This site offers games to learn about nutrition.

http://exhibits.pacsci.org/nutrition/noflash_nutrition.html

Learn about your veggies with the help of these dinosaurs. 

http://www.leafy-greens.org/lessonplans.html

6 different lessons which include pretest, post test, and answer keys.

http://teachhealthk-12.uthscsa.edu/pa/pa07/07-youarewhatyoueat.htm#objectives

Have a blessed day!