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Evid Based Nurs 10:111 doi:10.1136/ebn.10.4.111
  • Treatment

The Atkins diet led to more weight loss than the Zone diet in overweight and obese premenopausal women at 12 months


 
 Q What is the relative effectiveness of Atkins, Zone, “Lifestyle, Exercise, Attitudes, Relationships, and Nutrition (LEARN),” and Ornish diets for weight loss in overweight or obese premenopausal women?

METHODS

GraphicDesign:

randomised controlled trial (Atkins, Traditional, Ornish, Zone [A TO Z] Weight Loss Study).

GraphicAllocation:

unclear allocation concealment.

GraphicBlinding:

blinded {data collectors, data analysts, and safety and monitoring committee}.*

GraphicFollow-up period:

12 months.

GraphicSetting:

United States.

GraphicPatients:

311 premenopausal women 25–50 years of age (mean age 41 y, 71% white) who were overweight or obese (body mass index [BMI] 27–40 kg/m2), had stable weight in the past 2 months, and stable medications for ⩾3 months. Exclusion criteria included diabetes; hyperthyroidism; hypertension; heart, renal, or liver disease; cancer; use of drugs affecting weight or energy expenditure; ⩾3 drinks of alcohol/day; pregnancy; lactation; and amenorrhoea in the past year.

GraphicIntervention:

Atkins (very low carbohydrates [carbs]) (n = 77), Zone (low carbs) (n = 79), LEARN (low fat, high carbs) (n = 79), or Ornish (very high carbs) (n = 76) for 8 weeks. All women attended classes (1 h/wk for 8 wks) given by a registered dietician and received incentives for completing follow-up.

GraphicOutcomes:

weight loss. Secondary outcomes included concentrations of low-density lipoprotein cholesterol (LDLC), high-density lipoprotein cholesterol (HDLC), triglycerides, BMI, percentage of body fat, waist–hip ratio (WHR), and blood pressure (BP).

GraphicPatient follow-up:

80% (intention-to-treat analysis).

MAIN RESULTS

At 12 months, Atkins led to greater weight loss and decreases in systolic BP, BMI, and triglyceride concentrations than Zone, greater decreases in BP and higher HDLC concentrations than Ornish, and greater decreases in systolic BP than LEARN (table). The Zone, LEARN, and Ornish groups did not differ for any outcomes. Groups did not differ for body fat, WHR, or LDLC concentrations.

The Atkins v Zone, LEARN, and Ornish diets in overweight or obese premenopausal women*

CONCLUSION

The Atkins diet led to more weight loss than the Zone diet in overweight and obese premenopausal women at 12 months.

A modified version of this abstract also appears in Evidence-Based Medicine.

Commentary

  1. Kathryn Weaver, RN, PhD
  1. University of New Brunswick, Fredericton, New Brunswick, Canada

      Weight loss plans are essential tools for preventing and managing overweight and obesity. Although national dietary recommendations are based on several decades of research, many individuals experiment with alternative diets. This has important public health implications as participation in weight loss plans is costly, with limited effectiveness. Gardner et al report clinically significant weight loss of 2–5% for overweight or obese premenopausal women who followed diets ranging from severely restricted (Atkins), low (Zone), traditional (LEARN), to very high (Ornish) amounts of carbs for 1 year. Atkins, the most effective diet, led to a 4.7 kg loss and did not lead to any adverse events. Of 945 women who met eligibility criteria, only 311 participated. Given the lifestyle changes involved, those who participated may have been more motivated. Characteristics that may influence adherence, such as income, weight history, and prior knowledge of diets, were not explored, which may limit applicability of the results.

      As nurses advise patients on macronutrient composition, safety, and efficacy of various weight management choices, it is appealing to offer different types of diets. However, the finding that the Atkins diet led to greater weight loss and physiological benefits may not reassure nurses who have discouraged patients from this diet out of concern for cardiovascular risk, kidney impairment, cancer, bone mineral loss, and neurological symptoms.1 The follow-up period was not long enough to exclude long-term safety risks from deprivation of carbs and excess dietary protein and fat. It is also unclear whether weight loss can be sustained or whether the diet is palatable, satisfying, and affordable in the long term. Because of these limitations, nurses should counsel patients to follow national guidelines for consumption of carbs, protein, and fat.

      References

      Footnotes

      • * Information provided by author.

      • For correspondence: Dr C D Gardner, Stanford University Medical School, Stanford, CA, USA. cgardner{at}stanford.edu

      • Sources of funding: National Institutes of Health, Community Foundation of Southeastern Michigan, Human Health Services.

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