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

Metabolic Consequences of High and Low Carbohydrate Diets

This study will examine the effects of a low carbohydrate diet versus a high carbohydrate diet on weight loss.

Study Overview

• Status: Completed
• Conditions: Hypertension; Obesity
• Intervention / Treatment: Behavioral: Atkins diet (low carbohydrate diet); 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.

• Study Type: Interventional
• Enrollment (Actual): 260
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • Oregon
    • Portland, Oregon, United States, 97227
      • Kaiser Permanente Center for Health Research

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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: http://www.nhlbi.nih.gov/health/public/heart/hbp/dash/new_dash.pdf	Behavioral: DASH diet (high carbohydrate diet)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Weight loss	Excess weight loss (greater than 5 pounds a week)would trigger patient assessment.	monthly

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Risk of cardiovascular disease	Elevated lipids or rising blood pressure during six month safety assessments would trigger additional participant evaluation	Every six months
bone health		end of study
kidney function		every six months
neuroendocrine mechanisms of hunger and satiety		end of study

Collaborators and Investigators

• Sponsor: Kaiser Permanente
• Collaborators: National Center for Complementary and Integrative Health (NCCIH)
• Investigators: Principal Investigator: Njeri Karanja, PhD, Kaiser Permanente

Study record dates

Study Major Dates

• Study Start: April 1, 2005
• Primary Completion (Actual): March 1, 2009
• Study Completion (Actual): June 1, 2010

Study Registration Dates

• First Submitted: September 12, 2005
• First Submitted That Met QC Criteria: September 12, 2005
• First Posted (Estimate): September 20, 2005

Study Record Updates

• Last Update Posted (Estimate): December 6, 2012
• Last Update Submitted That Met QC Criteria: December 4, 2012
• Last Verified: February 1, 2008

More Information

Terms related to this study

• Keywords: Weight Loss; Diet; Carbohydrates
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Body Weight; Body Weight Changes; Hypertension; Weight Loss
• Other Study ID Numbers: R21AT000525-01 (U.S. NIH Grant/Contract); 1R01AT001930 (U.S. NIH Grant/Contract)