Photo: Olha_Afanasieva/istockphoto

1 of 5
In Your 20s

The Food: Yogurt
Why: For the bone-building calcium. We stop building bone mass around age 30, making your 20s make-or-break (no pun intended) time for gaining bone strength. At this age, you need 1,000 mg of calcium per day to meet your recommended intake–8 ounces of plain low-fat yogurt has 42 percent of that. (Just watch the sugar in any low- or non-fat varieties, as it's often added for taste.)

Where else you can get calcium: You know it's present in other dairy products, like milk and cheese, but there are a lot of non-dairy options too, says Kristin Kirkpatrick, RD, the manager of wellness nutrition services at the Cleveland Clinic's Wellness Institute. Tofu, salmon and leafy greens like kale are all good sources.

The Food: Eggs
Why: Their yolks have vitamin D, which helps your gut absorb all that calcium you're taking in. "You really need both to build up your bones," says Kathryn Sweeney, RD, a dietitian in the department of nutrition at Brigham and Women's Hospital in Boston.
Where else you can get vitamin D: Swordfish has lots of vitamin D, but it's also among the highest-mercury fish, so eat it sparingly. Sardines and canned tuna are high-vitamin-D foods you can eat as often as you like.