Three-year weight change in successful weight losers who lost weight on a low-carbohydrate diet.

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 >or=30-lb weight loss and >or=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, 1,895 +/- 452 vs. 1,398 +/- 574); fewer calories in weekly physical activity (1,595 +/- 2,499 vs. 2,542 +/- 2,301); 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.