Bill Clinton is killing himself with fast food and alcohol - because those close to him fear he's refusing to change the bad habits that caused his recent medical crisis.

Just days after being released from a New York hospital post-heart surgery, Clinton was back in his office working an 18-hour day, eating fried chicken and barbecued ribs and washing it down with Red Stripe beer, a source told The ENQUIRER.

The problem has become so serious, according to the source, that daughter Chelsea is thinking about staging an intervention.

"Bill has never been a big drinker, but since he left the White House - and that incredible burden was lifted off his shoulders - he started drinking more and has found he likes it," said the source.

While Bill's family and friends are aware he has a problem, they have no idea how serious it really is, says the source.

"He then tries to hide the evidence from his family, " adds the source, "out of the back of the car."

For the full story with all the details of the the ex-prez's orgy of food and booze, pick u the new ENQUIRER