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What's New - New Diet Grant

Study may solve the low-carb/high-carb diet controversy

Kaiser Permanente's Center for Health Research receives $3.3 million to enroll 240 local residents in study comparing safety and effectiveness of Atkins-style and DASH diets

(PORTLAND, Ore.) -  January 18, 2005 - To resolve a controversy whether a low-carbohydrate or a high-carbohydrate diet is better for one's health, the National Center for Complementary and Alternative Medicine - a branch of the National Institutes of Health - has awarded a $3,283,000 grant to Kaiser Permanente's Center for Health Research (CHR). With the grant, CHR researchers will conduct a five-year study to compare the safety and effectiveness of a low-carbohydrate Atkins-style diet with the more conventional high-carbohydrate DASH diet. Researchers at Oregon Health & Science University (OHSU) will collaborate with CHR researchers on this study.

 Low-carbohydrate, high-fat diets, such as the Atkins and South Beach diets, have become immensely popular among Americans who are trying to lose weight. Authors of books about these diets claim they result in rapid weight loss and improved disease risk without hunger and any need to pay attention to energy consumption. They also claim that more conventional high-carbohydrate, low-fat diets (such as the DASH diet) are responsible for our obesity epidemic. On the other hand, detractors of the low-carbohydrate, high-fat diets argue that such diets increase the risk of heart disease, diabetes and other chronic diseases, and do not lead to long-term weight loss.

"At this point, there are no valid scientific data either to support or refute claims on both sides of the debate," says Njeri Karanja, PhD, principal investigator for the study at CHR. "Several recent studies suggest that people lose more weight eating a low-carb, high-fat diet and that they had lower levels of triglyceride and higher levels of HDL, the so-called good cholesterol. The problem is that these studies have been short term, lasting either six months or a year at most. This is simply not enough time to answer questions about safety and effectiveness. Our new study will rectify this situation by comparing a low-carbohydrate, high-fat diet and a more conventional weight loss diet for 30 months in a randomized clinical trial. Our goal is to find out which diet better promotes both short-term and long-term weight loss, and which reduces or increases risk of cardiovascular and other chronic diseases. What we find will help clinicians and nutritionists give evidence-based advice to patients and help the general public make informed choices."

"Very low carbohydrate diets are diets that are extremely high in fat and protein and are especially low in fruits and vegetables," explained William Connor, M.D., professor of medicine (endocrinology, diabetes and clinical nutrition) in the OHSU School of Medicine. "An initial view of such diets is that they may be unhealthy, but since obesity is such a rampant problem in the American culture, it may be that the low-carbohydrate diets may still play a role in the treatment of obese patients. It is especially important to document what the long-term effects are, and these diets are largely unknown. Kaiser Permanente's Center for Health Research is particularly qualified to carry out long-term studies and to keep the patients in the study. What is notorious is the extremely high drop-out rate reported by all studies of diets in the treatment of obesity--drop out rates that sometimes exceed 40 percent of those initially enrolled. Questions about safety of the very low carbohydrate diets will be answered by the Kaiser Permanente study. I strongly support it and will cooperate in every way possible to bring it to a successful conclusion."

Two hundred and forty overweight or obese people will be recruited for the study, randomized either to the Atkins-style diet or the more conventional DASH diet, receive an intensive six-month behavioral intervention to lose weight, and then receive long-term counseling to maintain weight loss for the next two years. Because minority populations are disproportionately affected by obesity and its associated diseases, the study will recruit 20 percent of the participants from racial and ethnic minorities. Primary outcomes at 30 months will be changes in weight and markers for cardiovascular disease. Other outcomes will include changes in body composition, energy metabolism, as well as metabolism of lipids, lipoproteins, and carbohydrates.

How to join the study

Individuals who are interested in joining the study can call 503-528-3917 or send an e-mail (insight@kpchr.org) for more information about the study and the criteria for joining. Because there are potential safety issues with eating low-carb, high-fat diets, there is an extensive list of criteria for eligibility. However, there are a few major criteria people should know. To join the study, people must be at least 21 years of age, be overweight or obese (body mass index or BMI of 27-50), be able to modify their diet and other health behaviors, be willing to engage in regular exercise, be willing to be randomly assigned to either diet, and not be planning to move out of the area before the study ends. People who have diabetes or take cholesterol-lowering medications are not eligible to join this study.

Funding for this study is provided by the National Center for Complementary and Alternative Medicine (NCCAM) and by Kaiser Permanente Northwest's Community Benefit Program. NCCAM is providing $3,283,290 (97.15 percent of the total funding) and Kaiser Permanente Northwest is providing $100,000 (2.95 percent of the total funding).

Kaiser Permanente's Center for Health Research, founded in 1964, is a non-profit research institute whose mission is advancing knowledge to improve health. Kaiser Permanente Northwest is a prepaid group practice health care organization serving the medical needs of 445,000 people in Oregon and Southwest Washington.

OHSU includes the schools of dentistry, medicine, nursing and science and engineering; OHSU Hospital and Doernbecher Children's Hospital; numerous primary care and specialty clinics; multiple research institutes; and several outreach and community service units.

Released: January 18, 2005