But, as CBS News Correspondent Cynthia Bowers reports, what a nutritionist would call a recipe for heart attacks is just what one doctor ordered for Izabela Strepak.
She went from a size 14 to a size 4.
"I guess that's a lot," she says.
"We have in our heads - our brain - that fat is bad for you," says Strepak. "Fat is good for you, actually."
The "fit through fat" idea comes from Poland and Dr. Jan Kwasniewski. After decades of working as a dietician in a military hospital, he wrote a book called the "Optimal Diet," an even higher-fat, low-carb Atkins-like regimen. He said the diet works because the animal fat provides energy.
He's talking about eating 250 grams per day, three times more than most health guidelines. To eat that much you have to start early. Breakfast would require a four egg-yolk omelet cooked in lard, a side of bacon and sausage, toast bathed in butter - all washed down with a cup of heavy whipping cream. And that's just a third of your fat goal.
In what passes for the diet's American headquarters - a small market in a heavily Polish Chicago neighborhood - Tomasz Zielinski sells everything you need for the Optimal lifestyle: veal brains in aspic (14 percent fat), spicy lard (62 percent fat) and bread (43 percent fat).
Lucyna Biganski says she could barely walk before she started the diet.
"It's a change of style of life," she says. "It's not only for a week (or) a month.
"You lose weight, you feel better - that's it."
With only a handful of followers in the U.S., don't look for the Optimal diet to replace South Beach or Atkins anytime soon. While cardiologists cringe, if you believe the faithful and can stomach it, fat may be a new fad.