Fiber does all sorts of good things for the body, from preventing disease by cleaning out the GI tract to filling us up faster. But in relation to exercise, there is a better method to take when consuming fiber.
Let’s start off by defining fiber. Fiber is the polysaccharide found in plants that is not digested or absorbed in the small intestine. Overall, the daily intake of fiber should be between 25-35g for adults. However, the daily intake of fiber in the United States is about half that amount. Most nutrition experts agree that consuming too much fiber can result in discomfort and a great change in digestion, but overall is beneficial and rarely has adverse effects.
Before we get in to how fiber and exercise work together, it is important to know the two different kinds of fiber that do very different things. There is insoluble fiber and soluble fiber, referring to its solubility in water. Insoluble fiber stays relatively unchanged when coming in contact with fluids. Soluble fiber will dissolve or enlarge in water. This type of fiber binds to fat and cholesterol in the intestinal tract and delays transit time through the stomach and intestines. It is soluble fiber that helps promote satiety to help you feel full longer. Insoluble fiber, on the other hand, does not readily dissolve in water, making it easier to pass through the GI tract intact and quickly, increase in volume and weight as it goes through. This helps to stimulate sliding-like contractions in the colon, helping to alleviate constipation.
The important thing before working out is to fuel up for the energy needed for the activity. Insoluble fiber from whole wheat sources helps give us the healthy carbohydrates our body needs, as well as the energy it needs. This fiber will also help alleviate digestive discomfort and bloat. Soluble fiber is better to take post workout, being that it slows the release of glucose into the system and helps prevent fat storage. When you are consuming soluble fiber post workout, be sure to get it in your diet within an hour of exercising. But when you just finished an extensive workout, a full, hearty meal may not be the best choice. Fiber-rich snacks would be a better grab within that first hour. A medium size apple with peanut butter or some flax and fruit oatmeal will help give you a few grams of soluble fiber along with protein.
Good sources of insoluble fiber include whole grains, bran, nuts, soy, and vegetables. Opt for sources of whole grain instead of refined flour.
Soluble fiber is found in most fruits, beans, flax, and oats. What’s important is that you spread your fiber intake out throughout the day instead of trying to get most of it in one meal. For example, you could shoot for roughly 8 grams at every meal and easily get a few grams in with every snack.