Objective: This study assessed whether a 5% to 10% reduction in initial weight would be associated with as favorable long-term (i.e., 100 weeks) changes in lipids and lipoproteins, as have been observed on a short-term basis (i.e., 8 weeks).

Research methods and procedures: This was a prospective evaluation of 25 obese women, each of whom had lost > or =5% of initial weight during 48 weeks of treatment and had maintained a weight loss of this magnitude at 1-year follow-up (week 100). Lipids and lipoproteins were obtained at baseline and at weeks 8, 24, 48, and 100. All participants had a baseline total cholesterol > or =5.17 mmol/L (200 mg/dL).

Results: At the end of the first 8 weeks, weight fell an average of 11.7+/-2.8%, total cholesterol 20.6+/-7.5%, low-density-lipoprotein (LDL) cholesterol 23.0+/-18.1%, and triglycerides 26.0+/-20.1%. At week 48, weight had fallen to 20.1+/-7.0% below baseline, but total cholesterol and LDL cholesterol were reduced only 11.5+/-10.4% and 12.0+/-14.0% below baseline, respectively. These latter reductions were significantly (p<0.05) smaller than those observed at week 8, despite the larger weight loss at week 48. High-density-lipoprotein cholesterol declined significantly (p<0.05) during the first 8 weeks, but returned to baseline values by week 24. Patients gained 7.4+/-7.4 kg from weeks 48 to 100, during which time total and LDL cholesterol (but not triglycerides) rose significantly (p<0.05). Patients who, at week 100, maintained losses >10% of initial weight had significantly greater reductions in total and LDL cholesterol values than did patients who maintained losses of only 5% to 10% of initial weight.

Discussion: Results of this study underscore the importance of assessing long-term changes in weight-related health complications when patients have lost weight but are no longer dieting (and exercising) as aggressively as they did during the initial months of treatment.