J.,
It looks like several people have given you wonderful ideas!
As they stated, there are a couple of ways you could go with your lesson plan.
A parallel between a plant and how children grow. If you wanted to go this route, you could use the book, "I'm a Seed." It is a wonderful easy read for preschoolers. I am making a huge assumption that you are doing the huge 9-12 step lesson plan for Drury (been a while since I did one). You would be able to show in your lesson plan how you how you are using different modalities and how the lesson plan will apply to multiple intelligences.
As you describe you procedure, your anticipatory set could be a brief explanation on how a plant is similar to a person using a live plant.
For the lesson you would read the story to the children. Then for input the children could answer questions about why they need water and sun to grow like the plant does.
For the Independent practice they could plant seeds that they would nurture to plants.
Another lesson plan would be to do one on a book similar to "The Berrenstain Bears and too much Junk Food." The good thing about this book is that it related to children of this age. You would set the lesson plan up similar to the one above.
For the Independent Practice you could do an exercise like the one Holly H. below describes.
There are also several other wonderful books out there that could be adopted for such a lesson plan, as others have described: How the Body Works; Watch me Grow: Fun Ways to learn About Cells, Bones, Muscles, & Joints." If you are having a hard time coming up with the book and you have to have the physical book, I recommend checking with your local elementary school. Some of the schools are still working admin days so you might be able to talk to one of the teachers.
When I had to do my health lesson plans, I borrowed a health book from my local elementary school first grade. I also have a very extensive library. :-) For the food pyramid, I got one from the health department. But sometimes those are too elaborate for the grade level you are looking for. The one in the Berenstain Bear's book is very simple and geared for this grade level and could be easily duplicated.
Unless you are presenting the lesson plan in class you probably don't need the book or the actual pyramid (unless they are now requiring you to turn in the full lesson plan complete with all resources). Although it sure does make completing the lesson plan a whole lot easier.
If you are interested in either of the books I mentioned give me a hollar off line. I probably still have a food pyramid in my MANY boxes of lesson plans if you need me to look for it.
Good luck! I hope my suggestions, added with the others gives you more ideas. If you want to talk off line give me a hollar!
N.