Project Impact: An Innovative Approach to Weight Loss Maintenance

The major goal of this project is to evaluate an innovative approach to obesity. This study will determine if behavioral treatment can be improved by 1) implementing a primary focus on PA following initial weight loss treatment, and 2) using a novel, acceptance-based approach to the promotion of PA.

Most adults who engage in lifestyle modification find it difficult to maintain a high level of PA over the long-term, and most also find that weight regain is inevitable. The current portfolio of available interventions does not adequately address these challenges. This project is designed to test the effectiveness of an intervention that is specifically designed to enhance the ability to maintain, in the long-term, a level of PA high enough to achieve long-term weight loss maintenance. In the study, 300 obese adults will be recruited from the community and provided with 6 months of group-based, standard behavioral treatment for induction of weight loss (Phase I). A 6-month Phase I was chosen so that all participants will have sufficient time to accomplish initial weight loss before Phase II begins, allowing Phase II to truly be a test of weight loss maintenance. In Phase II, participants will receive one of three interventions, to be delivered for an additional 12 months: 1) behavioral treatment, with the standard emphasis on maintaining changes in diet and PA (BT), 2) behavioral treatment, with a primary emphasis on using these skills to maintain PA (BT-PA), or 3) acceptance-based behavioral treatment, with a primary emphasis on using these skills to maintain PA (ABT-PA). Assessments will be conducted at baseline, 6 months, 18 months (end of treatment), 24 months (6-month follow-up), and 36 months (18-month follow-up).

Eighteen months of standard, group-based behavioral treatment for weight loss and weight loss maintenance.

Six months of standard, group-based behavioral treatment for weight loss and weight loss maintenance, followed by 12 months of standard, group-based behavioral treatment for weight loss and weight loss maintenance with a larger emphasis on physical activity goals.

Six months of standard, group-based behavioral treatment for weight loss and weight loss maintenance, followed by 12 months of group-based behavior therapy with acceptance-based strategies, and a larger emphasis on physical activity goals.

Group- based behavioral treatment for weight loss and weight loss maintenance, with a standard emphasis on diet (65% of session) and physical activity goals (25% of session). Other weight loss behaviors such as self monitoring will be covered in the remaining time (10% of session).

Group-based behavioral treatment for weight loss and weight loss maintenance, with a larger emphasis on physical activity goals (65% of session) than eating-related goals (25% of session).Other weight loss behaviors such as self monitoring will be covered in the remaining time (10% of session).

Group-based, acceptance-based behavioral treatment for weight loss and weight loss maintenance, with a larger emphasis on physical activity goals (65% of session) than eating-related goals (25% of session).Other weight loss behaviors such as self monitoring will be covered in the remaining time (10% of session).

Time taken to complete a half-mile walk on the treadmill. Shorter times indicate a greater level of cardiorespiratory fitness.

Emotional Overeating Questionnaire. The Emotional Overeating Questionnaire is a six-item self-report questionnaire designed to assess the frequency of emotional overeating (Masheb & Grilo, 2006). Participants rate their frequency of eating an "unusually large amount" over the prior 28 days in response to 6 emotions (anxiety, sadness, loneliness, tiredness, anger, and happiness) on a 7-point Likert scale: 0 = no days, 1 =1-5 days, 2 = 6-12 days, 3 = 13-15 days, 4 = 16-22 days, 5 = 23-27 days, and 6 = every day. Responses to the six items are averaged for a total score. Total scores range from 0-6 (units are scores on the scale). Higher total scores indicate more frequent emotional overeating (i.e., worse outcome). The Emotional Overeating Questionnaire has previously shown high internal consistency (alpha = 0.85) with test-retest reliability among individuals with Binge Eating Disorder (Masheb & Grilo, 2006).

