Comparing the Effectiveness of Cognitive Behavioral Therapy (CBT) and Acceptance Commitment Therapy (ACT) on Body Mass Index (BMI) and Character Strengths Among Overweight Women

 Obesity and overweight are among the most common health issues in the world related to physical problems. Psychological and biological factors are associated with overweight. So, any intervention for weight reduction should be based on psychological issues and diet. Different interventions for weight reduction have been studied before, but their effectiveness has been less compared. Improving a healthy lifestyle is an assumed mechanism of effectiveness in psychological interventions for weight reduction. Previous studies indicate that character strengths are related to healthy behavior, and six character strengths had the highest correlation with healthy behavior: authenticity, self–regulation, emotional intelligence, kindness, love, and vitality. So, it can be hypothesized that any psychological intervention developed to improve healthy behavior can also effectively improve the six mentioned character strengths. The present research compared the effectiveness of Cognitive Behavioral Therapy (CBT) and Acceptance Commitment Therapy (ACT) on Body Mass Index (BMI) and character strengths among overweight women.

 This quasi–experimental research employed a pretest–posttest and a three–month follow–up design with a control group. The study population consisted of all overweight women living in Mashhad City, Iran, in 2019. Forty–five overweight women were selected through convenience sampling and allocated to two experiment groups of CBT and ACT and one control group (n=15/group). The sample selection lasted one month according to the WHO definition of overweight and obesity. The inclusion criteria comprised the age range of 18–35 years, body mass index (BMI) more than 25 kg/m2 and signing the informed consent form before participating in the study. The exclusion criteria consisted of concurrent use of other psychological interventions and problematic mental or physical issues for weight reduction. All participants were examined in BMI and responded to Values in Action–Inventory of Strengths (Peterson & Seligman, 2004) and demographic questionnaire in pretest, posttest, and follow–up sessions. Both experimental groups received six sessions based on the weight scape program (Ciarochi et al., 2014) and Beck’s diet solution program (Beck, 2007). Descriptive statistics, including mean and standard deviation, describe the obtained data. To analyze the data, variance analysis, Chi–square test, analysis of variance with repeated measures, and LSD post hoc test at a significance level of 0.05 were used in SPSS version 23 software.

 Findings demonstrated that BMI in experimental groups was significantly lower than the control group (p<0.001). However, no difference was found between intervention groups in BMI (p=0.812). The scores of the variables of authenticity (p<0.001, p<0.001), kindness (p<0.001, p<0.001), and self–regulation (p=0.002, p<0.001) in the participants of the experimental groups, respectively, ACT and CBT were significantly more compared to the control group. In addition, the participants of the ACT group had higher scores compared to the CBT group in the variable of emotional intelligence (p=0.034) and had higher scores compared to the groups CBT and the control group in the love variable (p=0.007 and p<0.001, respectively).

 CBT and ACT have the same effectiveness in reducing body mass index. However, ACT cultivates a broader range of personality abilities and explicitly affects the personality ability of emotional intelligence and love.