Every year, researchers and food scientists from the U.S. Department of Agriculture collect samples of thousands of common fruits and vegetables from grocery store shelves to test for upward of 250 different types of pesticides. Those most likely to pick up pesticides make up the Dirty Dozen, and those least likely make up the Clean 15.

The sweet potato has joined the ranks of the Clean 15 for the second year in a row, and its place on the list has jumped up two spots to No. 13, beating out watermelon and carrots. From its high levels of fiber and antioxidants for gut health to its support of healthy brain function, there's already a lot to love about the vegetable.

If you want to avoid the harmful effects of pesticides, consider adding more sweet potatoes to your diet (or any produce on the Clean 15 list, for that matter). When in doubt, try buying organic, as products in this category are known for carrying lower levels of pesticides, like members of the Clean 15.