Black beans are a good source of iron. Thing is, the iron in plant foods, known as non-heme iron, isn't as readily absorbed as the iron you'll find in meat. "Just 2% to 20% of the iron in plant foods makes its way from your digestive tract into your blood, compared to 15% to 35% from heme animal-based iron," says Cynthia Sass, RD, MPH, Health's contributing nutrition editor and author of Slim Down Now: Shed Pounds and Inches with Real Food, Real Fast ($27; amazon.com). That's where vitamin C-rich foods, like red bell pepper, come in. They can increase the absorption of non-heme iron by six times, Sass says. Her go-to dish: black bean tacos topped with sautéed red bell peppers.