Key Points

  • Sleep debt measurably alters hunger hormones, increasing appetite and cravings the next day.
  • Chronic stress raises cortisol, which is linked to increased abdominal fat storage.
  • Rate of change and body composition matter more than a single static number.
  • Rapid, severe restriction is rarely sustainable and often works against long-term metabolic health.
  • A clinician can rule out thyroid, hormonal, or medication-related factors before assuming behavior alone explains a change.