A number of pressing nutritional issues face mankind. In the US and other developed countries strategies are needed to address the ever-increasing epidemic of obesity and related chronic diseases and in impoverished countries severe acute malnutrition directly contributes to deaths of more than a million children under the age of 5 each year globally. To address these concerns researchers will conduct the following objectives: 1) compare the effects of inulin and fructo-oligosaccharides against a maltodextrin placebo in obese children, using a double-blind randomized controlled trial, to study weight loss, fecal microbiota and their functions; 2) among children from low-to-middle income countries with severe acute malnutrition (SAM) to: a) longitudinally characterize epigenomic, and metabolomic responses to SAM treatment; b) assess amino acid content of hair samples taken before, during, and after therapy to identify biochemical markers of nutritional status and therapeutic response, and; c) investigate the role of a newly identified hormone ¿ Asprosin ¿ in the recovery of satiety during SAM refeeding therapy by integrating serial measurements in plasma with clinical nutritional data on caloric intake and weight recovery; and 3) conduct a clinical trial adding black-eyed peas to diets of young children at risk for stunting. Determine efficacy in reducing stunting and analyze fecal sample to understand potential mechanisms by which the food supplement ameliorates stunting. Assess dietary compliance in a novel, quantitative manner using a urinary biomarker for black eyed peas. Currently quercetin and ferulic acid are candidates for this biomarker. Additionally, breastfeeding has enormous health benefits to both infant and mother and continued efforts to understand the biology of mammary development and lactation are important to improving both infant and maternal health. Thus we will undertake this objective to further our knowledge: 4) select inbred mouse strains with phenotypic extremes in milk production will be used to: a) identify genomic variants along with intestinal and mammary-expressed genes that differentiate low and high milk production, and b) determine the extent to which genome-driven differences in milk production and mammary gene expression are directly mediated through host-dependent differences in the intestinal and/or mammary tissue microbiome.