How much for the air? As much as half of food packaging is empty space

Food manufacturers, like the politicians currently debating health reform, may have a solution to the obesity crisis: Feed Americans a lot of hot air. But this heated air is not just a figure of speech for packaged goods companies including Ralcorp Holdings' (RAH) Post Foods and PepsiCo (PEP) subsidiaries Frito-Lay and Quaker.

In many packaged products, as much as 50% of the contents is just empty space, an investigation by Consumer Reports reveals. And we consumers are buying that nothingness every day.