1 — What is a high fiber diet?

In order to keep this answer simple I will define the high fiber diet as a diet where an adult consumes 25-35 grams of fiber each day. This recommendation comes from the U.S. Department of Agriculture (aka USDA).

2 — Where does fiber come from?

Just about all fiber comes from plants, bushes, vines or trees. So this comes from the things we eat such as fruits, vegetables and grains. There are many different types of fiber but the three that are most important to the health of the body are insoluble fiber, soluble fiber, and prebiotic soluble fiber. Prebiotic soluble fiber is the newest discovery in terms of these types of fibers so I will focus on the other 2 types to keep things simple. 

3 — How do the different types of fiber work in the body?

This is a great question and often results in a complex answer. However, my patients know that I’m not a fan of making things more complex than they should be just to sound fancy or smart. So I will keep things simple when I discuss each fiber’s applications within the body.

• Insoluble fiber does not dissolve in water and it is not broken down by the bacteria that lives in the colon, which is also known as the large intestine. Instead, it retains water and by doing this it helps to promote a larger, bulkier, and more regular bowel activity in a person.   

• Soluble fiber is broken down or used by the good bacteria in the colon as a food source or for nourishment. When these good bacteria grow and thrive, many health benefits occur in both the colon and the body.
  
  

4 — What are benefits of eating a high fiber diet?

Most people know that eating fiber is a healthy way to address and relieve constipation symptoms. However, having enough or high amounts of fiber in your diet do many other things for your overall health. This includes preventing disorders like hemorrhoids and diverticulosis, lowering blood cholesterol and triglyceride levels, lower blood sugar levels in people with diabetes, and even helping with weight loss. Perhaps one of the biggest benefits of having a high fiber diet is the removal of certain toxins and cancer causing agents from the colon which decreases the likelihood of someone developing colon cancer. To put it more plainly, the additional fiber in the diet helps ensure that harmful substances are more likely to be swept out of the body before they can cause problems. 

5 — Which foods have high fiber content?

This list can be long if I were to list each food item individually. So instead I will place them into categories to make it easier to identify particular foods.

• Whole Grains – Wheat, oats, barley, wild or brown rice, amaranth, buckwheat, bulgur, corn, millet, quinoa, rye, sorghum, teff and triticales. By far, wheat, oats and wild or brown rice are most common. Seven-grain, dark rye, cracked wheat, and pumpernickel breads are also good choices. White bread, baked goods and rolls almost always are made from wheat flour. Wheat flour is white because most of the fiber, vitamins and other nutrients have been removed. Try not to buy enriched grains and instead buy whole grains. The word enriched implies a good and healthy product. On the contrary, enriched means that most of the fiber has been removed and a few vitamins were added.  

• Fruits – Those that come from trees, such as apples and pears or from bushes or vines. You should eat a wide variety of fruits, preferably as a snack or with meals. In many cases, the skin of a fruit, such as apples, will contain much of the insoluble fiber while the pulp contains most of the soluble fiber. Apples, bananas, oranges, strawberries all have around 3 to 4 grams of fiber. Raspberries win the fiber race at 8 grams per cup and exotic fruits are also good sources of fiber. An example of this would be a mango, which has 5 grams of fiber, a persimmon, which has 6 grams of fiber, and 1 cup of guava, which has about 9 grams of fiber.

• Vegetables – Of course you have been told before to eat a wide variety of vegetables, and they should be a staple of lunches and dinners. Frozen vegetables retain as much nutrition and fiber as fresh vegetables. In general, the darker the color of the vegetable, the higher the fiber content. Carrots, beets, and broccoli are fiber-rich. Collard greens and Swiss chard have 4 grams of fiber per cup. Artichokes are among the highest-fiber veggies, at 10 grams for a medium-sized one.

