MELISSA BLOCK, host:
If you're among millions of Americans struggling to shed those extra pounds, we've got a study for you. Grab a pen and pad; you might want to take notes. Four of the most popular diets are compared and contrasted in the current journal of the American Medical Association.
NPR's Patty Neighmond reports.
PATRICIA NEIGHMOND: Today, you can walk into a bookstore and probably find dozens of diet books. But is a popular diet book all the help you need to lose weight? That's what researchers at Stanford University wanted to know. They compared the Atkins diet, high protein and low carbs, the Zone, also low carb but not as low as Atkins, LEARN, which stands for lifestyle, exercise, attitudes, relationships and nutrition and is the most commonly recommended diet by health professionals, and the Ornish diet, higher in carbs but very low in fat.
Nutrition scientist Christopher Gardner and colleagues found the answer to their question.
Dr. CHRISTOPHER GARDNER (Assistant Professor in Medicine, Stanford University): Reading a book and doing it on your own, even if you understand it, isn't enough.
NEIGHMOND: Gardner says routine counseling with a dietitian is what many overweight individuals need. In the study, 311 women who were 15 to 100 pounds overweight were assigned to one of the four diets. Gardner looked at the women's health and weight after one year.
Dr. GARDNER: Throughout the whole trial, the Atkins group, the very low carbohydrate group, lost about twice as much weight throughout.
NEIGHMOND: But twice as much wasn't really very much. On Atkins, the average weight loss after a year was 10 pounds. On LEARN, Zone and the Ornish diets, the women lost three to six pounds. But their health improved. Anyone who lost any weight at all also lowered their cholesterol, triglycerides and blood sugar.
What are the reasons why the Atkins dieters did better? For one, more of them stuck to the diet. And Gardner says that could be because the Atkins diet is so simple.
Dr. GARDNER: Just drastically reduce your carbohydrate, and completely eliminate any sugary - any sodas, any high-fructose corn syrup, any white bread, any white rice.
NEIGHMOND: It could also be that the Atkins diet keeps you full longer. Walter Willett is a medical nutritionist at Harvard's School of Public Health.
Dr. WALTER WILLETT (Nutritionist, Harvard School of Public Health): When people eat large amount of carbohydrate, those kinds of foods leave you hungry. And a few hours after eating, we usually are looking for something to eat again.
NEIGHMOND: Food with protein and fat keeps dieters satisfied for a longer period of time. And dieters in the Atkins group did eat higher levels of fat, even saturated fat, than dieters in the three other groups. So does that mean it's okay to eat high levels of animal fat?
Gardner says on a short-term basis, it wasn't a problem. After one year, the women didn't end up with higher levels of cholesterol. In fact, levels went down as they lost weight. Gardner says that losing weight did them more good than eating saturated fat did them harm. But Gardner also says he doesn't know if the Atkins diet is healthy over the long term.
Dr. GARDNER: Five, 10 years out, is a low carbohydrate protein diet, good for kidney function? Good for bone density? We actually have some concerns. Is a long term low carbohydrate at the time saturated fat good for you? Probably not, but we really only have one-year data and we have to look longer.
NEIGHMOND: Nutritionist Walter Willet says there is a way to make high fat healthy.
Dr. WILLET: And that's to eat lots of vegetables, use healthy fats like olive oil and most vegetable oils - and they'll make the vegetables taste better, by the way. For protein sources, we could use nuts, some beans and some fish and poultry in moderation.
NEIGHMOND: Willet says that even Dr. Robert Atkins himself came around to viewing healthy vegetable fats as better than animal fats, and Willet says other research has found diets rich in vegetable fats actually do decrease heart disease and diabetes.
Patty Neighmond, NPR News.
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