Doctoral Dissertation Research: Appetite regulation in energy-limited settings

Appetite regulation (AR) drives food intake, which is especially critical during childhood when sufficient food must be ingested to ensure growth and development. Childhood AR is particularly relevant because it is associated with adult appetite and food intake, as well as metabolic disease risk (e.g., obesity). Throughout life, AR is affected by leptin, a hormone secreted by adipose tissue, which informs the brain about energy levels in the body. However, studies have revealed that leptin levels vary in ways that are not associated with adiposity, but with energetic stress and possibly other environmental and physiological conditions. While humans have lived in food-scarce environments for most of our history, current knowledge of AR and leptin levels are mostly based on populations that live in food-abundant places. To assess how childhood AR is shaped by the environment, this doctoral dissertation project studies food intake and leptin levels among children that live in subsistence-based groups. The study integrates evolutionary, biocultural, and adaptive models, reframing leptin as an evolved endocrine signal for managing children's energy needs. Results are shared with participant children’s families and are used to promote science education. Hands-on STEM research experiences are provided for undergraduate students. This study investigates homeostatic (leptin/adiposity) and non-homeostatic (appetite traits/eating behavior) aspects of AR among school-age children (n = 100, age 4-12 years). The study’s objectives are to: (1) define the relationship between children’s leptin and adiposity, (2) identify key ecological drivers of variation in children’s leptin and appetite regulation, and (3) assess how children’s appetite traits are associated with leptin and adiposity. Two validated questionnaires are applied to: (1) assess appetite and eating habits in each participant child, and (2) characterize lifestyle and household conditions. Anthropometric measures of height, weight, and BMI are collected and standardized to age- and sex-specific z-scores. Leptin levels are measured from dried blood spots. The study's methodological approach advances NSF priorities for investments in biotechnological innovation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.