DESPITE a book deal that could bring her millions, infamous White House intern MONICA LEWINSKY appears more lost and lonely than ever– and sources say she’s packed on a whopping 50 pounds due to chronic overeating!

Medical experts say that the added weight puts her at risk for a wide range of ailments, including “many forms of cancer.”

Exclusive ENQUIRER photos taken in New York City on Oct. 6 confirm the sorry state of the 39-year-old former intern and her latest battle of the bulge.

“With a book deal worth a reported $12 million, Monica should be on top of the world,” said a friend. “But she seems sadder than ever and is turning to food as a crutch.”

Sources say that troubled Monica – who’s set to reveal shocking new secrets about her affair with former president Bill Clinton in a bombshell memoir – now tips the scales at nearly 275 pounds.

That qualifies her as morbidly obese, according to medical ex­perts, who warn that Monica’s weight puts her at increased risk of diabetes, heart disease, high blood pressure and many forms of cancer.

“She’s a walking time bomb,” said Dr. John McDougall, found­er of the renowned health plan known as the McDougall Program. “Obesity puts her at risk for Type 2 diabetes and osteoarthritis of hips, knees and ankles.”

Monica could also be at increased risk of breast and uterine cancer, infertility, heart disease, stroke and Parkinson’s disease, he added.

One expert even recommends that Monica undergo surgery to control her weight!

“Based on her height and weight, she is clinically morbidly obese,” Dr. Carson Liu, a Santa Monica, Calif., bariatric surgeon told The ENQUIRER. “If she has trouble managing her eating habits, I’d recommend weight-loss sur­gery.”

Meanwhile, bulky Monica can’t seem to shake her blues de­spite her blockbuster book offer.

“Her overall body language suggests sadness and insecu­rity,” said Dr. Lillian Glass, au­thor of “The Body Language Advantage,” who analyzed The ENQUIRER’s photos of her.

“Her facial expressions show no sign of happiness. Instead, her jaw is clenched and she looks numb. She also exhibits inappropri­ateness in her choice of footwear by donning sandals on a cold, rainy fall day in New York.

“Overall, I’d say she’s exceedingly sad as well as inse­cure about her physical appearance.”

Her friend added: “Monica’s close to turning 40, she has no man in her life, and she’s been living with her mother because she couldn’t afford to live on her own.

“And hovering above all this is the pathetic fact that she’d never been able to fall out of love with Bill Clin­ton. She worships and despises him at the same time.”

Now, it seems she’s turned to food as a crutch.

“These days, it’s not unusual for Monica to fin­ish off a large meal with several des­serts,” noted the friend. “She has a particular weakness for chocolate mud cake, key lime or sour cream apple walnut pie and bread pud­ding with whipped cream.”

Back in 1994, 5-foot-6 Mon­ica weighed 135 pounds, according to her driver’s li­cense. But by 1999, a year after the so-called “Zip­pergate” scandal exploded, she bulked up to a hefty 175 pounds.

Desperate to slim down, she signed a deal as spokeswoman for Jenny Craig and reportedly lost 31 pounds, but then became frustrated by her inabil­ity to shed any more weight and was dropped by the diet company.

Monica – cruelly dubbed a “portly pepper pot” – fell back into her old eating habits and hit almost 300 pounds.

By late 2004, she was down to 260 pounds after spending time at the Grail Springs Health Retreat and Wellness Spa in Bancroft, Ontario, Canada. Her weight has fluctuated since then but has been on a recent upswing.

“Unfortunately, my appetite doesn’t dis­criminate against my moods,” Mon­ica once admitted. “Happy or sad, I love to eat.”

Another source said: “When you see Monica these days, you can’t help but notice the pain that seems to emanate from her. Maybe her new book will finally allow her to release her demons – and get her life, and her weight, in check.”