One way to make nutrition fun is to use newspaper grocery ads. After you talk about the 4 food groups have the kids cut out their favorite foods from newspapers and magazines. Then let them write about their choices to show they understand each group's contents. They could also list things that are made from that product or other things made from the same basic contents.
The class could also just cut out the names of products they like and have them draw the pictures on light colored construction paper for placemats. You could give each food group to a small group of kids and have them hunt together for food items in that group. They can then glue their selections on bulletin board paper and label them. That lets them make a bulletin board and all you have to do is supply the paper.
One other activity is to give each child a piece of construction paper with a letter of the alphabet and let them find any food or drink items that start with that letter. All pictures they find are glued on the paper. These can then be put in ABC order and made into a book. You keep the book so you can remember the activity.
Take pictures of everything. It's much easier to remember because you have a visual.