INS and obesity due to melanocortin 4 receptor deficiency: Obesity acts through several pathophysiological mechanisms, including elevated plasma levels of free fatty acids and pro-inflammatory cytokines and adipokines, intracellular non-adipose tissue lipids (like liposomes), and ectopic adipose tissue depots (especially the visceral compartment), which can cause oxidative stress, systemic inflammation, insulin resistance, and sympathetic nervous system hyperactivity [15,16,17].