If you just cut calories -- and don't exercise -- you harm your bones two ways: you may cut nutrients needed to maintain strong bones, and you don't stimulate bone growth, indicated the study that looked 46 men and women with an average age of 57.
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This suggests you'd want to do diet and exercise together to have less harmful effects on the bone," said lead author Dr. Dennis Villareal, an associate professor of medicine at the Washington University School of Medicine in St. Louis.
The study highlights the benefit of the "triad" of bone-building habits: eating calcium-rich foods or taking supplements, engaging in weight-bearing exercise and maintaining a stable hormone status, said Christine Gerbstadt, a registered dietician and a spokesperson for the American Dietetic Association.
Lifting weights pulls on the skeleton, stimulating new bone production.
"The main point is that exercise is far more important than most people give it credit," Gerbstadt said.
Also worthy of note, she said, is that weight-bearing exercises beyond walking are invaluable to bone health. Doing bicep curls and lunges with weights -- even with a 16 oz. water bottle in each hand -- can improve bone density immensely.
And although it's often portrayed as a disease of women, osteoporosis can also strike men, and both sexes can show signs in their 30s.