Known as sand piranhas, Excirolana chiltoni are tiny crustaceans that nibble at your feet – and draw blood – if you hang out on the wet sand at the beach. They live on the Pacific coast of the U.S.

But what if there was a simple, science-backed visual tool to guide you at every meal? Well, there is! It's called the Healthy Eating Plate, created by nutrition experts at Harvard's T.H. Chan School ...