Unlike smoking, or excessive gambling and drinking, eating junk food does not directly impair the well-being of anyone else.

ECONOMIST: Does a tax on junk food make sense?

It seems logical that couch potatoes eating junk food will gain weight.

NPR: Study Offers New Insights into Obesity

Neither is drinking lots of alcohol, driving fast or eating junk food.

ECONOMIST: Blowing smoke

You can do more than just nag him or her about eating too much junk food.

CNN: How to fight childhood obesity in 3 steps

"We know people are eating a lot of junk food, but to have almost one-third of Americans' calories coming from those categories is a shocker, " Bock told Reuters.

FORBES: Chewing The Fat On Obesity

Just as the abundance of junk food means that people have to be more disciplined about their eating habits, so the abundance of junk information means they have to be more disciplined about their browsing habits.

ECONOMIST: Schumpeter

The staff also ensured Mr. Huckabee had healthy food around while everyone else was eating junk.

WSJ: The Politics of Gov. Chris Christie's Weight

Having dedicated his career to discovering the root causes of illness, to hear him talk and to see his slides was enough to make even the most ardent junk-food aficionado rethink his or her eating habits.

FORBES: Can The Nantucket Project Change Who We Are?