• Legumes, Beans, Nuts and Seeds – Legumes are plants that bear fruit in their pods, and are further categorized as beans, lentils, peas, and peanuts. Foods in the legume family are among the most naturally rich sources of fiber. They are low in fat, plentiful in protein, and pack a powerhouse of nutrients. Also beans are an excellent fiber choice and offer the most fiber per calorie. Navy (white) beans are the most fiber-rich, but all beans are fiber-packed. Any of them would be a good choice for your shopping cart including garbanzo, soybeans (edamame), kidney (red), lima, or pinto beans. Beans are also high in protein, so if you’re cutting back on red meat, they’re a healthy, filling substitute. Peanuts aren’t really a nut at all, but grow in a pod and so are considered a legume. A handful of nuts can also make a healthy, high-fiber snack and they are a big reason why I eat a lot of trail mix. They are also a good substitute for sweets such as candies and baked sweet goods.
  
  

6 — What can you do if you don’t receive enough fiber from the foods you eat?

This is a question that I have run into quite a bit in my years caring for patients. As much as I want patients to eat fiber in their daily diet some just won’t be able to reach the high fiber levels that I have previously mentioned. So when that happens I then turn to the fiber supplements to fill in the void that may still exist despite patients best dietary efforts. There are a variety of fiber supplements available on the food or pharmacy shelves. To keep things simple I will review 3 of the more common supplements. I must also mention that these 3 forms of supplements come in a variety of formulations such as pills, powder that can be mixed in liquids so that you can drink them, and even gummies! That’s right there are fiber supplements that come in gummy snack form so that they are a bit more tolerable to eat or ingest.

• Psyllium – This soluble plant fiber comes from the Psyllium plant and acts to retain a lot of water. When it is exposed to water in the body it becomes gel-like and adds bulk to the stool to relieve either constipation or diarrhea. Metamucil is a form of psyllium fiber supplements.  

• Methylcellulose – This insoluble fiber is a synthetic product made from cellulose that does dissolve in water. This means it is not broken down or digested in the intestines. Instead it acts as an emulsifier, meaning it blends oils and water, and becomes gel-like to add bulk to the stool. Citrucel is a form of methylcellulose fiber supplements.

• Inulin – This is a soluble prebiotic fiber produced by many plants and is composed mainly of fructose. It is found in many foods and it adds bulk to the stool to relieve constipation and diarrhea. It is available in a supplement as generic inulin and in Fiber Choice supplements.

To wrap up this discussion about high fiber diets I will discuss some very practical ways of adding more fiber to your diet or daily routines and things that I believe you should consider when increasing your daily fiber intake.

1. I always instruct patients to increase fiber intake slowly to avoid intestinal gas that may occur when fiber intake is increased too rapidly.
   
   
2. Remember to start the day with a high fiber breakfast cereal if possible. Add a cup of yogurt with high fiber breakfast cereals, fruit, flax seeds or chia seeds to meet half of your daily fiber requirement in one powerhouse breakfast.
   
   
3. Switch to whole grain breads, pastas and rice and pack in more fruits by adding them to hot or cold breakfast cereal, yogurt or salads. You can also get more fiber in by making fruit a dessert.
   
   
4. I do recommend adding beans, lentils or peas to soups, salads or side dishes to step up the fiber content. I also recommend boosting the fiber content of soups and salads by cooking and adding whole grains such as whole wheat, barley, buckwheat, bulgur, corn, amaranth, brown rice, wild rice, quinoa, and farro.
   
   
5. Consider eating cut-up vegetables for snacks as many grocery stores offer precut carrots, broccoli, cauliflower, celery, and grape tomatoes if you don’t have time to cut up veggies.
   
   
6. Patients should try to drink 8 full glasses of water or other low calorie liquid each day because fiber acts like a sponge absorbing large amounts of water. So by retaining water in the colon it results in softer stools and easier bowel movements.
   
   
7. Lastly, read food labels! The amount of fiber contained in a serving is clearly labeled on all packaged foods.