For food ideas, and nutrition related activities you can get free publications through the USDA.
http://www.mypyramid.gov/
Go to online ordering, then check the childcare box and it will take you to an order form. There are lots of resources there, and they are all free. The Two Bites Club, near he bottom of the order form is an awesome free book (you can order 6) to share with the children and they get certificates and stuff at the end, if you want to do the activities. Read the list closely, there are many good items, and they are all free, including shipping.