Surviving a low-FODMAP diet

For anyone over 50, nothing compares to the dread induced by a doctor who declares “It is time for a colonoscopy.” The procedure is bad enough, particularly for a modest person. Thank goodness it all happens when we are asleep! The real dread comes, however, the day before the “procedure” when purging the guts of all of its waste is our prime mission—certainly not my idea of a good time.

My colonoscopy was actually a year ahead of the normal schedule. I had observed some changes in my bowel movements. I will spare you the details of my symptoms. Suffice it to say that they were of sufficient concern to me to voluntarily go through the trauma early. This event was the fourth that I have completed in my lifetime, and I noted some differences from my earlier experiences. I was particularly amazed at all the disposable plastic tubing that I observed in the setup just after being wheeled into the operating theater and before I passed out. Also, I observed that there were many medical professionals involved in the process, all of whom seemed interested in giving me the proper care I desired.

It just so happened that as I was emerging from the cloud of anesthesia my wife had left the room for a restroom break. The gastroenterologist who had performed the procedure informed me that they had found and eliminated some polyps. He gave me some pretty pictures for my scrapbook and told me that he wanted me to try a new diet. He also indicated that I will have the opportunity to be screened again in five years. That will probably be my last one as they rarely scope out people older than 75. By the time my wife returned, the nurse had pulled out a sheet of paper she had scanned from the internet on the low FODMAP diet. The nurse asked if I ate many dairy products. I said that I did, and she said that the dairy foods might be my problem. Then we left the hospital and went across the street to break my fast with a big meal of eggs and hashbrowns but no dairy. It was only later that I read the doctor’s orders suggesting that I not eat big meals for several hours after my procedure.

What is FODMAP?

  • F is for Fermentable
  • O is for Oligosaccharides (in wheat and in spices)
  • D is for Disaccharides (lactose)
  • M is for Monosaccharides (fructose)
  • A is for and, and
  • P is for Polyols (sorbitol and mannitol)

Put it all together and it spells out an extremely restrictive diet designed to eliminate all the FODMAPs in the diet. The general theory behind the diet is that certain chemicals from our foods reside in our gut and can be fermented by the microbes that inhabit it resulting in objectionable actions collectively known as IBS—Irritable Bowel Syndrome. There appears to be a wide variation in manifestations of the disorder and individual susceptibility. Symptoms can include abdominal pain, bloating, constipation followed by diarrhea, obnoxious gas emanations, and an urgent need to defecate. Most of the FODMAPs are components of whole foods. The additives in processed foods in this class are high fructose corn syrup and the polyols. Fructose is also a primary component of honey, grapes and other fruits. Polyols are also natural components of many whole fruits such as apples and blueberries as well as whole vegetables such as avocado and sweet potato.

To eliminate all foods containing FODMAPs would leave the dieter with very little to eat. Thus, the recommended diet suggests small quantities of certain foods like ½ cup of berries or most other fruits, ½ cup of many vegetables including onions and green beans, and 2 tablespoons of peanuts or almonds. Foods with little or no FODMAPs include eggs, meats, hard cheeses, potatoes, and carrots. Yes, I know that cheese is a dairy product, but hard cheeses are the curds in the cheese-making process. The whey is skimmed off these curds, and it is the whey that carries the lactose.

Starting out. As a food scientist I had the advantage of a good knowledge of food composition. From my years as an instructor of Food Chemistry I was familiar with all the FODMAP terms. I actually had read about the diet previously, but knew little about it and had no clue that I would eventually be on one. I went on the internet, but recommendations were confusing and contradictory. I went to and found two books on the topic by RDs—The Low-FODMAP 6-Week Plan & Cookbook and The IBS Elimination Diet and Cookbook. I developed a diet plan from the second book as it seemed more relevant to my needs than the first one.

Patsy Castos, MS, RDN, LN provided a very nice set of dietary plans with a few useable recipes, including Traffic Light Chili, the one that made a hit with my wife. The author also provided an aggressive plan, a more modest option and a shortcut. I opted for the aggressive plan. My concerns going into the diet were that it

  • would be difficult for me to maintain my weight
  • called for many foods that contained saturated fats such as eggs, meat and cheese, and
  • cut out fiber with only small amounts of fruit, not many vegetables and no whole grain cereal containing wheat.
gluten-free everything bagels and gluten-free bread
Gluten-free options

Methods. I went through a seven-week trial. The first two weeks I eliminated high-FODMAP foods with allowances for small amounts of certain foods that contain FODMAPs. Without them, the diet would be sparse indeed. Challenges began on Tuesday of the third week on which I had a ¼ cup of onions as a representative food from Oligosaccharides not associated with gluten. The next day I had a cup of oatmeal, ¼ cup of raisins, ½ cup of cashews, 2 teaspoons of garlic and ½ cup of black beans. Then I waited not-so-patiently and observed any evidence from my bowel movements over the next five days.

