Some physicians are calling it the "Rolls Royce" of medical studies.
In the largest study ever of its kind, researchers spent eight years and $415 million compiling the startling results.
It followed nearly 49,000 women aged 50 to 79, half of whom were put on a low-fat diet.
The results are disappointing; the low-fat diet did not reduce the rate of heart disease, breast cancer, or colon cancer. But many doctors and dieticians remain skeptical of the findings.
"The study is really not significant in my opinion," said Kathryn Schultz, a clinical dietitian at Ingham Regional Medical Center. She said she isn't impressed with the study by the Journal of the American Medical Association. "You have to read beyond the study and see its kind of a silly way to report it," she said.
Schultz's colleague Cheryl Martin, another dietitian at Ingham, agrees. She said the study is not a green light for people to start eating whatever they want.
"In the long run, a moderate diet with high fruits and vegetables is still healthy for all types of disease," Martin said.
At the start of the study, the average woman got about 37 percent of her daily calories from fat. The goal was to reduce that number to 20 percent. But by the end of the study the average woman was only able to lower it to 29 percent.
"You really can't say a 29 percent diet is a 'low fat' diet," Martin added.
Many physicians also say the study isn't valid because it's not realistic that 49,000 women can accurately keep track of everything they eat over an eight-year period.