When you are shopping for food, use the way grocery stores are laid out to your advantage. Most stores put the healthiest foods—fruits and vegetables, meat, fish and dairy—around the outer ring of the store. These healthiest foods are also the ones that rot or go bad the quickest. "Food should be alive, and therefore it should die," Michael says.

Processed food—which is less healthy for both humans and the environment—is put in the aisles in the middle of the store. "That's where the stuff that never goes bad lurks," Michael says. "That's the processed food that really gets you into trouble. That has the most waste and takes the most fossil fuel to produce."