Acceptance Based Behavioral Intervention for Weight Loss: A Randomized Trial

Obesity is a major health problem and behavioral weight control programs are the treatment
of choice for mild and moderate obesity. However, there is marked variability among
participants in the weight losses achieved in these programs and the maximum weight losses
are typically achieved at month 6, followed by weight regain. Thus innovative approaches are
needed to improve longer-term treatment outcomes.

Currently, the same behavioral treatment program is offered to all participants, with no
tailoring to meet the needs of specific subgroups. One subgroup that may need a specialized
approach are those who report high levels of internal disinhibition, i.e. eating in response
to negative thoughts or emotions. Over 50% of individuals entering behavioral weight loss
programs report high levels of internal disinhibition on the Eating Inventory (EI), this
subgroup is distinct from those with binge eating disorder, and most importantly, these
individuals lose significantly less weight than other participants during weight loss
treatment [particularly at 18 months]. Thus efforts are needed to develop more effective
treatments for this subgroup. The proposed research is significant because it may help move
the field from a "one size fits all" approach, to the development of interventions for
specific subgroups of the population.

The investigators hypothesize that individuals who report problems with internal
disinhibition may achieve better weight losses in an enhanced behavioral weight loss program
that focuses on acceptance-based strategies. Whereas standard behavioral treatments teach
patients to control their negative thoughts with techniques such as cognitive restructuring
and distraction, acceptance based strategies teach patients to experience thoughts and
feelings as they are, without attempting to control them and to continue to pursue their
behavioral goals despite experiencing negative thoughts and feelings. Acceptance-based
strategies have been shown to be helpful for a number of behavioral problems including
weight loss and maintenance, however are yet untested in large trials.

The current study is a randomized controlled trial comparing standard behavioral weight loss
treatment with a program which incorporates acceptance based strategies in the treatment of
overweight/obese individuals with problems with internal disinhibition. A total of 160
participants will be randomly assigned to a standard behavioral weight loss treatment
program (SBT) or to an innovative approach that combines standard behavioral weight loss
with acceptance based strategies (referred to hereafter as "Acceptance Based Behavioral
Intervention" or ABBI). Both groups will meet weekly for 6 months, biweekly for 3 months and
then monthly for 3 months. Assessments will be conducted at baseline and 6 month intervals
for 24 months total, with measures of weight, acceptance of negative emotions, distress
tolerance, and adherence to the weight loss program.

The primary hypothesis is that participants in the ABBI program will achieve greater changes
in weight (in the form of weight reductions) at 6, 12, 18, and 24 months when compared to
baseline weight than participants in SBT. Secondary hypotheses are that participants in ABBI
will experience greater improvements in acceptance of weight related negative thoughts and
emotions and distress tolerance and better treatment adherence than participants in SBT.

Inclusion Criteria:

- Must live in the greater Providence, RI area and be able to attend treatment sessions
on site for 1 year

- BMI between 30-50

- Age between 18-70

- meets clinical cutoff on Internal Disinhibition sub-scale of the Eating Inventory

Exclusion Criteria:

- report a heart condition, chest pain during periods of activity or rest, or loss of
consciousness

- physically unable to exercise

- are currently pregnant or plan to become pregnant in the next 24 months

- are planning to move outside the state within the next 24 months

- Cancer diagnoses in the past 5 years