Review of popular diets finds many aren't very healthy

Two reports -- one from the public sector, one from the private -- find there is still no quick trick for patients who want to slim down.

By Kathleen F. Phalen, amednews correspondent. Jan. 29, 2001.

Now that the last of the eggnog, holiday cookies and honey-glazed Brie are gone, it's time to get serious about losing weight. Or at least time to start thinking about ditching those burdensome extra pounds that have been hanging on for the past few years. Although success seems attainable in January, the New Year visions of thinness can quickly become illusions and then the four-cheese, everything-on-it pizza again takes over.

The desperate may ask their doctors for help, but it's more likely they'll try to go it alone, at least initially. Their search for the golden cure often begins with the latest fad, diet book or advertised plan.

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Some hope the answer lies in the no-sugar, no-carbohydrate, all-meat regimens; others seek a pill, an herb or the latest cellulite cream. Although there are tales of success, there are many failures. And what about those who lose 50 pounds only to gain back 70?

With such conflicting information, patients need guidance. And, although it may seem a daunting task, doctors can help them get on the right track.

Both the U.S. Dept. of Agriculture, the federal agency that developed the traditional "food pyramid" and is charged with the responsibility to be the nation's nutritional watchdog, and the Physicians Committee for Responsible Medicine, an organization that advances low-fat, low-cholesterol diets that move away from meat and dairy, offered separate sets of hints this month that may provide some nutritional guideposts.

Talking to the patient comes first, says Neal D. Barnard, MD, president of the PCRM, a nonprofit Washington, D.C.-based organization that promotes preventive medicine and nutrition. "Some patients may not ask for help and if they are significantly overweight, we have to address it." Dr. Barnard has been researching the effect of diet on health for many years. "To neglect it is indefensible."

Still, Dr. Barnard says it's useful for physicians to know their limits when it comes to helping patients lose weight. "Don't say, 'Just eat less and exercise more.' " Instead, he recommends that doctors write a diet prescription: the type of diet the patient should follow; referral to a registered dietician; regular exercise; stress reduction; and re-check in three weeks.

Like a chest x-ray

He likens it to a chest x-ray. The doctor doesn't do the x-ray, but directs the patient to have one and then follows up. It's the same approach. "Tell the patient, 'I want you to follow an Ornish-type (or other) diet and here's someone who can help.' That takes the heat off," says Dr. Barnard, who believes dieticians are an invaluable support. "Then invite your patients to come on Tuesday nights for recipes in your waiting room. Get a dietician to come in and do a presentation. Your patients will adore you."

To make dieting decisions easier and more informed, PCRM in January released information on the health effects of the most popular diets. Only two of the 11 top-selling books got PCRM's top rating: Eat More, Weigh Less, by Dean Ornish, MD, and The McDougall Program for Maximum Weight Loss, by John McDougall, MD. Both promote low-fat vegetarian diets, high in fiber and low in cholesterol. An unsafe rating went to two other best-sellers: Dr. Atkins' Diet Revolution, by Robert Atkins, MD, and The Carbohydrate Addict's Lifespan Program, by Richard Heller, PhD, and Rachel Heller, PhD.

PCRM rated each book's daily diet recommendations on five criteria: a minimum of 25 g of fiber, five servings of fruits and vegetables, no more than 50 mg of cholesterol, no more than 30% of total calories from fat and no more than 10% from saturated fat. "These are basic dietary recommendations and I was surprised how many didn't make the cutoff," says Brie Turner-McGrievy, MS, RD, staff dietician at PCRM. Turner-McGrievy helped analyze the diet books and is currently involved in a diet research study at PCRM that compares the low-fat, vegan, McDougall diet with the National Cholesterol Education Program Step Two diet.

Meanwhile, also in January, the USDA released a separate evidence-based review of popular weight-loss programs and their effects on health. According to the report, all diets that reduce caloric intake result in weight loss: "In the absence of physical activity, a diet that contains about 1,400 to 1,500 kcal per day, regardless of macronutrient composition, results in weight loss." The caveat, according to the report: "Weight loss is not the same as weight maintenance."

Based on a review of existing scientific evidence, the USDA concluded that moderate, traditional diets like those recommended by the American Heart Assn. and Weight Watchers -- no more than 30% of calories from fat, no more than 20% from protein, along with plenty of fruits, vegetables and complex carbohydrates -- are the most nutritionally sound. This conclusion parallels the existing USDA Food Pyramid and Dietary Guidelines for Americans, which advocate a diet consisting of a whole-grain base and fewer daily servings of meats, fats and dairy.

Dietary programs like the Atkins diet, which advocates high protein and low carbohydrate consumption, also did not fare well in the USDA report. "It doesn't mean these diets [high protein, high fat] don't work, but there is no evidence," says Xavier Pi-Sunyer, MD, chief of endocrinology at St. Luke's-Roosevelt Hospital Center in New York.

Dr. Pi-Sunyer says that existing evidence shows that lower-fat, higher-carbohydrate diets are healthier and more effective for the long term. "[But] if the USDA wants to really pursue this, they need to fund clinical trials that put these diets against each other," he says.

ADDITIONAL INFORMATION:

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The U.S. Dept. of Agriculture food pyramid is designed to provide a way for consumers to make healthy diet choices based on typical elements of the American diet. Much of the USDA analysis of current popular diets paralleled the pyramid's components.

Fats, oils and sweets: Use sparingly
Milk, yogurt and cheese group: 2-3 servings
Meat, poultry, fish, dry beans, eggs and nuts group: 2-3 servings
Fruit group: 2-4 servings
Vegetable group: 3-5 servings
Bread, cereal, rice and pasta group: 6-11 servings

A color image of food pyramid guide is available at the Nutrition.gov site (http://www.nutrition.gov/framesets/frameset.php3?topic=food%20facts&subtopic=food%20pyramid).