Does Global Warming Cause Obesity?

According to the latest environmentalist theory (seen via BoingBoing:

The idea proposes that breathing in extra CO₂ makes blood more acidic, which in turn causes neurons that regulate appetite, sleep and metabolism to fire more frequently. As a result, we might be eating more, sleeping less and gaining more weight, partly as a result of the air we breathe.

On the other hand, I thought obesity might cause global warming. After all, if you're too fat to walk anywhere or fit behind the wheel of a compact car, then you just might have a higher carbon footprint.

In related news, the fact that people who live in in the western U.S. (where “the scenery's attractive and the air is radioactive”) have low cancer mortality rates can mean only one thing: Radioactivity makes people stop smoking.