This study was done to determine if significant weight loss, decrease in body measurements, and lowering of serum lipids and blood pressure could be shown in people on a low-calorie, low-fat, high-fiber diet over a period of six weeks. Forty-one people (33 females and 8 males) between the ages of of 37 and 55 years old participated in a six-week calorie-controlled, low-fat, low-sodium, high-fiber diet using foods available in supermarkets. Participants also exercised moderately. The average weight loss was 10.3 pounds, or 5.8% of the original average weight. The body mass index decreased 1.7-a 6.0% decrease for women and a 5.3% decrease for men. The average of five body measurements decreased 4.9%. Total cholesterol decreased 16%, LDL-C decreased 12%, and HDL-C decreased 18%. All of these decreases were statistically significant at P < .001. No significant difference was noted in blood pressures at the start and completion of the study, as both values were in the normal range. This relatively short period of dieting using 1200 calories for women and 1500 calories for men, along with moderate exercise, shows that reasonable weight loss and a tendency toward lowering lipid values can be obtained. Weekly monitoring by physicians and their office staffs can enhance this process. Continued accountability and support for lifelong behavior changes are probably necessary to maintain reasonable body weight in these patients.