Fast food is already a lot like pollution — it's bad for you, but it's more convenient than the alternative, so it's really really hard to get rid of. Also it shows up frequently on the sides of highways. Now, environmental nonprofit Clean Water Action has found that, at least in the San Francisco Bay area, these two dirty birds flock together. More than half of the litter in the four cities the group studied came from convenience foods at McDonald's, Burger King, Wendy's, Starbucks, and 7-11.

Some of these places are at least trying to cut down on their trash quotient. Starbucks encourages people to bring their own cups, though less out of concern for the environment than out of rational self-interest (the company calculated it could save $1 million a year if people brought in reusable mugs). But others don't allow customers to avoid the takeout boxes and plastic cups — even though Clean Water Action estimated that it would have collected 31 percent less trash if people used renewable plates and utensils.