Schematic drawing to depict environmental challenges that may modulate food intake (FI) or energy expenditure (EE) via the preoptic area (POA) and POA>hypothalamus projections that could potentially mediate metabolic adaptations of FI or EE as outlined in this review. VOLT, vascular organ of the lamina terminalis; PVH, paraventricular hypothalamic nucleus; DMH, dorsomedial hypothalamus, LHA, lateral hypothalamic area; ARC, arcuate nucleus; Glut, glutamate; GABA, γ-aminobutyric acid; PACAP, pituitary adenylate cyclase-activating peptide; BDNF, brain-derived neurotrophic factor.