hormones
Menopause
The end of menstrual cycles, usually between ages 45–55, marked by declining estrogen and metabolic shifts.
Menopause typically reduces BMR modestly, shifts fat to the midsection, and accelerates lean-mass loss. Resistance training, adequate protein (1.2–1.6 g/kg), 7–9 hours of sleep, and conservative deficits preserve most metabolic health. HRT can restore some lean mass — discuss with a physician.