TODAY | May 08, 2013
>>> 7:50 with new details on governor chris christie 's weight loss surgery . is he speaking out now in a "rock center" exclusive about why he decided to have the procedure.
>> i needed to do something.
>> the 50-year-old governor told brian williams he decided to pursue the surgery for the sake of his family after other efforts to lose weight were unsuccessful.
>> i did not want to take the risk of becoming unhealthy and the ramifications that would have for mary pat and for my four kids and i still have children in elementary school so i got a long road here as a father and i don't want to miss any of it.
>> reporter: after years of listening to david letterman poke fun at his weight, christie got in on the joke just two weeks after his surgery.
>> i didn't know this was going to be this long.
>> reporter: on tuesday there were more late night laughs at christie 's expense.
>> new jersey governor chris christie has revealed back in february, he had a secret lap band surgery . which explains why there's been so much food in new jersey lately.
>> reporter: christie sought advice from bariatric surgeon dr. george fielding and consulted rex ryan , the new york jets head coach who had successful lap band surgery himself.
>> the biggest thing about it for me is i'm just not very hungry anymore. that's a huge change.
>> and you can see more of brian williams 's interview with chris christie on "rock center" friday night at 10:00 , 9:00 central time on nbc.