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The Safety and Effectiveness of Low and High Carbohydrate Diets

This study has been completed.
National Center for Complementary and Integrative Health (NCCIH)
Office of Dietary Supplements (ODS)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
Temple University Identifier:
First received: March 9, 2004
Last updated: June 28, 2013
Last verified: January 2008
This study will compare the safety and the effectiveness of a low carbohydrate diet (Atkins diet) with a high carbohydrate diet (conventional USDA diet).

Condition Intervention Phase
Behavioral: Low-calorie diet
Behavioral: low-carbohydrate diet
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: The Safety and Efficacy of Low and High Carbohydrate Diets

Further study details as provided by Temple University:

Primary Outcome Measures:
  • weight change [ Time Frame: 2 years ]

Secondary Outcome Measures:
  • change in lipids [ Time Frame: 2 years ]
  • blood pressure change [ Time Frame: 2 years ]
  • Ketones [ Time Frame: 2 years ]
  • Endothelial Function [ Time Frame: 2 ]
  • change in exercise endurance [ Time Frame: 2 years ]
  • change in renal function [ Time Frame: 2 years ]
  • change in bone density [ Time Frame: 2 years ]
  • change in body composition [ Time Frame: 2 years ]

Enrollment: 307
Study Start Date: April 2003
Study Completion Date: March 2008
Primary Completion Date: March 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 1
Low-calorie diet
Behavioral: Low-calorie diet
low-calorie diet
Experimental: 2
Low-carbohydrate diet
Behavioral: low-carbohydrate diet
low-carbohydrate diet

Detailed Description:

Despite the considerable mass appeal of popular diet books, such diet approaches lack data to support their efficacy and safety. Despite its widespread use for more than 30 years, the Atkins diet has never been evaluated in a large, randomized, controlled trial. This study will assess the short-term and long-term clinical effects of a low-carbohydrate diet and a high-carbohydrate diet in overweight and obese men and women.

Participants in this study will be randomly assigned to the Atkins diet (low-carbohydrate, unlimited fat and protein) or a conventional USDA diet (high-carbohydrate, low-fat). The study will evaluate the effects of each dietary approach on changes in: 1) weight and body composition; 2) metabolic and organ function; and 3) exercise tolerance. Each participant will be enrolled in the study for 2 years.


Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria

  • Body mass index between 30 and 40
  • Live and work within 1 hour of the study site
  • Stable psychological status

Exclusion criteria

  • History of heart disease, heart attack, or stroke
  • Blood pressure >140/90 mmHg
  • Abnormal cholesterol levels
  • Significant psychiatric illness
  • Any medication that affects weight or metabolic rate
  • Presence or history of a chronic disease that is known to affect appetite, food intake, or metabolism (i.e., diabetes, thyroid disease, or cancer)
  • Currently using antidepressants, steroids, tobacco, or illegal drugs
  • Pregnant, breastfeeding, or planning pregnancy
  • 10 lb change in weight within 6 months of study entry
  • History of malignant arrhythmias or cerebrovascular, renal, or hepatic disease
  • History of protein wasting diseases or gout
  • Severe arthritis
  • Osteoporosis
  • Certain types of hormone replacement therapy
  • Currently following a vegetarian diet
  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: NCT00079547

United States, Colorado
University of Colorado
Denver, Colorado, United States, 80262
United States, Missouri
Washington University
St. Louis, Missouri, United States, 63110
United States, Pennsylvania
University of Pennsylvania
Philadelphia, Pennsylvania, United States, 19104
Sponsors and Collaborators
Temple University
National Center for Complementary and Integrative Health (NCCIH)
Office of Dietary Supplements (ODS)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
National Heart, Lung, and Blood Institute (NHLBI)
Principal Investigator: Gary D Foster, PhD University of Pennsylvania
Principal Investigator: Holly Wyatt, MD University of Colorado, Denver
Principal Investigator: James Hill, PhD University of Colorado, Denver
Principal Investigator: Samuel Klein, MD Washington University School of Medicine
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Temple University Identifier: NCT00079547     History of Changes
Other Study ID Numbers: R01AT001103-01 ( US NIH Grant/Contract Award Number )
Study First Received: March 9, 2004
Last Updated: June 28, 2013

Keywords provided by Temple University:
Weight Loss processed this record on May 24, 2017