"If companies were marketing bananas and broccoli, we wouldn’t be concerned," said one expert in an article about food ads aimed at kids and the obesity epidemic. "But instead, most marketing is for sugary cereals, fast food, snack foods and candy."

Blogger Matt Yglesias asks the obvious followup question: Well, why isn't anyone marketing bananas and broccoli? "This stuff is sold in stores, in exchange for money. Presumably there are for-profit enterprises out there with a vested interest in selling more." It's an interesting enough point to catch the interest of economist Tyler Cowen, who takes a stab at it:

I suspect the core reason is the absence of branding.  "Got Milk?" only gets you so far.  Most promotional campaigns ("green, and really good for you") will benefit all broccoli sellers, rather than any particular brand of broccoli, plus the profit margin on broccoli probably isn't so high anyway.
"Got Milk?" is still around, though. Why is there no "Got Broccoli?"