I only eat non meat fast food and I do my best to buy items with the least amount of packaging or least harmful packaging. I love smoothies but most places use styrofoam cups so I usually make smoothies at home, same with hot beverages. A bean burrito at Taco Bell is really the only fast food I eat. I usually have my own bottled (glass or aluminum) water with me.
I eat fast food MAYBE once each month or two on those days where we're running around town doing a million things, we're starving, and we happen to have the money... those three rarely combine.