http://www.nytimes.com/2002/07/13/o....html?tntemail0
A Diet Rich in Partial Truths
By DEAN ORNISH
AUSALITO, Calif. — In Woody Allen's movie "Sleeper," a man wakes up 200 years in the future to find that science has proved deep-fried foods to be healthy. Is the future here already?
By now, many Americans are thoroughly exasperated by the seemingly contradictory information in the press about what a sound diet is. Lately, I hear many people say, "If the doctors can't make up their minds, I'll eat whatever I want and quit worrying."
That would be unfortunate. Science can help people distinguish what sounds good from what's real. Nowhere are the claims more conflicting than in the area of diet and nutrition. Unfortunately, this is an area where misinformation can make a huge difference to an individual's health and well-being.
The high-protein diet (which is almost always high in fat), for example, has become very popular; just about everyone knows someone who has lost weight on this kind of diet. Given the American epidemic of obesity, isn't that a good thing?
Not necessarily. You can lose weight with fen-phen, too, but that doesn't mean it's good for you. When you go on a high-protein, high-fat diet, you may temporarily lose weight — but you may also mortgage your health in the process. The only peer-reviewed study of the effects of a high-protein diet on heart function found that blood flow to the heart actually worsened and heart disease became more severe.
But high-protein diets help people lose weight because they are based partially on science, which is what makes them seductive. The high-protein advocates are right when they say that people in the United States eat too many simple carbohydrates like sugar, white flour and white rice. These foods are absorbed quickly, causing blood sugar to spike, which in turn provokes an insulin response that accelerates the conversion of calories to fat. There is a clear benefit to reducing the intake of simple carbohydrates, especially to people who are sensitive to them.
So the diagnosis is correct: we are eating too many simple carbohydrates. But the cure is wrong. The solution is not to go from simple carbohydrates to pork rinds and bacon, but from simple carbohydrates to whole foods with complex carbohydrates like whole wheat, brown rice, and fruits, vegetables, grains and legumes in their natural forms.
These foods are naturally high in fiber, which slows their absorption, preventing a rapid rise in blood sugar. Fiber also fills you up before you eat too many calories, whereas you can eat large amounts of sugar without feeling full. Best of all, these foods contain at least 1,000 substances that have anti-cancer, anti-heart disease and anti-aging properties.
For the past 25 years, my colleagues and I have conducted a series of randomized studies demonstrating that this whole-foods diet can reverse the progression of even severe heart disease in most people. These results have been published in the leading peer-reviewed medical journals. On average, our patients lost 24 pounds and kept more than half of that off for at least five years.
We demonstrated in hospitals throughout the country (including places where we were told that gravy is a beverage) that most heart patients were able to safely avoid bypass surgery or angioplasty by following this diet combined with moderate exercise, stress management techniques and participation in support groups. Medicare is now paying for 1,800 patients to go on this diet. Recently we found that this program may stop or reverse the progression of early prostate cancer as well. The more closely people followed the diet, the more their heart disease reversed and the lower their prostate-specific antigen, a marker for prostate cancer, became.
It's not that fats are bad; we just eat too much of them. Fish oil and flaxseed oil are very good for you because they provide the kind of fatty acids that can substantially reduce the incidence of sudden cardiac death and may help prevent some forms of cancer, but you only need a few grams a day. And because fat has more calories per gram than protein and carbohydrates, when you eat less fat, you consume fewer calories without having to eat less food.
Science can help us sort out conflicting claims. Researchers now are studying the effects of high-protein diets. It would be wise to wait for these results rather than discouraging people from making dietary changes that have been medically proved to be so beneficial.
Dean Ornish is president of the Preventive Medicine Research Institute and a clinical professor of medicine at the University of California, San Francisco. He is the author of "Eat More, Weigh Less.''