This study below that I gleaned from the LA Times shows that just altering your diet may not be able to undo a life of bad eating. Maybe if they included exercise in these peoples lives it may have made a bigger difference to their health.
Overturning three decades of conventional wisdom, a new study of low-fat diets in nearly 50,000 healthy older women has shown that reducing fat intake alone does not significantly reduce the risk of heart disease, stroke, breast cancer or colorectal cancer, researchers reported today. Results from the same study reported last month also showed that reducing fats without reducing calories does not lead to significant weight loss.
“Just switching to low-fat foods is not likely to yield much health benefit in most women,” said Marcia Stefanick, a professor of medicine at the Stanford Prevention Research Center, chairwoman of the steering committee for the Women’s Health Initiative study.
“Rather than trying to eat ‘low-fat,’ women should focus on reducing saturated fats and trans fats,” the so-called bad fats, while maintaining their intake of “good” fats, such as vegetable, olive and fish oils.
“Nutrition knowledge has progressed dramatically since the study began,” said Mara Vitolins, a professor of public health sciences at Wake Forest University Baptist Medical Center in Winston-Salem, N.C., and a study co-author. “Today we know that reducing total fat may not be enough — we need to focus on the types of fat we eat.”
The 13-year study, whose results will be reported Wednesday in three papers in the Journal of the American Medical Assn., did hint at some possible benefits from reducing fat intake. Women on the low-fat diet who had the highest consumption of fats at the beginning of the study showed the biggest decrease in breast cancer risk. And those who achieved the lowest rate of fat consumption showed the lowest risk of heart disease. And those who reduced fat intake had a lower incidence of polyps, generally considered to be a precursor of colorectal cancer.
In each of those cases, however, the reductions were not statistically significant, meaning that they could have occurred by chance. In part, that may be because the women in the study have only been followed for eight years, on average, said Dr. Rowan T. Chlebowski of the Los Angeles Biomedical Institute in Torrance, a study co-author. “I’m cautiously optimistic that, with a few more years of follow-up, there may be something,” particularly for breast cancer, he said.
The study also found that the diet, which included increased consumption of carbohydrates and grains, is safe and healthful — contradicting the claims of proponents of low-carbohydrate diets, such as the Atkins diet, that high carbs increase the risk of diabetes. The women in the study “did not show any signs of diabetes, their triglycerides were normal, and their blood glucose was normal,” said Dr. Elizabeth G. Nabel, director of the National Heart, Lung and Blood Institute, which sponsored the $415-million study.
When the study was conceived in the 1980s, fat was perceived as a universal villain. For control, it was a problem because of its high energy density — 9 calories per gram, compared to 4 calories per gram for carbohydrates. For cardiovascular disease, fats were known to play a major role in the buildup of artery-clogging plaque, while the role of protective vegetable fats had not yet been recognized. Studies of women in countries with low-fat diets showed a lower incidence of breast cancer, which rose when the women migrated here and began consuming a Western diet. And red meats had been linked to colorectal cancer, presumably because of their high fat content.
Plus, said Nabel, “we realized most clinical trial results came from men, and that we had very little information about health as it related to women.”
For the current study, 48,835 healthy women with an average age of 62 were enrolled. Forty percent of them were given intensive counseling to help them reduce their fat intake, while the remainder continued with their normal diet. Even with the counseling, most women were not able to reduce fat consumption from the average of 35% of their calories at the beginning of the study to the target of 20%. At the end of the first year, their fat consumption was 24% of calories, while by the sixth year it had inched back up to 29%.
That lower adherence to the diet than planned was, in part, “why we don’t have definitive results yet,” said biostatistician Ross Prentice of the Fred Hutchinson Cancer Research Center in Seattle. The study did not differentiate between different types of fat.
Prentice cautioned that the subjects were all “very healthy women who were already following most of the [government’s] dietary guidelines,” so their ability to decrease risk by lowering fat may have been low. “Unhealthy women may gain more benefit.”