a b s t r a c tBackground: Although there is substantial evidence of differential hypothalamic-pituitary-adrenal (HPA) axis activity in both generalized and abdominal obesity, consistent trends in obesity-related HPA axis perturbations have yet to be identified. Objectives: To systematically review the existing literature on HPA activity in obesity, identify possible explanations for inconsistencies in the literature, and suggest methodological improvements for future study. Data sources: Included papers used Pubmed, Google Scholar, and the University of California Library search engines with search terms body mass index (BMI), waist-to-hip ratio (WHR), waist circumference, sagittal diameter, abdominal versus peripheral body fat distribution, body fat percentage, DEXA, abdominal obesity, and cortisol with terms awakening response, slope, total daily output, reactivity, feedback sensitivity, long-term output, and 11␤-HSD expression. Study eligibility criteria: Empirical research papers were eligible provided that they included at least one type of obesity (general or abdominal), measured at least one relevant cortisol parameter, and a priori tested for a relationship between obesity and cortisol. Results: A general pattern of findings emerged where greater abdominal fat is associated with greater responsivity of the HPA axis, reflected in morning awakening and acute stress reactivity, but some studies did show underresponsiveness. When examined in adipocytes, there is a clear upregulation of cortisol output (due to greater expression of 11␤-HSD1), but in hepatic tissue this cortisol is downregulated. Overall obesity (BMI) appears to also be related to a hyperresponsive HPA axis in many but not all studies, such as when acute reactivity is examined. Limitations: The reviewed literature contains numerous inconsistencies and contradictions in research methodologies, sample characteristics, and results, which partially precluded the development of clear and reliable patterns of dysregulation in each investigated cortisol parameter. Conclusions and implications:The literature to date is inconclusive, which may well arise from differential effects of generalized obesity vs. abdominal obesity or from modulators such as sex, sex hormones, and chronic stress. While the relationship between obesity and adipocyte cortisol seems to be clear, further research is warranted to understand how adipocyte cortisol metabolism influences circulating cortisol levels and to establish consistent patterns of perturbations in adrenal cortisol activity in both generalized and abdominal obesity.

Relationship partners affect one another’s health outcomes through their health behaviors, yet how this occurs is not well understood. To fill this gap, we present the Dyadic Health Influence Model (DHIM). The DHIM identifies three routes through which a person (the agent) can impact the health beliefs and behavior of their partner (the target). An agent may (a) model health behaviors and shape the shared environment, (b) enact behaviors that promote their relationship, and/or (c) employ strategies to intentionally influence the target’s health behavior. A central premise of the DHIM is that agents act based on their beliefs about their partner’s health and their relationship. In turn, their actions have consequences not only for targets’ health behavior but also for their relationship. We review theoretical and empirical research that provides initial support for the routes and offer testable predictions at the intersection of health behavior change research and relationship science.

Over 2 decades ago, social psychological research revealed that weight stigma may undermine educational achievement. This study documented that a greater proportion of college students were thin compared with the general population and that heavier females received less college financial support from parents than thinner females (Crandall, 1995). Although frequently cited, there is no current literature on these phenomena despite major changes since the 1990s including a much higher prevalence of obesity and the economic downturn known as the "Great Recession." Thus, in the interest of pursuing replicable science, the present study examined the role of weight stigma in higher education in 2 studies using ethnically diverse samples of first-year college students. We found that the average Body Mass Index (BMI) and BMI distribution in our samples were still significantly lower than a nationally representative sample, regardless of gender and ethnicity. We also found that, among females, self-funded students had higher BMIs than parent-funded students. In one sample, this was also the case for males. Together these findings suggest that not only are heavy young adults perhaps less likely to be in college than their thin counterparts, but they may also receive less support from their parents. This points to the possibility that weight stigma may undermine educational achievement in today's youth, which could have negative downstream consequences for lifelong socioeconomic, health, and well-being outcomes.

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