Glucagon-like peptide-1 agonism - GLP-1, common in obesity medicines - is not essential to weight management, according to preclinical research led by Richard DiMarchi and Matthias Tschöp, with funding from their startup company Bluewater Biosciences.
Maintaining a caloric deficit also causes a sustained reduction in basal metabolic rate. Our bodies are very good at homeostasis.
I second the opinion that calories are a reductionist metric for fat loss. Much better to think in terms of biology.