ABSTRACT
OBJECTIVE: A previously published randomized trial with individuals reporting high internal disinhibition showed significant differences in post-treatment weight change favoring Acceptance-Based Behavioral Intervention (ABBI) when compared to standard behavioral treatment (SBT). This paper examines process variables that might contribute to the observed differences in weight change. METHODS: Participants were 162 adults with overweight or obesity (mean BMI 37.6) randomly assigned to ABBI or SBT. Both interventions provided the same calorie intake target, exercise goal, and self-monitoring skills training. SBT incorporated current best practice interventions for addressing problematic thoughts and emotions. ABBI utilized acceptance-based techniques based on Acceptance and Commitment Therapy. ABBI and SBT were compared on process measures hypothesized to be related to outcome in ABBI and SBT and their association with weight loss outcomes using linear and non-linear mixed models methods and exploratory correlational analyses. RESULTS: Both the SBT and the ABBI groups showed significant changes over time on all process variables. The only significant between group difference was for values consistent behavior, with the ABBI group improving more as compared to SBT (t=2.45, p=.016); however, changes in values consistent behavior did not mediate weight change. Exploratory analyses suggest the possibility that changes in process variables were less associated with weight change in ABBI than in SBT after treatment was discontinued. CONCLUSIONS: Both conditions produced significant changes in process variables, however there was little difference between groups. Thus, the results do not provide an adequate process account for the observed weight change differences between ABBI and SBT, leaving important questions that need to be addressed by future research.
ABSTRACT
OBJECTIVE: Adults with overweight/obesity reporting high levels of internal disinhibition (ID) tend to do poorly in standard behavioural weight loss programmes. The current study sought to compare a sample of individuals with overweight/obesity selected on the basis of high ID with an unselected treatment-seeking sample of adults with overweight/obesity on characteristics that might make acceptance-based treatments particularly appropriate for those with high ID. METHODS: Sample 1 included 162 treatment-seeking adults with overweight/obesity who were selected for high ID; sample 2 included 194 unselected treatment-seeking adults with overweight/obesity. First, the two samples were compared on levels of general and weight-related experiential avoidance, and values-consistent behaviour, both of which are targeted in acceptance-based treatments, and on other general psychological characteristics. Next, the unselected sample was split into two groups, those meeting criteria for high (N = 105; sample 2/high ID) vs. low (N = 89; sample 2/low ID) ID, and the three groups were compared on the same characteristics. RESULTS: Sample 1 reported higher levels of both general and weight-related experiential avoidance as well as less values-consistent behaviour than sample 2. They reported greater psychological impairment in quality of life, depression and anxiety. Within sample 2, 54% met the criteria for high ID. Both sample 1 and sample 2/high ID reported higher levels of experiential avoidance and less values-consistent behaviour than did the sample 2/low ID. The two high ID samples also reported greater psychological impairment in quality of life, depression and anxiety than sample 2/low ID. CONCLUSIONS: Adults with overweight/obesity who report high levels of ID were characterized by higher levels of experiential avoidance, lower levels of values-consistent behaviour, and more psychosocial impairment as compared with other adults with overweight/obesity. As these are important targets of acceptance-based approaches, this subgroup may benefit from the integration of such approaches into behavioural weight loss programmes.
