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Effectiveness of a Low Carbohydrate Diet Versus a High Carbohydrate Diet in Promoting Weight Loss and Improved Health

This study has been completed.
National Center for Complementary and Integrative Health (NCCIH)
Information provided by (Responsible Party):
Kaiser Permanente Identifier:
First received: September 12, 2005
Last updated: December 4, 2012
Last verified: February 2008
This study will examine the effects of a low carbohydrate diet versus a high carbohydrate diet on weight loss.

Condition Intervention Phase
Obesity Hypertension Behavioral: Atkins diet (low carbohydrate diet) Behavioral: DASH diet (high carbohydrate diet) Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Metabolic Consequences of High and Low Carbohydrate Diets

Resource links provided by NLM:

Further study details as provided by Kaiser Permanente:

Primary Outcome Measures:
  • Weight loss [ Time Frame: monthly ]
    Excess weight loss (greater than 5 pounds a week)would trigger patient assessment.

Secondary Outcome Measures:
  • Risk of cardiovascular disease [ Time Frame: Every six months ]
    Elevated lipids or rising blood pressure during six month safety assessments would trigger additional participant evaluation

  • bone health [ Time Frame: end of study ]
  • kidney function [ Time Frame: every six months ]
  • neuroendocrine mechanisms of hunger and satiety [ Time Frame: end of study ]

Enrollment: 260
Study Start Date: April 2005
Study Completion Date: June 2010
Primary Completion Date: March 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Atkins Diet
Participants randomized to this arm will consume a low carbohydrate diet as described by Dr. Robert Atkins in his book: Dr. Atkins' New Diet Revolution New York: Avon Books, 2002.
Behavioral: Atkins diet (low carbohydrate diet)
Active Comparator: DASH Diet
Participants randomized to this arm will consume the Dietary Approaches to Stop Hypertension (DASH) diet as described here:
Behavioral: DASH diet (high carbohydrate diet)

Detailed Description:

The number of overweight and obese Americans has increased significantly in recent years. There are now many different diet plans being promoted by doctors and the media. The Atkins diet, a low carbohydrate nutritional plan, is especially popular; its advocates claim that following the diet will result in long-term weight loss with no negative effects. Another diet, called the Dietary Approaches to Stop Hypertension (DASH) diet, is a high carbohydrate diet designed to help treat and prevent high blood pressure. However, more thorough investigation of these claims is needed. This study will compare the short- and long-term effects of the Atkins diet to the (DASH) diet. This trial will enroll overweight and obese participants.

This study will last 30 months and will comprise two phases. Participants will be randomly assigned to either the Atkins or DASH diet for 30 months. During Phase 1, all participants will undergo 6 months of weekly group therapy to encourage weight loss. Phase 2 is a weight loss maintenance phase. During Phase 2, participants will have monthly meetings with a therapist for weight loss support. Study visits will occur at study entry and at Months 3 and 30. At each study visit, weight measurements, blood and urine collection, and x-rays will occur to determine participants' weight loss, cardiovascular health, kidney function, and bone density.


Ages Eligible for Study:   21 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Body mass index (BMI) of 27 to 50
  • Fasting glucose less than 126 mg/dl
  • Total fasting cholesterol less than 260 mg/dl
  • Total fasting triglycerides less than 400 mg/dl
  • Permission of primary care provider to participate in the study
  • Normal liver and kidney function
  • Willing to modify diet and other health behaviors
  • Willing to use an acceptable method of contraception for the duration of the study

Exclusion Criteria:

  • Any medical condition that may make weight loss medically inadvisable
  • Weigh more than 400 lbs
  • History of kidney failure
  • Current use of more than 3 blood pressure medications
  • Change in blood pressure medications within 3 months prior to study entry
  • Diagnosis of cardiovascular disease within 6 months prior to study entry
  • Cancer diagnosis within 2 years of study entry. Participants with basal cell skin cancer are not excluded.
  • History of psychiatric hospitalization within 2 years prior to study entry
  • Consumption of more than three alcoholic drinks a day
  • Type I or II diabetes
  • Current use of hypolipidemics, antipsychotics, hypoglycemics, glucocorticoids, or thyroid medication
  • Plan to move during study
  • Current participation in another clinical trial
  • Pregnancy or breastfeeding
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00200720

United States, Oregon
Kaiser Permanente Center for Health Research
Portland, Oregon, United States, 97227
Sponsors and Collaborators
Kaiser Permanente
National Center for Complementary and Integrative Health (NCCIH)
Principal Investigator: Njeri Karanja, PhD Kaiser Permanente Northwest Center for Health Research
  More Information

Responsible Party: Kaiser Permanente Identifier: NCT00200720     History of Changes
Other Study ID Numbers: R21AT000525-01 ( U.S. NIH Grant/Contract )
1R01AT001930 ( U.S. NIH Grant/Contract )
Study First Received: September 12, 2005
Last Updated: December 4, 2012

Keywords provided by Kaiser Permanente:
Weight Loss processed this record on September 21, 2017