This does not constitute a green light, of course, to rush right out and gobble down giant chunks of cheese. As researchers are quick to point out, there are still significant health benefits to eating a low-fat, high fiber diet, including reduced risk of diabetes and heart disease. And there are still plenty of scientists and doctors who would like to see a decade-long study on high-fiber diets before calling them off for patients at risk for colorectal cancer. But preliminary as it may be, the message from the Journal article serves to validate the concerns of many in the medical community. "There are a lot of assertions being made about the disease-fighting capabilities of various foods and supplements," says TIME medical contributor Dr. Ian Smith. "And most of those claims remain totally unsubstantiated by long-term studies." In that light, it's important to take every new proclamation about diet with a grain of salt, Smith continues. "Before we allow our hopes for disease prevention to run away with our common sense, we need to see hard evidence to support all the claims that are made."
You can put down that super-size bowl of bran flakes. According to an article published in Thursday's New England Journal of Medicine, it looks as if our national obsession with all things fiber may not be yielding the results we'd hoped for, particularly in the realm of colorectal cancer. The Journal report describes two multiyear studies in which half the 3,000 subjects suffered through an eternity of low-fat, high-fiber diets, while the other half went happily on their way eating their usual (read: low-fiber) foods. In a development that more than one researcher calls "shocking," members of the high-fiber group were no slower than their ostensibly less healthy counterparts to develop colorectal polyps often a precursor to cancer.