Simple fiber adds to your diet that make sense, nutritionist says New York-based certified holistic nutritionist Robin DeCicco shares the importance of fiber for overall health. NEW You can now listen to Fox News articles! Fiber is known to be a crucial part of a healthy diet, promoting fullness and gut health. As trends like "fibermaxxing" make high-fiber eating more popular, understanding the best sources is increasingly important for individual health, according to nutritionists. Longevity