Cortisol causes bone cells to stop growing or to release calcium into the bloodstream. Excessive cortisol levels can lead to osteoporosis. Cortisol causes some fat cells to release their fats known as triglycerides, and causes other fat cells to absorb excess triglycerides.
One effect of the stress response is to break down adipose (fat) cells to move triglycerides (fat molecules) into the bloodstream for more energy. Your body would use the energy from triglycerides in the “fight or flight” physical responses to stress. But do you have increased physical activity in response to most of the stresses you experience in the modern world? Most people don’t. Instead of burning the triglycerides, cortisol causes these unused fats to be re-deposited in the adipose tissues surrounding the belly. [Epel, E.S., B. McEwen, T. Seeman, et al. Stress and body shape: stress-induced cortisol secretion is consistently greater among women with central fat. Psychosomatic Medicine 62:623-632, 2000]