In a moment I’ll let you know how to eat to minimize or eliminate IBS, but first I’m going to explain how and why it is effective. Once you understand what’s going on, it will be clear why the diet for IBS works so well.
The most important thing to know is that your body has a “cleansing wave” that occurs regularly throughout the day. These are waves of activity that move through your intestines. The purpose of a cleansing wave is to clean out the small intestine.
When you eat, food is churned up in your stomach and mixed with stomach acid, which kills bacteria. Then the food is let into the small intestine where enzymes break up the food into molecules that can be absorbed into your body. When your small intestine has extracted the nutrients, what’s left over needs to be flushed out of the small intestine and into your colon. That’s the job of the cleansing waves.
Question: After the nutrients are extracted, what’s left in the small intestine? What needs to be flushed out? Answer: Indigestible carbohydrates like fiber and certain sugars (the sugars you don’t have enzymes for). Lactose-intolerant people, for example, don’t have the enzyme needed to digest lactose (the sugar in milk) so when digestion is finished and all the nutrients in the meal have been absorbed, lactose sugar would still be left in the small intestine.
These indigestible sugars and fibers become food for bacteria. That’s fine if the bacteria are in the colon. It is not fine if the bacteria are in the small intestine.
If the cleansing wave doesn’t come after digestion is finished, bacteria feed on leftover fibers and sugars and multiply. It’s called “fermentation” and it produces gas. The gas accumulates in the small intestine. It can’t be expelled as easily as gas in the colon, which is expelled through flatulence. In the small intestine, the gas accumulates, producing a feeling of bloating and pain. The gas can also create either constipation or diarrhea — depending on what kinds of bacteria or food are present. Different foods and different bacteria produce different gases. If the main gas produced is methane, it causes your intestines to slow down, producing constipation. If the main gas is hydrogen, it causes diarrhea.
These are the core symptoms of IBS: bloating, pain, diarrhea, and/or constipation.
Given all this, the two most important things you can do if you have IBS is to 1) make sure your cleansing waves do their job, and 2) give the bacteria in your small intestine less food to eat.
Question: What causes the cleansing waves to work? Answer: The period of no food in between meals. When you eat, your digestive system does its thing, extracting nutrients. When it’s finished, the cleansing waves begin and wash everything leftover into the colon (including the bacteria in your small intestine).
But if you eat more food before the cleansing wave starts, the digestive process starts again and the cleansing wave is postponed. The indigestible food left in the small intestine stays there, feeding bacteria, while the new food is mashed up in the stomach and released into the small intestine to be absorbed. All this while, the bacteria feeding on the leftovers of the last meal are still in the small intestine, multiplying and producing gas, causing pain, bloating, diarrhea and/or constipation.
And it can happen again and again. Some people soothe their painful guts by eating something more. If they do it before the cleansing waves start, and then do it again, the remains of their previous meals will continue to stay in their small intestine while the new meals or snacks are being digested. The bacteria keep fermenting and multiplying, and the gas keeps accumulating.
To avoid all this, the solution is to eat a meal and wait four or five hours before eating anything, which gives your migrating motor complex a chance to do its job and move the leftover food (and the bacteria) into the colon where it can be removed from your body or comfortably fermented.
So the first rule of the diet for IBS is to eat three meals a day and not eat or drink anything else (except water) the rest of the time.
The other thing you can do to reduce the pain, bloating, diarrhea and/or constipation of IBS is to give the bacteria in your small intestine as little food as possible. That is, eat very little that is indigestible. This entire article can be summed up like this: Starve the bacteria and wash them away.
Let me tell you something: The list of recommendations below will seem in many ways the opposite of what we’ve been told is good for our health. The IBS diet does not contradict what we’ve been told about eating. But in some ways, a healthy diet helps perpetuate IBS. You’ll find out why in a minute.
Here is a list of recommendations for IBS:
1. Don’t eat more than two pieces of fruit in a day. If you want faster results, don’t eat any fruit. The primary sugar in fruit is fructose, which is digested very slowly, allowing the bacteria in the lower part of your small intestine (where too much bacteria resides in people with IBS) to ferment it.
2. Avoid all lactose. Do not eat milk, cheese, yogurt, butter, sour cream, etc. Even for people who don’t have a lactose-intolerance problem, lactose is a difficult sugar for human bodies to digest, and those sugars linger in the lower part of the small intestine. So lactose feeds bacteria in your small intestine. Avoid it. Lactose-free milk products are fine, of course.
3. Avoid all sweeteners except glucose. If you must have sugar and glucose is not available, eat regular table sugar (sucrose) but limit it as much as you can. Completely avoid fructose, sucralose (an artificial sugar), sorbitol, mannitol, and corn syrup. All these sugars are difficult or impossible for your body to digest, so they feed bacteria in the lower part of your small intestine. Glucose, on the other hand, is absorbed very quickly — usually in the first two feet of the small intestine (the small intestine is fifteen feet long). So glucose leaves nothing for the bacteria to feed on. Glucose is also called “dextrose” on some labels.
