University of Virginia Health System

New Studies Confirm Benefits Of Atkins Diet

Debate Continues Over Which Eating Plan Is The Healthiest

< May 28, 2003 >Two studies in the New England Journal of Medicine (NEJM) suggest the popular weight-loss plan called the Atkins diet is more effective than a traditional low-fat diet at helping people shed unwanted pounds.

The Atkins approach encourages consumption of high-fat and high-protein foods such as meat and dairy products and discourages consumption of carbohydrates.

Experts: More Study Needed

"The results are very surprising and at the same time very preliminary," says Gary Foster, clinical director of the University of Pennsylvania's Weight and Eating Disorders Program and leader of one of the studies. "The take-home message is that this diet deserves further study."

The results, says a spokeswoman for the Atkins Center in New York City, are confirmation of the views of the physician who created the diet, Dr. Robert Atkins.

"They aren't surprising to us," says Collette Heimowitz, director of education and research at the center. "It's what we've seen in clinical practice for the last few years."

But a critic of the Atkins diet, Dr. David L. Katz, director of the Yale-Griffin Prevention Research Center at the Yale School of Medicine, is concerned by the studies' findings.

The study led by Foster enrolled 63 obese men and women whose average weight was 216 pounds. Some were given a copy of Atkins' "New Diet Revolution," and were asked to follow that diet, which emphasizes fat intake and limits carbohydrates.

Others were given instructions about a conventional weight-loss diet. This diet advised 1,200 to 1,500 calories a day for women and 1,500 calories a day for men. It contained 60 percent carbohydrates, 25 percent fat, and 15 percent protein.

After three months, the average weight loss was 14.7 pounds in the Atkins group, and 5.8 pounds in the conventional group.

At six months, weight loss averaged 15.2 pounds in the Atkins group and 6.9 pounds in the conventional group.

At one year, average weight loss was 9.5 pounds in the Atkins group and 5.4 pounds in the conventional group, a statistically insignificant difference, the study says.

A major concern about the Atkins diet has been that it might increase the risk of cardiovascular disease by raising blood levels of artery-clogging fats.

However, at the end of the year Atkins participants had an average 18 percent increase in HDL cholesterol - the "good" kind that helps clear arteries - compared to a 3 percent increase in the conventional group. And blood levels of artery-clogging triglycerides dropped 28 percent in the Atkins group, yet increased 1 percent in the conventional group.

A report in the same issue of the journal on a parallel study, conducted at Washington University in St. Louis, showed essentially similar results.

"We are happy that research is finally being done so that health-care providers can offer a safe alternative to those who want to follow a low-calorie diet," Heimowitz says.

Tailor Eating Plans for Individuals

Foster is much more cautious. "It looks like the diet merits further study and could help some people," he says. People now are being enrolled for a five-year study, he adds.

Yale's Katz says the studies were flawed because they were not "blind," meaning participants knew what their role was.

"If you know that you are testing something new, that is exciting, and it introduces a very important bias," Katz says.

Also, the dropout rate was very high - 43 percent in the conventional group, and 39 percent in the Atkins group. That could have skewed the results, he adds.

And the researchers never measured calorie intake, Katz points out.

Since the Atkins group participants were told to cut back on carbohydrates, "It is almost inevitable that they had lower calorie intake," he says. "Restricting choice is one of the most effective ways of reducing calorie intake."

Foster recommends that when an individual is considering a weight-loss plan, "Those decisions should be made on an individual level, with discussion between patient and doctor," Foster says.

Always consult your physician for more information.

 Online Resources

(Our Organization is not responsible for the content of Internet sites.)

American Thoracic Society

Centers for Disease Control and Prevention (CDC)

Centers for Medicare & Medicaid Services (CMS)

DASH Eating Plan, NHLBI

Eat Five to Nine A Day, National Cancer Institute (NCI)

National Heart, Lung, and Blood Institute (NHLBI)

National Institutes of Health (NIH)

For more information on health and wellness, please visit health information modules on this Web site.

Study Finds Emphysema Surgery Improves Lung Function

A five-year, multicenter study has found that, on average, patients who undergo bilateral lung volume reduction surgery (LVRS) to treat severe emphysema, in addition to medical therapy, are more likely to function better after two years compared to those who receive medical therapy only.

And, the study found, patients do not face an increased risk of death.

Emphysema is a progressive, chronic, and disabling lung condition that affects 2 million Americans, primarily individuals over age 50 who are current or former cigarette smokers.

Emphysema causes or contributes to 100,000 deaths in the US each year.

Emphysema is a condition in which alveoli, or air sacs, may be, destroyed, narrowed, collapsed, stretched, or over-inflated.

Over-inflation of the air-sacs is a result of a breakdown of the walls of the alveoli, and causes a decrease in respiratory function and breathlessness. Damage to the air sacs is irreversible and results in permanent "holes" in the tissues of the lower lungs.

Current medical treatments include smoking cessation for those who still smoke, exercise rehabilitation, oxygen therapy for those with low blood oxygen levels, medications such as bronchodilators to help open airways, and prompt treatment of respiratory infections.

Surgery Not for Everyone

In LVRS, 25 percent to 30 percent of the most damaged regions of each lung is surgically removed.

Experts believe that by surgically removing functionally useless tissue, air will move in and out of the remaining lung more readily, thereby easing symptoms associated with advanced emphysema and improving overall lung function.

The National Emphysema Treatment Trial (NETT), a randomized study, evaluated the effectiveness and safety of adding LVRS to medical therapy with pulmonary rehabilitation for patients with advanced emphysema.

Researchers found the effects of LVRS varied widely among patients, however.

They identified two qualities that helped predict the outcome of the surgery for individual patients: the distribution of emphysema - that is, whether the damage was concentrated in the upper areas of the lungs - and the patient’s exercise capacity.

Patients whose emphysema was mostly in the upper lobes of the lung, and whose exercise capacity was low after pulmonary rehabilitation but prior to surgery, were more likely to survive longer and function better after LVRS compared to similar patients who received medical therapy only.

The findings were presented at the American Thoracic Society 99th International Conference in Seattle, Wash. The results were posted on the New England Journal of Medicine (NEJM) Web site.

The study began in 1996 by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health (NIH), and the Centers for Medicare & Medicaid Services (CMS).

Increased Use of LVRS

“NETT was developed in response to concerns that lung volume reduction surgeries were becoming more common despite insufficient knowledge about the procedure’s safety and effectiveness,” said NHLBI Director Claude Lenfant.

“NETT provides the scientific evidence that establishes which patient characteristics are more accurate in predicting the surgical outcome,” noted Dr. Alfred P. Fishman, of the University of Pennsylvania, chair of the NETT steering committee.

“Perhaps most importantly, the NETT results identify who is at high risk for surgery,” added Fishman.

“Clearly, physicians and patients must weigh the risks of LVRS against the procedure’s potential for long-term benefits,” added Dr. Gail Weinmann, NHLBI project officer for NETT.

Always consult your physician for more information.