Your takeaway? Popping 1,000 mg of both calcium and vitamin D daily—preferably before you work out—may help you ward off age- or exercise-related bone loss, the research indicates. If you’re not into pills, yogurt, milk, salmon, and most dark green vegetables are good calcium sources. D is harder to come by, but fatty fish, egg yolks, and 15 minutes of sunlight are all D-lightful options.