Predictors of dietary change and weight loss in moderately obese elders

Abstract

This project was an outgrowth of the DIET study (Dornelas, Wylie-Rosett, & Swencionis, 1998; Goldman, Wylie-Rosett, Swencionis, & Dornelas, 1992; Wylie-Rosett et al., 1994), a comprehensive behavioral intervention program for dietary change and weight management. The purpose of the study was twofold: (1) to determine the long-term effectiveness of dietary fat reduction as a method for achieving and maintaining weight loss; and (2) to assess the role of dietary self-efficacy as a potential predictor of sustained reduced dietary fat intake.;Change in body weight was predicted to be positively related to change in fat intake from baseline to follow-up. Also predicted was an inverse relationship between change in fiber intake and body weight. It was hypothesized that high dietary self-efficacy measured at baseline would be associated with greater dietary fat reduction and weight loss.;Subjects were 77 moderately obese men and women (mean age 67 years). A food frequency questionnaire estimated macronutrient intake at baseline and follow-up. Dietary self-efficacy was assessed at baseline to predict dietary fat reduction at follow-up.;For most participants, the intervention resulted in significant declines in fat consumption (M = --10.7 g +/- 18.9 [--2.4 % kcal +/- 7.3], p < .005), caloric intake ( M = --175.2 kcal +/- 406.1, p < .001), and body weight (M = --7.4 lb +/- 9.7, p < .001) that were maintained for three years after the initiation of treatment. Weight change was not associated with fiber intake. Baseline weight and change in total fat intake (in grains) were the variables most predictive of weight change, supporting the hypothesis that alterations in dietary composition, particularly reduced fat consumption, may be a more powerful determinant of sustained weight loss when combined with a decrease in overall caloric intake. In addition, change in the amount of fat consumed (as a percentage of total calories) was found to be inversely related to baseline dietary self-efficacy for relapse resistance. This finding suggests that higher levels of confidence in one's ability to refrain from lapsing back into former dietary habits may predict success in reducing fat intake as a percentage of overall energy consumption.