ABSTRACT—METABOLISM AND METABOLIC HEALTH (MMH) CORE Investigators interested in mechanisms underlying the pathophysiology of obesity, diabetes and related metabolic diseases will benefit from a comprehensive analysis of components regulating energy balance, macronutrient combustion and metabolism in live animals. Simple tests that compare food intake to weight gain, or that measure metabolically-relevant analytes from a single static condition, fail to fully capture nuanced bioenergetic and metabolic phenotypes, changes in feeding behaviors, or alterations of body composition. Therefore, the Metabolism and Metabolic Health (MMH) Core has been designed and structured to provide investigators with expert consultation, state-of-the-art instrumentation, and technical support to assess—in live mice—energy balance, energy intake (EI) and digestion, energy expenditure (EE), metabolic efficiency, EI-EE coupling phenotypes, macronutrient metabolism, hormone action and secretion, body/tissue composition, and associations with the microbiome and xenometabolome. The MMH Core will be service-oriented, client-facing, and research-supportive. The MMH Core will be staffed by a Leader, co-Leader, Core Coordinator, Technical Specialists, and 5 Scientific Consultants. The mission of the MMH Core will be accomplished through the following 2 Specific Aims: Specific Aim 1: Provide clients with innovative and unique assets and approaches to deeply- characterize key nodes involved with energy balance, food intake, glucose and triglyceride metabolism, metabolic hormone sensitivity, body composition and gut microbiota metabolism in live mice. Specific Aim 2: Provide clients with consultation services focused on study design and interpretation of results in the areas of metabolic physiology, obesity, and diabetes. Under these specific aims, the MMH Core will carry out the following activities: • Providing acute, mid, and long -term assessments of EI and sensitivity to EI-regulating hormones