This model is a means for visualizing the place garbage has in our lives. We can also use this model to understand how changes in diet, the environment, and the social system feed [sic] into one another: past, present, and future.
The left side of the diagram refers to extrasomatic (outside the body) elements. The right side of the diagram refers to internal or analytical components.
The menu is all items from the environment that people in the community could consume. [Think of going to the produce and meat sections of the grocery store.]
The meal is the combination of some, not all, available items and their processing into food (processing such as cooking, salting, drying, etc.). The meal is the component which principally defines the others. [What is chosen for a meal is eaten by an individual. What isn't in the meal is thrown away (midden). What isn't eaten isn't used by the person's body (and frequently thrown away). What isn't metabolized is thrown away / flushed away from the person.] Different people in a culture may have different meals, made from the same menu of foodstuffs (baby food vs. wedding food or Christmas dinner or parenteral nutrition).
The midden is our garbage dump / sanitary landfill. Items which were gleaned from the environment — then transformed culturally, physically, and chemically — are returned to the environment.