In his procrastination speech, Charles Duhigg explains the only way in which to limit Facebook and other non-productive habits is to allow them. In fact, he advises setting aside five minutes per hour in order to do so.
The New York Times reporter explains in his procrastination speech that by giving yourself a small amount of time for leisure you will not be denying yourself. This behavior can actually lead to an outburst of even greater distraction. People possess habits that can't just be switched off overnight. He explains that once the procrastination habits are under control, it will be much easier to diminish them. The brain will get into a routine and it can slowly build pathways by which to eliminate the need for procrastination at work.