Losing Weight from A to Z (Atkins to Zone Diets) in Women: Where is the Data?
Abstract & Commentary
By Joseph Varon, MD, FACP, FCCP, FCCM, Clinical Professor of Internal Medicine, University of Texas Health Science Center, Houston; Adjunct Professor of Medicine, University of Texas Medical Branch, Galveston. Dr. Varon reports no financial relationship to this field of study.
Synopsis: When compared to The Zone, Ornish, or LEARN diets, the very low carbohydrate diet (Atkins), showed that premenopausal, overweight, and obese women lost more weight and had the most beneficial metabolic effects at 12 months.
Source: Gardner CD, et al: JAMA. 2007;297:969-977.
This prospective, randomized clinical trial was designed to test whether any of 4 diets, representing a spectrum of carbohydrate intake, was more effective than any other in 12-month weight loss follow up. Outpatient premenopausal women aged 25 to 50 years were invited to enroll in this study through a media advertisement campaign if their body mass index was 27 to 40, their body weight had been stable over the prior 2 months, and medications were stable for at least 3 months. Women were excluded if they had hypertension (except for those whose blood pressure was stable using antihypertensives); diabetes mellitus; heart, renal, or active liver disease; malignancies, and hyperthyroidism unless treated and under control. Each diet group attended 1-hour classes once a week for 8 weeks. Close follow up as well as telephone and e-mail remainders for appointments were done. A specific target goal was given to each patient. Diet and physical activity data were collected as well as anthropometric values. Blood samples for lipids, total insulin levels and blood glucose were also collected.
Over the study period, 1479 individuals were screened. Of them 311 participated in the study and randomized to one of the four diets. Two hundred forty-nine participants completed the full 12-month protocol. In all groups 85-95% of participants attended the educational classes. Total energy expenditure was not different among the groups. The mean 12-month weight changes was -4.7 Kg for Atkins, -1.6 Kg for the Zone diet, -2.2 Kg for LEARN, and -2.6 Kg for the Ornish diet. At the 2 and 6 month time points, the weight change for the Atkins group was significantly greater than for all other groups. The lipid profile was improved among the Atkins group. A decrease in blood pressure was significantly greater in the Atkins group than for any other group.
Commentary
Obesity is a serious disorder resulting in significant impairment of health.1 Overweight and obese adults are at an increased risk of morbidity and mortality from many acute and chronic medical conditions, including hypertension, dyslipidemia, coronary heart disease, diabetes mellitus, gallbladder disease, respiratory disease, some types of cancer, gout, and arthritis. Furthermore, the incidence of obesity has increased in the United States since 1960 when the first obesity survey was conducted.2 The number of diet approaches to obesity has also increased exponentially.
This study is particularly interesting because it reveals that in a 12-month period, the Atkins diet was superior to other diets in premenopausal women. Moreover, the concerns that have been raised over the years regarding low-carbohydrate weight-loss diets such as adverse effects on lipids and blood pressure were not substantiated in this study.3 Based on the study by Gardner and coworkers, low carbohydrate diets are effective, in particular the Atkins diet, and the effects on lipids are unlikely to be of immediate concern.4 Long-term success, however, requires adherence to the nutritional regimen.
References:
1. Health Implications of Obesity: National Institutes of Health Consensus Development Conference Statement. Ann Intern Med. 1985;103:147-151.
2. Marik P, Varon J. Chest. 1998;113:492-498
3. Connor WE, Connor SL. N Engl J Med. 1997;337:562-563.
4. Gardner CD, et al. JAMA. 2007;297:969-977.
When compared to The Zone, Ornish, or LEARN diets, the very low carbohydrate diet (Atkins), showed that premenopausal, overweight, and obese women lost more weight and had the most beneficial metabolic effects at 12 months.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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