Browsing by Subject "Behavior change"

Background: Obesity is the number one health risk facing Americans. The obesity epidemic in America is attributed to physical inactivity, unhealthy food choices, and excessive food intake. Structured weight loss programs have been successful in initiating behavior change and weight loss; however, weight is almost always regained over time. The rate of weight gain is highest immediately after cessation of a structured weight loss program. Thus, effective interventions are needed that can successfully be used following a structured weight loss program to sustain weight loss and prevent weight relapse. Due to low cost, ubiquity, and ease of use, healthcare communicated through mobile technology, or "mHealth", may be able to serve as an effective medium to reach a large number of people to facilitate weight loss behaviors. Short message service (SMS), also known as text messaging, is easy to use, ubiquitous, affordable, and can target people directly where they are regardless of geographic location, socioeconomic status, or demographic factors. A review of the literature demonstrated limited information regarding message content, timing and frequency of message delivery and only 3 of 14 SMS-related interventions reviewed demonstrated a statistically significant effect on weight loss, diet or exercise. Additionally, information on how to integrate and leverage SMS as a health promotion tool for weight loss was also limited in the literature.

The Behavior Change Process model was used as a guide to understand how to develop an intervention to help people sustain recent weight loss. Furthermore, research suggests interventions that target and frame messages about how people reach goals in their life through either a prevention or promotion focus may be beneficial at motivating people to self-regulate and sustain recent behavioral changes. The goal of this study was to design an intervention that would help people stay in the continued response phase of the Behavior Change Process and help prevent weight relapse. Using the Behavior Change Process and regulatory focus theory, an intervention was developed that leveraged short message service (SMS) to deliver messages to people who have recently lost weight in attempt to help them sustain weight loss and prevent relapse.

Methods: First, a pilot study was conducted to inform the development of a SMS software application, the development of message content and the frequency and timing of message delivery. Second, an exploratory 3-arm mixed methods randomized controlled trial was conducted to test the feasibility, acceptability, perception of the usefulness, and efficacy of a weight loss sustaining mHealth SMS intervention among people with obesity. Participants (N=120) were randomized to a promotion message group, a prevention message group, or an attention-control general health message group. Participants completed baseline assessments, and reported their weight at 1 and 3 months post-baseline to assess efficacy of the intervention on sustaining weight loss. In addition, participants partook in a phone interview follow completion of the intervention to assess acceptability and usefulness.

Results: Participants found the message content and intervention acceptable and a majority perceived value in receiving messages via SMS that promote weight loss sustaining behaviors. Interview data implied that the intervention served as a reminder and daily cue to action. Participants were favorable towards receiving a daily reminder, which they noted helped them to stay focused, and in some cases to keep them motivated to continue losing weight. And a majority, 42 (91%) who participated in a telephone interview said that they preferred to get messages on their cell phone due to accessibility and convenience. A minimum of one message per day delivered at approximately 8:00 A.M. was deemed the optimal delivery time and frequency. This was particularly true for weight loss, which many participants reported as a daily struggle that begins every morning. With regards to sustaining weight loss, there was a statistical trend in sustained weight loss at months 1 and 3 in the promotion and prevention framed message groups compared to the control group in both the intent-to-treat and evaluable case analyses. Clinically, there was a significant decrease in mean weight of approximately 5 pounds at month 3 in the promotion and prevention groups compared to the control. Additionally, effect sizes indicated a large effect of the intervention on sustaining weight loss in the promotion and prevention groups relative to the control group.

Conclusion: Overall results showed that at the continued response phase of the behavioral change process, it was feasible to design an application to deliver promotion and prevention framed weight loss sustaining messages. In particular, prevention framed messages may have been more useful in helping participants sustain weight loss. Though there was less than 80% power to detect a statistically significant difference, the observed effect sizes in this study were significant and demonstrated a large effect of the promotion and prevention interventions on sustaining weight loss relative to control. Furthermore, there was a clinically significant increase in mean weight loss and in the number of people who sustained weight loss in the promotion and prevention intervention groups compared to control.

