Acai berries have a deep purple hue and a sweet, tart flavor similar to that of a blackberry. They're one of the most popular superfoods out there, and are packed with an outstanding amount of antioxidants and plant chemicals. It's challenging to find the berries in the produce section of your grocery store, so the best way to get these guys into your diet is with a superfood smoothie. Most grocery stores stock frozen acai packets. Choose the purest option possible, meaning no added sugar.