β-Hydroxybutyrate phenylalanine (BHB-Phe) is a ketone body metabolite resulting from the conjugation of β-hydroxybutyrate (BHB) with the essential amino acid L-phenylalanine. It is synthesized endogenously by cytosolic non-specific dipeptidase 2 (CNDP2) in the process of ketogenesis. In diet-induced obese (DIO) mice, a daily dose of BHB-Phe (50 mg/kg) leads to a reduction in food intake, body weight, and the respiratory exchange ratio (RER) without altering activity, oxygen consumption (VO2), or carbon dioxide production (VCO2).