“Think of your bones as a “bank” where you “deposit” and “withdraw” bone tissue. During your childhood and teenage years, new bone is added (or deposited) to the skeleton faster than old bone is removed (or withdrawn). As a result, your bones become larger, heavier, and denser.

For most people, bone formation continues at a faster pace than removal until sometime after age 20. After age 30, bone withdrawals can begin to go faster than deposits. If your bone deposits don’t keep up with withdrawals, you can get osteoporosis.”

National Institute of Arthritis, Musculoskeletal and Skin Diseases.