Your bones are constantly being broken down and rebuilt. This process happens throughout your life, but you reach your peak bone mass — the strongest your bones will ever be — around age 30. After that, it's mostly about keeping what you have.
Calcium is the main mineral that makes bones strong. The recommended amount is 1,000–1,200 mg per day from food — not supplements. Good sources include dairy products, leafy greens like kale and bok choy, and canned fish with soft bones. Studies suggest calcium supplements may not be as beneficial as food sources and could carry some risks.
Vitamin D helps your body absorb calcium. Without enough vitamin D, even eating plenty of calcium-rich food won't fully protect your bones.
Exercise matters just as much as diet. Resistance training — lifting weights, using resistance bands, or doing squats and push-ups — directly stimulates bone formation. Swimming, while great for the heart, doesn't have the same effect because bones need to bear weight to strengthen.
Protein also plays a role. Research shows that people who eat more protein tend to have denser bones, especially as they age.
Women over 65 and men over 70 should talk to their doctor about getting a DEXA scan — a painless bone density test.