These findings may serve as a reference for future interventions designed to help people thwart relapse and transition from a state of sustaining recent weight loss behaviors to a state of maintenance. Technological tools such as this SMS intervention that are constructed and guided by evidence-based content and theoretical constructs show promise in helping people sustain healthy behaviors that can lead to improved health outcomes.

Self-monitoring of dietary intake is a valuable component of behavioral weight loss treatment but engagement in self-monitoring declines quickly, resulting in suboptimal treatment outcomes. This dissertation examined a novel weight loss intervention that aims to lessen the decline in self-monitoring engagement by building mastery, self-efficacy, and self-regulatory skills—key constructs of behavior change—prior to self-monitoring diet. GoalTracker was a randomized controlled trial among 105 adults with overweight or obesity comparing three standalone 12-week weight loss interventions: (1) a Simultaneous arm with concurrent self-monitoring of weight and diet each day, along with weekly lessons, action plans, and tailored feedback via email; (2) a Sequential arm with the same components but that tracked only weight through week 4, then added diet tracking; and (3) an App-Only arm that only tracked diet, and did not receive additional behavior change components. All groups used the commercial app MyFitnessPal for self-monitoring and received a tailored calorie goal and a goal to lose 5% of initial weight by 12 weeks. Paper one examined the impact of the intervention on weight change and self-monitoring engagement (Aims 1-3) and found significant weight loss and engagement for all treatment arms, with no differences between arms. Paper two examined the relation between consistent self-monitoring and weight loss (Aim 4), revealing that consistent trackers lost significantly more weight than others. Lastly, paper three examined whether early weight loss predicts future engagement and weight loss success (Aim 5), which was supported. Regardless of the order in which diet is tracked, using tailored goals and a commercial app can produce clinically significant weight loss. Consistent self-monitoring and early weight loss should be emphasized. Standalone digital health treatments may be a viable option for those looking for a lower intensity approach.

Physical activity has many benefits including promoting healthy aging, reducing risk of chronic disease, and supporting general well-being. Despite this, many adults do not get significant amounts of daily physical activity. The effects of interventions promoting physical activity are highly variable and typically modest. Even when behavioral interventions are effective, the understanding of how and why they work is lacking. Understanding the determinants of physical activity behavior change, along with identifying evidence-based behavior change techniques that target these determinants, is critical for developing effective interventions. In this dissertation, across two studies, I examine the role of neural and behavioral determinants of physical activity behavior change. Chapter 1 provides a review of the two prominent theoretical approaches to physical activity behavior change, social cognitive theory and dual-process theory, and highlights how neuroimaging techniques can be utilized to help inform gaps in both theoretical and applied knowledge of physical activity. Chapter 2 (Study 1) evaluates if there are brain regions correlated with physical activity behavior change. In the study, participants wore a pedometer for a week before and after an fMRI session where they read and heard statements about walking. Behavioral analysis demonstrated that participants walked significantly more following exposure to the walking-related messages. Whole-brain analysis examined regions positively associated with walking behavior change and produced two significant clusters in the frontal pole region and the precuneus/posterior cingulate gyrus region. The frontopolar cortex is implicated in pre-commitment, a self-control strategy where people anticipate self-control failures and prospectively restrict their access to tempting alternatives. The precuneus/posterior cingulate cortex region has been found to play a role in self-relevant processing. Both self-control and self-relevant processing are believed to be important for behavior change. Chapter 3 (Study 2) focuses on neural and self-report responses to different types of health messages and their ability to predict physical activity behavior change. In the study, participants completed an fMRI task where they read positively or negatively framed walking-related messages with either social or non-social based content and rated how personally motivating they were as well as other self-reported ratings. Neural activity in regions involved in positive valuation and self-referential processing were measured to evaluate whether sensitivity in these regions to individual messages could predict the effectiveness of those messages when delivered in an intervention weeks or months later. For the next 80 days, participants completed a SMS-based mHealth intervention where they received one of the same walking-related messages from the scanner task daily. We assessed physical activity using a wearable fitness tracker throughout the 80 days and a baseline period. Individual participant ratings on how relevant the message would be to others predicted the effectiveness of the messages. People were more physically active on days when they received messages that were rated as more relevant to others. Brain activation in the regions of interest selected were not associated with message effectiveness during the intervention.