Background.—Lack of response to a cholesterol-lowering diet can be caused by physiological nonresponsiveness, inadequate knowledge, or inability to change dietary habits (poor compliance). The purpose of this study was to evaluate the dietary compliance of hyperlipidemic individuals who received intensive initial dietary education and followup, and who showed an initial reduction of their plasma cholesterol levels. Methods.—One hundred five individuals with fasting cholesterol levels of 5.17 mmol/L (200 mg/dL) or greater received intensive education and follow-up on the American Heart Association Step I diet during an initial 12-week period. The participants provided 3-day dietary records every week, and fasting lipoprotein analysis was performed biweekly. Six months after termination of this period, the subjects were requested to return for a follow-up evaluation of their lipoprotein profile and dietary adherence. Results.—Seventy-three (70%) of the subjects returned for a follow-up evaluation of lipoprotein cholesterol levels. Of these, 42 (58%) had a 10% or greater average initial decrease in total cholesterol levels at weeks 3 and 4 (“baseline”), and they were considered to be “high responders.” At the 6-month follow up, the average plasma cholesterol level in these responders remained 6.4% below that at entry level, but it had increased by 19% compared with baseline values (6.30 mmol/L [244 mg/dL] vs 5.43 mmol/L [210 mg/dL], respectively). Corresponding significant increases at 6 months were found in high-density lipoprotein cholesterol (8%), low-density lipoprotein cholesterol (16%), and very-low-density lipoprotein cholesterol (66%) levels. Analysis of dietary histories revealed that dietary cholesterol and percent calories from fat increased significantly, but remained within the recommended guidelines. However, the increase in percent calories from saturated fat (from 10.0%±0.5% to 14.4%±1.0% [mean ± SEM]) deviated markedly from these guidelines. Conclusions.—The results suggest the long-term compliance to the reduction of dietary saturated fat remains a problem, even in individuals who receive intensive initial training and show an early favorable response. Follow-up evaluation of hyperlipidemic patients who are receiving dietary therapy should take into account this behavioral pattern. It remains to be determined whether continuing supervision and better nutritional labeling will facilitate dietary compliance. © 1992, American Medical Association. All rights reserved.