The 18-item Three Factor Eating Questionnaire (TFEQ) (Cappelleri, Bushmakin, Gerber, Leidy, Sexton, Lowe, et al., 2009) assessed disinhibited eating behavior. The questionnaire consists of statements about food and participants rate if they apply to them on a 4-point Likert scale (definitely true, mostly true, mostly false, definitely false). The questionnaire has a well-validated three-factor structure (Cronbach's α of 0.78-0.94), which includes a domain for disinhibited eating. This project used scoring from Niemeier, Phelan, Fava, & Wing, 2007, responses are coded 0 (mostly/definitely false) or 1 (mostly/definitely true). Total scores range from 0-18 (higher scores mean more problematic eating behaviors, i.e., worse outcome). The disinhibited eating subscale is the sum of 16 items (range 0-16), such as: "Sometimes when I start eating, I just can't seem to stop." Higher scores indicate higher levels of disinhibited eating (i.e., worse outcome). Units are scores on the scale.

The Power of Food Scale is a 15-item self-report questionnaire that assesses the tendency to eat for pleasure (rather than physiological hunger) based on cues from the environment (Lowe et al., 2009). Items measure participants' appetite-related thoughts, feelings, and motivations for highly palatable foods with three subscales based on food proximity: (1) Food available in the environment but not physically present (sum of 6 items, range 6-30) (2) Food physically present but not yet tasted (sum of 4 items, range 4-20), and (3) Food tasted but not yet consumed (sum of 5 items, range 5-25). An example item is: "If I see or smell a food I like, I get a powerful urge to have some." Participants rated each of these statements on a 5-point Likert scale from 1 (strongly disagree) to 5 (strongly agree). Total scores are a sum of the 15 items (range 15-75) (units are scores on the scale). Higher total and subscale scores indicate greater hedonic hunger (i.e., worse outcome).

Perceived Appetitive Response to Exercise. This was a single item measure, where participants were asked to select which one of these four options best described their experience in the past month: There is no relationship between my level of exercise and my appetite; Exercise helps me control my appetite - I am less hungry when I am exercising regularly; Exercise increases my appetite - I am more hungry when I am exercising regularly; Not applicable because not exercising. This item was constructed by the research team, as no pre-existing measure of this construct was identified. The count and percent of participants within each category (by treatment condition) was calculated. This variable consists of four categorical responses, and thus does not have a minimum/maximum value. None of the response options are considered better or worse than the others. Each option describes separate potential experiences participants may have had in relation to eating/exercise over the past month.

Inclusion Criteria: Have a BMI between 27 and 45 kg/m2 Have the ability to engage in at least 15 minutes of moderate physical activity (e.g. brisk walking) Successfully complete all steps in the enrollment process, including attendance at all pre-randomization clinic visits and providing physician clearance Exclusion Criteria: Have a medical condition that prevents safe engagement in moderate-to-vigorous physical activity Are lactating, pregnant, or planning to become pregnant in the next three years Report recently beginning a course of or changing the dosage of prescription medications that can cause significant weight loss or weight gain Are participating in or plan to participate in another weight loss program in the next three years Have a primary family member or member of their household participating in the study

Butryn ML, Crane NT, Lufburrow E, Hagerman CJ, Forman EM, Zhang F. The Role of Physical Activity in Long-term Weight Loss: 36-month Results From a Randomized Controlled Trial. Ann Behav Med. 2023 Feb 4;57(2):146-154. doi: 10.1093/abm/kaac028.

Butryn ML, Godfrey KM, Call CC, Forman EM, Zhang F, Volpe SL. Promotion of physical activity during weight loss maintenance: A randomized controlled trial. Health Psychol. 2021 Mar;40(3):178-187. doi: 10.1037/hea0001043.

Butryn ML, Martinelli MK, Remmert JE, Roberts SR, Zhang F, Forman EM, Manasse SM. Executive Functioning as a Predictor of Weight Loss and Physical Activity Outcomes. Ann Behav Med. 2019 Aug 29;53(10):909-917. doi: 10.1093/abm/kaz001.

Rosenbaum DL, Clark MH, Convertino AD, Call CC, Forman EM, Butryn ML. Examination of Nutrition Literacy and Quality of Self-monitoring in Behavioral Weight Loss. Ann Behav Med. 2018 Aug 16;52(9):809-816. doi: 10.1093/abm/kax052.