A clinical trial to selectively change dietary pat and/or energy intake inwomen: The women's diet study

Dietary fat and energy intake have been implicated in breast cancer etiolog y. To examine the relative importance of these dietary factors on markers o f cancer risk in women, we designed an intervention trial to selectively de crease fat and/or energy intake in free-living, premenopausal women who wer e somewhat overweight. The study used a 2 x 2 factorial design to evaluate the independent and interactive effects of dietary far and energy. The diet s were nonintervention low fat (15% of energy from fat, maintenance of ener gy intake), low energy (25% energy reduction), and combination low fat and low energy. We utilized an individualized counseling approach with self-sel ection of foods. Women on the low-fat and combination diets were asked to m eet given daily goals for fat grams and food group exchanges, while rr,omen on the low-energy diet used only food group exchanges. Of the 113 premenop ausal women randomized who were eligible for analysis, 43% were Afri can-Am erican. A total of 88 women completed the 12-week program, and adherence to the dietary goals was similar in both racial groups. Women on the low-fat diet were able to reduce dietary far intake to 19% of energy by 4 weeks and to 17% by 12 weeks with a slight decrease in energy intake. Women on the l ow-energy diet met their energy reduction goals by four weeks while maintai ning percentage of energy from fat. Women on the combination diet largely m et their goals by four weeks as well. These data indicate that it is possib le to selectively manipulate dietary fat and energy intake in women over a short period of time, which makes clinical studies on the relative effects of these two dietary variables on cancer risk biomarkers readily feasible.