Corporate debt is a bit like the piece of ricotta torte I had for dessert last night: it goes down very easily, but chronic overindulgence will constrict the arteries, strain the heart, and possibly even kill you. And that’s exactly what is happening to Lee Enterprises, which publishes nearly 50 daily newspapers including the North County Times in San Diego County.

Lee Enterprises swallowed a staggering amount of debt over three years ago when it bought Pulitzer Inc., publisher of more than a dozen daily papers including the St. Louis Post Dispatch, founded in 1879 by Joseph Pulitzer. That turned out to be a disastrous move, as Lee is now in grave condition. Nearly 10,000 employees may find that come April, their employer can no longer survive in its present condition.

I decided to write about Lee after a friend who works for the chain asked what I thought of the company’s finances. Management was sugarcoating things, and my friend had no idea where things stood. (Full disclosure: I worked for the Lee owned Quad-City Times in the 1990s.)

Reading the company’s Dec. 31st 10-K filing led me to the conclusion that Lee Enterprises is already dead. A balloon payment of $306 million dollars is coming due April 28 and Lee, which posted a loss of nearly three times that amount last year, has flat-out admitted that it doesn’t have the cash.

The newspaper company can’t borrow its way out of this because its lenders have put it on a strict debt diet — no more sweets for you, Lee! They can’t borrow, they don’t have the cash, so Lee is left with few options. The company could sell assets to pay down debt but there’s not much of a market these days. Another option is a debt-for-equity swap, with the lenders becoming owners of the company.

Ultimately, it comes down to this: Either institutional investors that hold the secure notes will show mercy, or a bankruptcy judge will have to carve up the company’s bloated corpse and sell off the parts.

Lee’s stock closed at 56 cents today, down from $15 a share a year ago, and many on Wall Street think it hasn’t hit bottom. Lee’s short interest, a measure of pessimism in the company’s future, is one of the highest for any publicly-traded U.S. firm.

The Davenport, Iowa-based company’s difficulties are a symptom of the pain experienced by newspaper chains that used debt to finance growth in recent years. Tribune Corp., publisher of the Los Angeles Times and the Chicago Tribune, is in bankruptcy. McClatchy Corp., which loaded up on debt to buy Knight-Ridder in 2006, is struggling for survival.

When it acquired the St. Louis Post Dispatch in 2005 for $1.5 billion, Lee also assumed a $306 million debt, which is a twisted tale in itself.  Pulitzer borrowed the money in 2000 to gain control of the Post Dispatch and buy out almost all of the stake held by the Newhouse family’s Advance Publications. (Privately-held Advance owns Conde Nast, publisher of The New Yorker, Vanity Fair and others, and also publishes major metro dailies in Portland, Ore., and New Orleans.)

For 16 years, Pulitzer had been paying Newhouse half of the Post Dispatch’s profits under a “joint operating agreement” with a newspaper that no longer existed. Newhouse sold the St. Louis Globe-Democrat in 1984, and somehow got Pulitzer to keep paying it, even after the Globe-Democrat stopped printing a few years later. (Newhouse still gets 5 percent of the Post Dispatch profits.)

The bad news doesn’t end in April because the Putlitzer debt just keeps on dealing out pain. The $306 million is only the principal on the loan, which carries 8.05 percent interest annually. So the total bill is more than $600 million. And counting.

That’s the story of how a bad deal to buy out one newspaper chain is about to destroy two others.