Now, Ms. Deen, 64, has brought to her own table a multiplatform endorsement deal with Novo Nordisk, the Danish pharmaceutical company that makes Victoza, an noninsulin injectable diabetes medication that she began promoting on Tuesday morning. She and her sons, Jamie and Bobby (who do not have diabetes), are all being paid to spearhead the company’s upbeat new public-relations campaign, “Diabetes in a New Light,” which advocates using the drug along with eating lighter foods and increasing physical activity. All the same, Ms. Deen said she would not change her own lifestyle or cooking style drastically, other than to reduce portion sizes of unhealthful foods. “I’ve always preached moderation,” she said. “I don’t blame myself.”

Bobby Deen, who was at his mother’s side throughout the day, has a new healthful-cooking show, “Not My Mama’s Meals,” that began last month. Through a spokeswoman, the Food Network said that that it did not know of Ms. Deen’s illness before last week.

Ms. Deen’s announcement, delivered with the liveliness of the head cheerleader she was back in 1965, testified to her savvy as an up-from-the-roots businesswoman, turning a setback into a fresh opportunity with a series of news media appearances that played out through the day. Andrew Essex, head of the New York marketing agency , which advises candidates and companies on branding, said Ms. Deen’s bid for transformation was ambitious.

“There’s no question that she was the face of a certain kind of egregious indulgence,” he said. “If she can now become the face of healthy living, it will be a Gatsby-esque turnaround.”

Her revelation also adds a fresh story line to a roiling national debate about obesity, with elements of celebrity, schadenfreude and the current popular favorite, class warfare. And it comes as the Food Network prepares next week to broadcast “Fat Chef,” a new reality show that illustrates the difficulty many cooks have in managing the temptations and nutritional pitfalls of the job.

Thousands of Ms. Deen’s fans tweeted their support and posted messages of sympathy on her Facebook wall Tuesday. But many others questioned her motives in concealing the condition for so long, or said they spotted hypocrisy in her decision to profit from an illness that they believe she had abetted. On Facebook, Dolly Furst of Pennsylvania posted: “Sorry Paula. I think you hid the disease because the network thought people would dump your show.”

Katherine Pietrycha wrote: “These deals don’t get done overnight. I think she’s known for quite some time she’s had this, and in the meantime, has been pushing recipes filled with sugar and fat.”

A chorus of “told you sos” sprang up on the blogosphere.

“No wonder she has diabetes,” tweeted Jennifer Eure, who lives in Franklin, Va., during “Paula’s Home Cooking” on Monday as Ms. Deen discussed what kind of breadsticks to pair with bacon cheese fries.

More than 25 million Americans, or about 8.3 percent of the population, are believed to have diabetes, most of it Type 2 or “adult onset” diabetes. Like those other cases, Ms. Deen’s illness was probably caused by any of a number of forces, including excess weight, high blood pressure, lack of exercise and high blood levels of sugar, fat and cholesterol. But unlike her fellow patients, Ms. Deen is now enduring an epic public scolding because of her cooking and eating habits.

Heredity, according to the American Diabetes Association, always plays some part. “You can’t just eat your way to Type 2 diabetes,” said Geralyn Spollett, the group’s director of education. But, Ms. Spollett added, Southern cooking, as often practiced, can be particularly hazardous to those predisposed to the disease. “There’s no denying that Paula’s food has a lot of what we call the deadly triangle: fat, sugar and salt,” she said.

Ms. Deen would not say what she thought had caused her illness. But she said she takes the drug she is promoting, Victoza.

Dr. R. Paul Robertson, an endocrinologist at the University of Washington, said that Victoza, which helps stimulate insulin production, offers weight-loss benefits that other diabetes medications do not. Those who use it feel full faster, he said, though it is unclear why.

 The drug’s only drawback, he said, and the reason it is not a first-line diabetes medication, is its high cost: about $500 a month at the normal therapeutic dose.

Ms. Deen admitted to making one dietary change: she has entirely given up sweet tea, the classic Southern pairing for everything from barbecue to fried chicken. (A cup of sweet tea, made according to Ms. Deen’s recipe, contains just under a tablespoon of sugar.)

Ms. Deen, who began her career selling bag lunches to office workers in Savannah, Ga., has long been a lightning rod in the food world, criticized not only for using fattening ingredients, but also for perpetuating negative stereotypes about Southern cooking, endorsing products from the giant pork producer Smithfield, and using her culinary following to sell an array of items from her husband’s coffee brand to bedroom furniture. (“You can definitely tell that these mattresses have been inspired by my life in the South,” she says on the Serta Web site.)

Last summer, the chef Anthony Bourdain, a fellow food-TV celebrity, said in a TV Guide interview that Ms. Deen’s fatty food made her “the worst, most dangerous person” on the Food Network.