eLife Assessment
This important manuscript presents the Crunchometer, an open-source and low-cost acoustic system for high-resolution quantification of biting and chewing in mice. The work addresses a need for reliable measures of food consumption and feeding microstructure, and the tool has broad relevance for studies of ingestive behavior, appetite circuits, hypothalamic function, and pharmacological interventions. The evidence supporting the methodological advance is convincing, and the Crunchometer outputs were carefully validated against human observer scoring, reliably distinguished biting and chewing events, and captured changes in feeding behavior across different foods, physiological states, and semaglutide treatment. The study also demonstrates that the system can reveal biologically meaningful features of feeding, including meal structure, bite and chew dynamics, and altered consumption patterns after pharmacological manipulation. A significant additional contribution is the identification of previously unrecognized meal-related neurons in the lateral hypothalamus, providing novel circuit-level insight into solid food consumption and naturalistic feeding behavior. Although some neuroscience conclusions remain more preliminary than the methodological validation, the study provides strong evidence for the utility of the Crunchometer and will be of interest to researchers studying ingestive behavior, hypothalamic circuits, and metabolic regulation.