You probably already know that vitamins are vital to your health. But did you know vitamin D can play a role in weight gain? In a study of older women, those with too little vitamin D gained more weight than those who had enough. And most women—78 percent!—had insufficient levels.

You can get vitamin D through direct exposure to the sun; foods like salmon, fortified orange juice, yogurt and whole grain cereals; or supplements. Sunlight is a great source, but UV rays can damage your skin. Let yourself soak up the sun’s beauty benefits for 20 minutes, then slather on the sunscreen, stat!

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