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Ornish Diet

dimanche 5 octobre 2014 | 14:10

The aim:

Variable. Can be tailored to losing weight, preventing or reversing diabetes and heart disease, lowering blood pressure and cholesterol, and preventing and treating prostate or breast cancer.

 The claim:  It’s scientifically proven to make you “feel better, live longer, lose weight, and gain health.”

The theory: The more you change your diet, the more health benefits you reap. If you’re only looking to lose a few pounds, a couple of this-for-thats might do the trick. But if you want to reverse heart disease—which research shows may be possible at the rigorous end of this diet’s spectrum of choices—you’re looking at big changes. For most programs, though, you have plenty of room between all and nothing. If you indulged yesterday, make more healthful choices today; if you didn’t have time for a run yesterday, make it a must-do today. What matters most is your overall approach—if it’s doable and pleasurable over the long haul, you’ll stick with it for life.

How does the Ornish Diet work?

Through his 2007 book The Spectrum, Dean Ornish—a professor of medicine at the University of California, San Francisco, and founder of the Preventive Medicine Research Institute in nearby Sausalito—lays out your nutrition, exercise, stress management, and emotional support options as a guide toward achieving any goal, from weight loss to preventing or reversing chronic diseases.
On nutrition, Ornish categorizes food into five groups from most (group 1) to least (group 5) healthful. It’s the difference, for example, between whole-grain bread and biscuits, between soy hot dogs and pork or beef ones. Ask yourself what groups tend to fill up your grocery cart, and decide how you want to fill it up. As for exercise, Ornish stresses aerobic activities, resistance training, and flexibility; you decide what you do and when. To manage stress (long a core element of his program), you can call on deep breathing, meditation, and yoga. Find a combination that works for you and set aside some time each day to practice. Finally, Ornish says that spending time with those you love and respect, and leaning on them for support, can powerfully affect your health in good ways.

Ornish applies these “spectrums” to a host of common health problems, dedicating chapters to losing weight, lowering cholesterol and blood pressure, preventing and reversing type 2 diabetes and heart disease, and preventing and treating prostate and breast cancers.
The program to reverse heart disease is the one for which Ornish is best known. Given the ambitious goal, it’s unsurprising that doing it right, at the most healthful end of the spectrum, doesn’t give you much wiggle room. Only 10 percent of calories can come from fat, very little of it saturated. Most foods with any cholesterol or refined carbohydrates, oils, excessive caffeine, and nearly all animal products besides egg whites and one cup per day of nonfat milk or yogurt are banned. Fiber and lots of complex carbohydrates are emphasized. Up to 2 ounces of alcohol a day are permitted, but guardedly. This regimen, combined with stress-management techniques, exercise, social support, and smoking cessation, formed the basis of Ornish’s landmark heart disease-reversal trial in the 1990s. He explains it in more detail in Dr. Dean Ornish’s Program for Reversing Heart Disease (1991).

Will you lose weight?

Perhaps, perhaps not. There are varying degrees of an Ornish diet. But if you’re exercising regularly and have adopted a menu filled with foods from the healthiest three nutrition groups—which emphasize produce, whole grains, and fish—it’s likely.

Here’s a look at some studies analyzing the potential for weight loss on an Ornish diet:
  • In the extension study to Ornish’s landmark heart disease-reversal trial, published in the Journal of the American Medical Association in 1998, researchers reported that a small group of Ornish dieters who followed the plan described in the previous section had lost an average of 24 pounds after a year. At five years, they still maintained a loss of 13 pounds from their original weight. At one- and five-year check-ins, control-group dieters were on average 3 pounds heavier than when they started.
  • In an analysis published in the American Journal of Health Promotion in 2010, about 1,300 participants on the Ornish plan to reverse heart disease decreased their body mass index, a measure of body fat, from 32 (obese) to 29.5 (overweight) after a year. No control group was used.
  • A 2007 study in the Journal of the American Medical Association divided roughly 300 overweight or obese women into groups and assigned them to one of four types of diets: an Ornish approach emphasizing no more than 10 percent of daily calories from fat; low-carb (Atkins); low saturated-fat/moderate-carb (LEARN); and roughly equal parts protein, fat, and carbs (Zone). After 12 months, Ornish dieters had lost an average of 4.8 pounds, the Atkins group had lost 10.3 pounds, the LEARN  group had lost 5.7 pounds, and the Zone group had lost 3½ pounds. Drawing firm conclusions from this study is risky, however. The differences in weight loss among Ornish, LEARN, and Zone participants weren’t statistically reliable. And many participants didn’t follow their assigned diet. The Ornish group, for example, took in up to 30 percent of calories from fat—hardly close to the recommended 10 percent.
  • In another JAMA study, published in 2005, researchers assigned 160 overweight or obese participants to one of four diets: Atkins, Weight Watchers, Zone, and a version of Ornish emphasizing a vegetarian approach with 10 percent of calories from fat. After a year, the Ornish group had lost an average of 7 pounds, which was similar to the range of weight loss (4½ to 7 pounds) in the other groups.
  • Weight loss may not be tied to lower fat intake specifically, however. Many experts maintain that the number of calories you take in—not whether you get them from fat, carbs, or protein—drives weight loss, especially in the long run. In one study, published in 2009 in the New England Journal of Medicine, researchers assigned 811 overweight adults to diets of differing nutrient amounts. At two years, the groups assigned to get 20 percent of their calories from fat had lost about the same as those put on a diet that was 40 percent based on fat.

Does it have cardiovascular benefits?

Without question. Ornish and a team of researchers were the first to show that heart disease, beyond being stoppable, can also be reversed, without drugs or surgery, through changes in diet and lifestyle. In a randomized trial of 48 heart-disease patients published in 1990 in The Lancet, the Ornish program to reverse heart disease reversed artery blockages after one year—and continued to do so after five years. The changes were highly meaningful when compared to a control group, whose condition worsened at both points. The diet has also been shown to lower blood pressure and decrease both total and “bad” LDL cholesterol.

Can it prevent or control diabetes?

Very likely.

Prevention: Being overweight is one of the biggest risk factors for type 2 diabetes. If you need to lose weight and keep it off, and an Ornish diet helps you do it, you’ll almost certainly tilt the odds in your favor.
Control: Because you develop your own plan on the Ornish diet, you can ensure that what you’re eating doesn’t conflict with your doctor’s advice. Ornish’s basic principles of emphasizing whole grains and produce and shunning saturated fat and cholesterol are right in line with American Diabetes Association guidelines.
In the American Journal of Health Promotion analysis cited in the weight-loss section, 329 Ornish dieters decreased their hemoglobin A1C levels—a measure of blood sugar control—by 0.4 percentage points after a year. That was considered meaningful.

Are there health risks?

No. It’s not off-limits to anyone, either. Still, experts advise checking with your doctor before making changes to your diet.

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