Fiber is something the body needs but never actually digests…in fact, it remains more or less the same from plate to toilet. It comes in two varieties, soluble and insoluble, and most plant-based foods contain a mixture of the two. Soluble fiber turns to gel in the stomach and slows digestion, which helps lower cholesterol and blood glucose. Insoluble fiber, on the other hand, remains unchanged all the way to the colon, making waste heavier and softer so it can shimmy through the intestines more easily. Regardless of these differences, neither type of fiber is ever absorbed into the body.
Skipping out on a daily dose of fiber often leads to constipation, which can make going to the bathroom painful and uncomfortable—hence the term “backed up.” Eating too little fiber can make it tough to control blood sugar and appetite because fiber regulates the speed of digestion and contributes to feeling full. There can be too much of a good thing, though. Overdoing it with fiber can move food through the intestines too quickly, which means fewer minerals get absorbed from food. It can also result in uncomfy gas, bloating, and cramping, especially when fiber intake is dramatically increased overnight
What’s the magic amount? The Institute of Medicine recommends that men under 50 eat about 38 grams of fiber each day and women consume 25 grams. Adults over 50 require less fiber, 30 grams for guys and 21 grams for ladies, due to decreased food consumption.