1. ^*Department of Psychiatry and Behavioral Medicine, Brown Medical School/The Miriam Hospital, Providence, Rhode Island
2. ^†Division of Endocrinology, Metabolism and Diabetes, University of Colorado Health Sciences Center, Denver, Colorado
3. Center for Human Nutrition, University of Colorado Health Sciences Center, Denver, Colorado
4. ^‡Department of Anesthesia, Harvard University/Brigham and Women's Hospital, Boston, Massachusetts
5. ^§Department of Epidemiology, Brown University, Providence, Rhode Island
6. ^¶Centers for Behavioral and Preventive Medicine, and Weight Control and Diabetes Research Center, The Miriam Hospital, Providence, Rhode Island

Correspondence: Suzanne Phelan Department of Psychiatry and Behavioral Medicine, Brown Medical School, 196 Richmond Street, Providence, RI 02903. E-mail: sphelan@lifespan.org

^**The costs of publication of this article were defrayed, in part, by the payment of page charges. This article must, therefore, be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Received 2 November 2006; Accepted 13 February 2007.

Abstract

Objective: The purpose of this study was to evaluate long-term weight loss and eating and exercise behaviors of successful weight losers who lost weight using a low-carbohydrate diet.

Research Methods and Procedures: This study examined 3-year changes in weight, diet, and physical activity in 891 subjects (96 low-carbohydrate dieters and 795 others) who enrolled in the National Weight Control Registry between 1998 and 2001 and reported 30-lb weight loss and 1 year weight loss maintenance.

Results: Only 10.8% of participants reported losing weight after a low-carbohydrate diet. At entry into the study, low-carbohydrate diet users reported consuming more kcal/d (mean SD, 1895 452 vs. 1398 574); fewer calories in weekly physical activity (1595 2499 vs. 2542 2301); more calories from fat (64.0 7.9% vs. 30.9 13.1% ), saturated fat (23.8 4.1 vs. 10.5 5.2), monounsaturated fat (24.4 3.7 vs. 11.0 5.1), and polyunsaturated fat (8.6 2.7 vs. 5.5 2.9); and less dietary restraint (10.8 2.9 vs. 14.9 3.9) compared with other Registry members. These differences persisted over time. No differences in 3-year weight regain were observed between low-carbohydrate dieters and other Registry members in intent-to-treat analyses (7.0 7.1 vs. 5.7 8.7 kg).

Discussion: It is possible to achieve and maintain long-term weight loss using a low-carbohydrate diet. The long-term health effects of weight loss associated with a high-fat diet and low activity level merits further investigation.