4. Don’t eat raw vegetables very often. Non-starchy cooked vegetables are fine — no more than five cups a day. Raw vegetables are difficult to digest. Potatoes are the one exception to the non-starchy vegetable rule.
5. Eat potatoes, white rice, pasta, and white bread. I told you this would be the opposite of what we’re told is good for us. Some starches are digested quickly. Some are digested more slowly, and the slower ones make it to the lower part of the small intestine without being absorbed, so they feed the bacteria. We’ve all been told to eat more of the “slow carbohydrates” because they are slower to raise your blood sugar. But that’s exactly why someone with IBS or SIBO (small intestinal bacterial overload) should avoid slow carbohydrates. You should eat foods that will be easily and quickly absorbed. So if you have IBS, eat white bread, not whole grain bread, because whole grains have more fiber and therefore will feed the bacteria in your small intestine. Avoid whole grains.
6. Avoid beans. This includes soybeans. Avoid lentils, garbanzo beans, peas, etc. They all have indigestible fibers and sugars. You shouldn’t eat them if you have IBS or SIBO.
7. You can eat beef, poultry, fish and eggs. Those do not feed the bacteria in your small intestine.
8. Avoid alcohol. A study by Dr. Scott Gabbard indicates that alcoholic beverages may contribute to bacterial growth in the lower part of the small intestine. Read the study here.
9. Drink eight cups of water a day. You need enough fluid to produce good cleansing waves. Mark Pimentel, MD, the author of A New IBS Solution (which goes into detail about a perfect diet for IBS) suggests two cups of water with each meal, and then one cup between breakfast and lunch, and one cup between lunch and dinner.
10. Relax your body. Relaxation helps make the cleansing waves stronger. Tension and stress interfere with the digestion process. Relaxing helps everything work better.
Does this list surprise you? It surprised me. It sounds like the way everyone ate when I was a kid back in the 60’s — three “square meals” a day, no snacking in between, no artificial sugars, only one or two pieces of fruit a day, not many raw vegetables (but cooked vegetables), and white bread. Dinner was meat and potatoes and cooked veggies.
This is the diet for IBS if you want to feel better. Follow those ten guidelines and eat only three times a day, four or five hours apart, and you have a good chance of getting rid of your IBS for as long as you maintain the diet.
Of course, it’s possible this diet won’t work for you. If it doesn’t work, you may need a round of antibiotics first. Then follow the diet above. Some people need to kill off the bacteria in the lower part of the small intestine first, which is often done with rifaximin and/or neomycin — both of which stay primarily in the intestines (in other words, not much is absorbed into your blood stream).
Some people may require a prescription for a drug that stimulates the cleansing waves because their migrating motor complex has been damaged by the event that started their IBS in the first place.
For many people, their IBS started with a terrible bout of food poisoning or a parasitic infection. Sometimes, one of the results of the event is an impairment of the migrating motor complex. In other words, the poisoning or infection impaired their body’s ability to create cleansing waves. So now they don’t have strong cleansing waves. The indigestible foods don’t get washed into the colon very well, so they multiply where they shouldn’t be: In the lower part of the small intestine.
If your migrating motor complex has been damaged, you may need a prescription for a cleansing wave stimulator. Talk to your doctor about this.
In fact, it’s a good idea to talk to your doctor first (before you change your diet) in order rule out other causes of your IBS. Many other conditions can create IBS-like symptoms: Crohne’s Disease, colon cancer, celiac disease, etc., and these can be very serious. So see your doctor, take the tests, and make sure you really have IBS. If you do, follow the above diet for IBS. If it doesn’t do the trick, see your doctor for a round of antibiotics.
Another alternative to antibiotics, or something to use in addition to antibiotics, is two weeks of an “elemental diet,” which means only consuming Vivonex — a food formula with all the essential nutrients you need in a predigested form, which means the nutrients are absorbed quickly. This starves the bacteria in the lower part of your small intestine. You can read more about how that works in the book I mentioned above: A New IBS Solution. Treatment with antibiotics and/or Vivonex, followed by the diet for IBS, successfully eliminates IBS in 80 to 90 percent of patients.
So if you’ve ruled out serious diseases that may be masquerading as IBS or SIBO, try the diet for IBS above. If that doesn’t work, try a round of antibiotics and/or a couple weeks of Vivonex to kill off the bacteria first, and then follow the diet for IBS. And from now on, eat three meals a day, four or five hours apart, with nothing in between meals except water.
Adam Khan is the author of Principles For Personal Growth, Slotralogy, Antivirus For Your Mind, and co-author with Klassy Evans of How to Change the Way You Look at Things (in Plain English). Follow his podcast, The Adam Bomb.