Adjusting to Increased Fiber

It can take time for your body to adjust to more fiber!

Fiber is critical to good health. It feeds the important good bacteria (and other microbiota) in our bodies. Our microbiome plays a vital role in digesting food, absorbing (and even synthesizing) nutrients, training our immune system, maintaining gut integrity, and much more. The good bacteria feed on fiber and help you digest it; they can die off on a low-fiber diet, which can make digesting fiber hard at first. If your diet does not currently contain a lot of whole grains, starchy vegetables, and legumes, your body may have already adjusted to a low fiber diet. 

Switching to a high fiber diet can cause unpleasant symptoms at first: abdominal bloating, stomach pain, intestinal gas, fatigue, moodiness, cravings, and/or headaches. This can be quite painful, but it is not a sign that this diet doesn’t work for you. It is only a sign that your body has to readjust to the new foods. If you are worried, increase the fiber more slowly. Your microbiome will begin to flourish, enabling you to efficiently handle the fiber which is vital to our good health!

Some gas may be unavoidable, but over time it should not be painful. If is helpful to know that: “Gas production is a normal, healthy function of the intestines which appears to protect the colon against genetic damage leading to cancer. It dilutes carcinogens, stimulates beneficial bacterial growth, favorably alters the gut ph, and improves the function of the epithelial cells of the colon” (Becoming Vegan, 87).

Note: The advice on this page is not intended as medical advice for people already experiencing chronic disease. See note below.

Useful Strategies

  • Cook foods thoroughly and chew foods thoroughly. (The more you cook and chew, the less work your digestive system has to do to break down the food.)
  • Use beans sparingly until your body has adjusted; increase slowly.
  • Use lentils, split peas, and other small legumes which are less problematic than the larger beans.
  • Try Beano or other products with digestive enzymes that can help prevent gas.
  • Soak legumes overnight before cooking. (If this does not help, a sure-fire way is to sprout the beans: cover the beans with water for 12 hours, drain off the water, then spread out the beans on a damp paper towel and let sit for about 12 hours. When you notice tiny white shoots (1/16th inch long) begin to appear, the beans are ready to cook. Cooking time is less after sprouting.
  • Continue to slowly increase the amount of fiber in your food and then consume it regularly. Good bacteria feed on this fiber, and the more good bacteria there is, the more easily they can digest the fiber.

Plant Foods that Tend to Produce Gas

For some people, certain plant foods tend to produce gas even if they are used to a WFPB diet. These foods include: legumes (especially beans, but also split peas and lentils) and some cruciferous vegetables (like cabbage, cauliflower, broccoli, and Brussels sprouts). Other less common gas producers include: onions, bagels, pretzels, prunes, apricots, carrots, celery, green peppers, bananas, and wheat germ. Each person can be different, so pay attention to what seems to affect you the most. Other sources of gas, especially food additives: inulin, chicory root, sugar alcohols. See: “What Foods Cause Gas?”

If you find one or more of them affect, you might eliminate these particular foods or use them sparingly.

For More on the Microbiome

I wrote a 10-article series for Meridian Magazine on the microbiome and human health: “Will the Destroying Angel Pass Us By?”

Experiencing Chronic Disease?

The advice on this page is not intended to be medical advice for people with chronic disease. Please refer to competent medical advice if you have a severe gastrointestinal disorder, auto-immune disease, food allergy, type 2 diabetes, or other chronic disease. While a high fiber whole food, plant-based diet can be key to your recovery, you may need expert advice on how to implement this diet (and adjust your medications) given your specific condition. Otherwise, you run to risk of some symptoms getting dramatically worse.

Last updated March 12, 2016