Study Finds Low-Fat Diet Won't Stop Cancer or Heart Disease - New York Times

Study Finds Low-Fat Diet Won't Stop Cancer or Heart Disease - New York Times: "A lot of observational data show diet matters, but those studies have big flaws and that's why we have to do experiments,' Dr. Freedman said. 'We, the scientific community, tend to go off the deep end giving dietary advice based on pretty flimsy evidence.'

Dr. Jules Hirsch, physician in chief emeritus at Rockefeller University, agreed. 'These studies are revolutionary,' he said. 'They should put a stop to this era of thinking that we have to all the information we need to change the whole national diet and make everybody healthy.'

For decades, there has been a widespread belief that what you eat — the composition of the diet — determines how likely you are to get a chronic disease. But it has been hard to prove. Studies of dietary fiber and colon cancer failed to find that fiber was protective. Studies of vitamins thought to protect against cancer failed to show an effect. Gradually, an increasing number of cancer researchers began questioning the dietary fat-cancer hypothesis, but it has retained a hold on the public imagination.

Some medical experts said they expected that the results would be met with disbelief. The conclusion, after all, was that the composition of women's diets had no appreciable effect on their health.

That goes against deeply ingrained notions, Dr. Libby said. "Nothing fascinates the American public so much as the notion that what you eat rather than how much you eat affects your health," he said.

But Dr. Thun of the American Cancer Society said that now, with results that he describes as "completely null over the eight-year follow-up for both cancers and heart disease," his group has no plans to suggest that low-fat diets are going to protect against cancer.
But the overall message, said. Barbara Howard, an epidemiologist at Medstar Research Institute, a nonprofit hospital group and a principal investigator in the federal study, was clear. "We are not going to reverse any of the chronic diseases in this country by changing the composition of the diet," Dr. Howard said. "People are always thinking it's what they ate. They are not looking at how much they ate or that they smoke or that they are sedentary."