Lessons Specifically for Pre-Kindergarten/Elementary School Kids:

1. Long list of lessons for elementary school kids from John C. Stalker Institute of Nutrition.
2. Fit Sanford offers various lessons, posters, games and other resources. A good example is this lesson on Why Food is Fuel, aimed at K-2.

Lessons Specifically for Middle/High School Students:

1. Drexel University put together great lesson plans for High School students
2. This curriculum connects health, farming and sustainability - contains discussion guides that go along with a video (must be purchased) that covers a variety of topics.
3. Long list of lesson for Middle school kids and for High school kids from John C. Stalker Institute of Nutrition
4. USDA's Team Nutrition program has put together project-based learning activities that meet educational standards for English and health for 6th graders. Fueling My Healthy Life takes students on a deeper dive into the importance of breakfast
5. The Edible Schoolyard project has examples of lessons that center around gardening!

A few more websites with resources for all ages, K-12 and adults

1. The following is a really interesting curriculum for Food Day on October 24th, but the information can be used year-round!
2. Lesson Plans/Activities for all ages!  Also divided by education topic (social studies, english) 

Great resource that links to other nutrition education material and lesson plans. Some of the material is in English and some is in Spanish!