Evaluation of a self-help dietary intervention in a primary care setting

Background. Dietary intervention to reduce fat consumption and increase fiber consumption has been recommended by the National Cancer Institute, but there is little evidence concerning the effectiveness of self-help materials. The purpose of this study was to evaluate such self-help materials, introduced by a nurse in a primary care setting. Methods. A randomized controlled trial involving 242 subjects was conducted in two primary care clinics in Chapel Hill, NC, in 1987. Changes in fat and fiber consumption in the intervention and control groups during the 3-month interval between interviews were compared using analysis of covariance. Results. The estimated reduction in fat was 3.8g larger for the intervention group than for the control group, but the confidence interval included zero. For those individuals who had some responsibility for meal preparation there was a larger difference (-6.9g) in favor of the intervention group, although the difference using calorie-adjusted values was -3.8g with a 95% confidence interval (-7.1, -0.4). The differences for fiber change were smaller. Conclusions. We found significant small but consistent differential changes associated with a minimal self-help intervention, but we cannot rule out the possibility of some response bias. Nonetheless, this study demonstrates that the use of self-help materials for dietary change is feasible, and may be effective.