ObjectivesMarket integration seems to induce gender‐specific generational change in health‐related perceptions of body size. We predicted that among the Qom of Argentina, younger women would perceive comparatively thinner bodies as healthiest, demonstrating thin‐idealizing body norms, and older women would retain culturally rooted perceptions of heavier bodies as healthiest. As traditional and globalized body size ideals are different for men, we predicted that men would perceive normal bodies as healthiest and would not exhibit generational differences.MethodsWe asked Qom adults (n= 273) residing in Namqom, Argentina to choose the healthiest body size from the Stunkard Figure Rating Scale (FRS). We performed multiple linear regression with age, gender, and body mass index (BMI) predicting healthy‐body perception score.ResultsA majority of women chose overweight bodies as healthiest. As predicted, older women preferred heavier bodies compared to their younger peers; this generational effect was stronger among women clinically defined as underweight (BMI ≤19.99 kg/m2), and “normal” weight (20.00 kg/m2 ≤ BMI ≤24.99 kg/m2), as compared to women clinically defined as overweight (25.00 kg/m2 ≤ BMI ≤29.99 kg/m2) or obese (≥30.00 kg/m2). Men exhibited no generational effects and largely perceived bodies corresponding to a “normal” BMI as healthiest.ConclusionsAmong Qom women, there is evidence for the adoption of the idealization of thinness as healthy alongside traditional perceptions that fat bodies are healthy.

Objectives: Postpartum amenorrhea (PA) affects the length of interbirth intervals and thus is intimately related to human life history strategies. PA duration appears to be influenced by maternal energetic status. In humans, as in other mammals, sons are costlier than daughters. Thus, we hypothesize that, in energetically constrained environments, a newborn's sex should be associated with PA duration. Methods: We analyzed data from two natural fertility populations in which mothers have differing energy budgets: Qom women (n = 121) from a periurban village in Argentina, who have a comparatively calorically dense diet and are sedentary (prepregnancy mean BMI = 24.8 ± 4.5 kg/m 2 in 1997), and agropastoral Kaqchikel Maya women (n = 88), who have a comparatively calorically restricted diet and high physical activity levels (mean BMI = 21.8 ± 3.7 kg/m 2). We predict that (a) mothers of sons exhibit longer PA duration than mothers of daughters and (b) this association between offspring sex and PA duration is stronger in the Maya, who have smaller energy budgets. Results: Maya mothers with sons exhibited estimated mean and median PA durations that were 1.34 times the estimated mean and median PA duration of mothers with daughters (p = 0.02). Among the Qom, mean, and median PA duration did not differ significantly in relation to offspring sex (p = 0.94). Conclusions: Maya mothers with sons exhibited longer PA duration than those with daughters. This phenomenon was not observed in the well-nourished Qom, possibly due to "buffering" effects from larger energy budgets. Offspring sex may influence birth spacing and maternal life history strategies in energetically constrained environments. 1 | INTRODUCTION The life history strategies of women, like those of all organisms, are mediated by trade-offs in the allocation of finite resources among survival, maintenance, and reproduction (Stearns, 1992). The optimization of maternal investment-female allocation of resources to offspring-is paramount to the maximization of women's lifetime reproductive success, that is, the number of offspring reared to reproductive age (Ellison, 2003; Hill &

The human milk microbiome is thought to partly contribute to the assembly of the infant gut microbiome, a microbial community with important implications for infant health and development. While obesity has well-established links with the adult gut microbiome, less is known about how it affects the human milk microbiome. In this scoping review, we synthesize the current literature on the microbial composition of human milk by maternal weight status, defined broadly as BMI (prepregnancy and postpartum) and gestational weight gain (GWG). This study followed the a priori protocol published in Prospero (registration #: CRD42020165633). We searched the following databases for studies reporting maternal weight status and a characterization of milk microbiota through culture-dependent and culture-independent methods: MEDLINE, Embase, Web of Science, CINAHL, and Scopus. After screening 6,365 studies, we found 20 longitudinal and cross-sectional studies investigating associations between maternal weight status and the composition of the milk microbiome. While some studies reported no associations, many others reported that women with a pre-pregnancy or postpartum BMI characterized as overweight or obese, or with excessive GWG, had higher abundances of the genus Staphylococcus, lower Bifidobacterium abundance, and lower alpha diversity (within-sample diversity). This review suggests that maternal weight status is minorly associated with the composition of the milk microbiome in various ways. We offer potential explanations for these findings, as well as suggestions for future research.

The aim of this study was to investigate the relationship between media, body norms, and body image among the Qom, a market-integrating indigenous population in Argentina that has historically idealized larger body sizes.Methods: With men and women (n = 87), we measured frequency of media/ technology use through a Likert-type questionnaire. Using the Stunkard Figure Rating Scale, we asked participants to select the most healthy and ideal body size for their gender, as well as their own body size. We calculated body dissatisfaction as the difference between ideal and own body size. We conducted semi-structured interviews to describe the role of media in body norms and body image.Results: Media exposure was not significantly associated with perceptions of the "healthiest" or most "ideal" body sizes, nor body dissatisfaction. Men and women perceived categorically "middle-range" body sizes as both healthy and ideal, differing from a similar study in 2010, where larger bodies were favored.Interviews revealed that: media is not recognized as affecting body norms and body image, but is conceptually associated with cultural loss (Theme 1); a "dual stigma" of fatness and thinness is perpetuated by peers, family, and healthcare providers (Theme 2); and body acceptance is highly valued (Theme 3). Conclusion:In this context, while some body norms have changed over time, the impact of media on body norms and image may be secondary to influences from individuals' social networks, and may be occluded by norms favoring body acceptance. | INTRODUCTIONBody norms are the sociocultural values that deem certain body sizes as healthy or unhealthy, good or bad, or attractive or unattractive, or in need to be changed (Hardin et al., 2018;McCullough & Hardin, 2013). Historically and cross-culturally, large bodies were valorized as symbols of beauty and health (Brown &

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