Nutritional applications of a clinical low fat dietary intervention to public health change

Abstract

There have been many recommendations to reduce dietary fat consumption, yet little research has focused on how individuals actually change their fat consumption. The Women's Health Trial (WHT) was successful in dramatically reducing the fat intake of women. It was designed as a multicentered trial to evaluate whether a low fat diet could reduce the incidence of breast cancer. This paper reports the results of nutritional endpoints: the methods used by the women to modify their diets, and the patterns of change that distinguished consistently good performers. Three hundred and three women were recruited through a series of screening visits and randomized to either intervention or control conditions. Intervention women received a fat gram goal of 20% of calories from fat and 20 dietary behavior change sessions. Fat consumption was assessed using weighed four-day food records at baseline and 3, 6, 12 and 24 month follow-up visits. Seventy-seven percent of the subjects in the WHT reduced their fat intakes from a mean of 39% of calories to 20% by six months. Over two-thirds of all subjects were maintaining that level two years later. The most and least successful performers made similar proportionate changes in fats from four food groups (fats/oils, red meats, dairy, and grain products). The major differences among the women were in the extent of the cuts made in the fat contributed from each food group and in long-term maintenance of the reductions. Specifically, the more successful women had less difficulty in making substantial reductions in the fat contributed by the fats/oils, red meat and dairy food groups. During maintenance, there was some minimal backsliding in the fats/oils group, but the initial reductions in the red meat and dairy groups were sustained. All the women appeared to have equal difficulty increasing their food intake from the complex carbohydrate food groups (fruits, vegetables, and grain products). These data have implications for the design of public health interventions to lower dietary fat.