That’s the first I’ve heard of personal obesity as an externality. Frightening idea. What if someone lives a lifestyle that makes them more likely to contract an STD, say?
Regardless, STDs aren't a byproduct of some Fortune 500 company's quest to grow shareholder value. Obesity is.
None of the bathhouses ("while the band played on") were Fortune 500, but they were profiting.
It's fair to suggest that the behavior would have happened without bathhouses, but that same argument applies to McDs.
Note that the nutritonal information that McDs passes out has been more effective than the bowls of condoms were.
No, I'm not referring to HPV.