Your implied intellectual model here is that people are entirely in control of their actions and are (or at least can be) perfectly rational about them.
That's far from the truth. These junk food brands spend enormous amount of money on advertising, product placement, and other ways to influence consumers. Why? Because it works to manipulate them.
Or talk to anybody who works in mass-market advertising. Or hell, just visit Vegas. If people were rational actors, Las Vegas would still just be a place where the Hoover Dam workers lived.
That's far from the truth. These junk food brands spend enormous amount of money on advertising, product placement, and other ways to influence consumers. Why? Because it works to manipulate them.
See, for example:
http://en.wikipedia.org/wiki/Category:Cognitive_biases http://en.wikipedia.org/wiki/Behavioral_economics
Or talk to anybody who works in mass-market advertising. Or hell, just visit Vegas. If people were rational actors, Las Vegas would still just be a place where the Hoover Dam workers lived.