Link: http://www.theatlantic.com/issues/2002/12/rauch.htm
I'm conflicted. Sure, the tongue is firmly planted in the cheek with this article ( the author does remark that he weighs a mere 135 pound) BUT..
On the one hand a tax targetting obese people, effectively taxing them "by the pound", has its merits. Why shouldn't we implement a disincentive for people to continue abusing their bodies especially when the entire community has the pay the cost. We do it with smoking.
On the other hand, there are many many reasons for why people are overweight or at least not within the "normal" healthy weight range. It may be because they're body-builders or even more disadvantageously, because they have a genetic predisposition ( leptin deficiency ). If there are issues with food these may be associated with an underlying depression or anxiety. It could be said that obesity in a certain range of people is sign of some psychopathology. Whatever it is, to suggest that obesity is something that can just be taxed out of existence underestimates the complexity of the disorder and indicates a failure to take into account the underlying conditions that result in obesity.
So yeah, a good idea for those who aren't affected...