Latent Profile Analysis of Physical Activity Motivation during Behavioral Weight Loss Treatment.

Participants in behavioral weight loss (BWL) treatment often struggle to meet and maintain physical activity (PA) prescriptions; improving participants' motivation for the behavior is a potential intervention strategy. Self-Determination Theory (SDT) outlines a continuum of qualitatively different dimensions of motivation, suggesting that more self-determined forms of motivation should predict more PA, whereas less self-determined forms of motivation should be unrelated or negatively related to PA. Although SDT has ample empirical support, most existing research in this area has used statistical analyses that oversimplify the complex, interdependent relationships between dimensions of motivation and behavior. This study's purpose was to explore commonly occurring motivational "profiles" for PA based on the SDT dimensions of motivation (amotivation, external, introjected, integrated/identified, and intrinsic motivation) and how these profiles relate to PA behavior among participants with overweight/obesity (N=281, 79.4% female) at baseline and six months into BWL treatment. Latent profile analysis determined that three motivational profiles fit the data best at both timepoints and the profile characterized by high self-determined (i.e., integrated/identified and intrinsic) motivation and moderate introjected motivation was by far the most common. There were no differences in physical activity behavior across motivational profiles, which contrasts previous literature. Findings suggest that participants who take the initiative to sign up for intensive BWL programs may have sufficiently high PA motivation, which may be a poor predictor of their actual behavior. Future research should examine these relationships later in treatment, when motivation may have more variability, as well as among participants who initiate lower-commitment weight loss programs (e.g., self-help).

Sharing digital self-monitoring data with others to enhance long-term weight loss: A randomized controlled trial.

BACKGROUND: Participants in behavioral weight loss (BWL) programs increasingly use digital tools to self-monitor weight, physical activity, and dietary intake. Data collected with these tools can be systematically shared with other parties in ways that might support behavior change. METHODS: Adults age 18 to 70 with overweight/obesity (BMI 27-50 kg/m2) will enroll in a remotely delivered, 24-month BWL program designed to produce and maintain a 10% weight loss. Participants will be asked to use a wireless body weight scale, wearable activity sensor, and dietary intake app daily. All participants will receive individual and group counseling, engage in text messaging with members of their group, and appoint a friend or family member to serve in a support role. A 2x2x2 factorial design will test the effects of three types of data sharing partnerships: 1) Coach Share: The behavioral coach will regularly view digital self-monitoring data and address data observations. 2) Group Share: Participants will view each other's self-monitoring data in small-group text messages. 3) Friend/Family Share: A friend or family member will view the participant's data via automated message. The primary outcome is weight loss at 24 months. Mediators and moderators of intervention effects will be tested. CONCLUSION: This study will provide a clear indication of whether data sharing can improve long-term weight loss. This study will be the first to discern the mechanisms of action through which each type of data sharing may be beneficial, and elucidate conditions under which the benefits of data sharing may be maximized.

Preliminary Free Energy Map of Prebiotic Compounds Formed from CO2, H2 and H2S.

What kinds of CHOS compounds might be formed in a prebiotic milieu by reducing CO2 in the presence of H2 and H2S? How might the presence of sulfur influence the chemical composition of the mixture? We explore these questions by using first-principles quantum chemistry to calculate the free energies of CHOS compounds in aqueous solution, by first generating a thermodynamic map of one- and two-carbon species. We find that while thiols are thermodynamically favored, thioesters, thioacids, and thiones are less favorable than their non-sulfur counterparts. We then focus on the key role played by mercaptoacetaldehyde in sulfur analogs of the autocatalytic formose reaction, whereby the thiol group introduces asymmetry and potential thermodynamic selectivity of some compounds over others.