The Effect of Weight Loss Program on Overweight and Obese Females Based on Protection Motivation Theory: A Randomized Control Trial

It is especially true that prevalence of overweight and obesity is increasing worldwide and it is probably because of changes in diet and physical behavior pattern. The current study aimed to test the effect of weight loss program on overweight and obese females based on protection motivation theory. A randomized clinical trial (RCT) was implemented in the form of single blind. In total, 150 females with overweight and obesity were randomly divided into three groups including: 1, standard program group; 2, motivation interviewing (MI) group and; 3, motivation interviewing (MI) and intention intervention (II) condition (50 subjects in each group). They participated in a randomized clinical trial, also attended a private nutrition clinic in Gorgan city (Golestan province, North of Iran) for the first time. A researcher-made questionnaire and participant’s sheets (including three days food recall and anthropometric traits) were used to collect data. Data were analyzed using SPSS (ver.11) and statistical tests including Kruskal-Wallis, One-way ANOVA, Friedman test, Tukey test, Paired T-test and linear regression model were employed. The mean age of females was 38.45 ± 9.49 years, most of them had academic degree 46.7% (n = 70), 78.7% (n = 118) were married and 60.7% (n = 91) were housewives. ANOVA repeated measure test showed that daily energy intake decreased two (P = 0.001) and six months (P = 0.001), weight (P = 0.007) and body mass index (BMI) (0.005) after intervention. Threat appraisal statistically differed six months after intervention (P = 0.001). Motivational interviewing resulted in decreased daily energy intake, anthropometric characteristics as well as augmented scores of coping and threat appraisal.