Fiber is the part of plant-based foods that our bodies can't digest. It passes through our digestive tract without providing nutrition or calories, and yet it is very healthy for us.
Fiber helps to keep our bowel movements regular and ward off certain diseases. Carcinogens in our intestines bind to it and move through our colon more quickly than they otherwise would, reducing our risk for colon cancer. Fiber also helps transport cholesterol out of our body, reducing our risk for heart disease.
Populations that eat greater amounts of fiber-rich foods are generally healthier. While all of the reasons for this are not known, it may be because the fiber-rich foods themselves are healthier. Perhaps fiber's greatest value, however, is in helping to keep us slim.
Fiber makes us feel full sooner and stays in our stomach longer than other substances we eat, slowing down our rate of digestion and keeping us feeling full longer. Due to its greater fiber content, a single serving of whole grain bread can be more filling than two servings of white bread. Fiber also moves fat through our digestive system faster so that less of it is absorbed.
Meat and dairy products contain no fiber, and refined grains have had most of their fiber removed. To increase your intake of fiber, eat more whole and natural foods, and fewer processed foods. Some good examples of fiber-rich foods include:
Products labeled "whole grain" are made with the complete grain kernel, whether the grain remains intact as in oatmeal or it is ground to make bread, pasta or cereal. Cracked wheat is also made from the complete kernel, but don't be mislead by wording like "100% wheat" or "multi-grain." Don't be misled by color, either. Most wheat bread is almost identical to white bread except that caramel coloring has been added to make it look more natural.
Refined grains like white rice and those used to make white bread and sugary breakfast cereals have had most of their fiber and nutrients stripped away. They turn into blood sugar (glucose) so fast that, like sugar itself, they can cause a spike in our insulin level. This tells our body that plenty of energy is readily available and that it should stop burning fat and start storing it.
However, the greater concern with the insulin spike is not that it tells our body to start storing fat. Whatever we eat and don't burn up eventually gets turned into fat anyway.
The greater concern is that the insulin spike is followed by a drop in insulin level that leaves us feeling tired and hungry and wanting to eat more. The unfortunate result of this scenario is that it makes us want to eat something else with a high sugar content. When we do, we start the cycle all over again. Eating foods with plenty of fiber will help keep our blood sugar at a more consistent level.
Adding more fiber to your diet will likely help you lose weight and improve your health, but do it gradually. Rapid increases in consumption of fiber may result in gas or diarrhea.
And be sure to drink plenty of fluids when adding fiber to your diet. While fiber is normally helpful to your digestive system, without adequate fluids it can cause constipation instead of helping to eliminate it.