Amy Kimberlain, Registered Dietitian at Baptist Health South Florida, explains soluble fiber versus insoluble fiber: "The soluble fiber is that gel-like substance that is helping to move things through and does not let things adhere to the artery walls," she says. This type of fiber can be found in oatmeal and apples, for example.
According to her, the insoluble fiber is one that does not dissolve in water and it is moving things through the digestive tract. It can be found in wheat flours and lentils.