On the following Tuesday, I started all over again challenging my digestive tract with the Disaccharide lactose. I repeated the process on subsequent Tuesdays for the Polyol sorbitol, the Polyol mannitol, and the Oligosaccharides associated with gluten. I did not challenge with the Monosaccharide fructose as I have been very careful for the last 30 years not to overconsume sugars such as fructose and sucrose to prevent the progression of a diagnosis of prediabetes to full-blown diabetes.

lactose-free milk, cottage cheese and chocolate ice cream
Lactose-free options

Results. It became apparent early in the process that a low-FODMAP diet is not a great one to be on. Some of the food is enjoyable, but much of the good stuff is limited to small amounts. I noticed a loss of weight over the weeks, which was a good thing for the first five pounds which I wanted to lose earlier. Unfortunately, I kept losing weight, bottoming out at eight pounds.

The biggest frustration in my low-FODMAP diet experience was that none of the challenges proved conclusive. I did observe some moderate symptoms with wheat-associated Oligosaccharides and with the Disaccharide lactose. All other FODMAPs led to either only mild or no symptoms. Elimination of lactose from my diet was still not sufficient. Even just one bagel, four slices of pizza or a single hamburger over a week elicited an undesirable response. Currently, I am avoiding lactose and gluten to see if I can stabilize my gut. On the positive side, despite greater consumption of fats, particularly saturated fats and less dietary fiber, my blood lipids and other blood values are within the standard range.

cheeseburger without a bun, crinkle-cut fries and mayo for dipping
Gluten-free fast food meal

Discussion. I confess to being disappointed that the program did not provide definitive answers. It is now fifteen weeks since my colonoscopy, and I would like to move on with my diet and my life. With the miracle of processed, lactose-free dairy products, I can have my milk and associated products without consequences. I note that nondairy offshoots of these products are not nearly as good as the real thing and tend to mold soon after they are opened.

Giving up bagels, sandwiches, pizza and whole-wheat breakfast cereal is much harder. Gluten-free bread makes good, dense toast but is not great for sandwiches. Gluten-free bagels are too dense for my purposes. I haven’t tried gluten-free hamburgers or pizza yet, but my expectations are not great. I have yet to find a whole grain cereal with at least 10 grams of fiber that is not wheat based. Fortunately, I can still enjoy beer. Gluten-free breads have long shelf lives when frozen, but they mold in less than a week at room temperature. I have much more empathy for my niece and anyone else who is also gluten-free.

Arepas--grilled cornwich, sweet corn & mozzarella
Gluten-free, lactose-free meal at NASCAR race

I must admit I am enjoying eating more beef, cheese, eggs and fries than I did before I started worrying about FODMAPs. I am eating out less, eating about the same amount of processed foods and trying to reincorporate more fruits and vegetables back into my diet. I have gained back the three pounds I didn’t want to lose and am happy with my current BMI of 22.7. Watch this space for updates on my diet.

Next week: Celebrating 70 years of eating


18 thoughts on “Surviving a low-FODMAP diet

  1. That being said it isn’t the worst thing in the world,now it makes me more determined to become a food scientist & work in the development of special foods for those with IBS or food sensitivities… Having been through it I understand how devastating it can be when one has these issues let alone when one manufacturer stops making the only gluten free bread you can eat,,that I would keep in case of emergencies,for taking to the hospital when they literally had nothing I could eat at the hospital ER & my blood sugar was extremely low…When traveling you have to bring food in your suitcase because your main ingredient is not available in the other country you’re flying to or find a big supermarket far away or you have to call up & book your ingredients at the supermarket to make sure they order & put aside enough so you can eat during the week…


    1. We would love to have you in a food science program. Please contact me directly at if you would like some guidance in choosing a program. I would highly recommend “Future Foods” by Julian McClements who, I am afraid, is much more woke than I am. I will be reviewing his book on my site in either December or January.


    2. “I have been very careful for the last 30 years not to overconsume sugars such as fructose and sucrose to prevent the progression of a diagnosis of prediabetes to full-blown diabetes.”


      Sugar doesn’t cause diabetes.


      1. That is true, but diabetes leads to an inability to control blood sugar levels. There are three ways to control blood sugar levels: insulin injection, medications, and diet. The current measure to distinguish between a nondiabetic state, prediabetes, and diabetes is the a1C test. I was diagnosed with prediabetes (called chemical diabetes then) in the mid-1980s based on my fasted blood glucose and a two-hour postprandial test (a1C tests had not been developed yet). My diabetes has been under control since then as my a1Cs have ranged from 5.5 (nondiabetic) to 6.0 (prediabetic) for 30 years. My physicians have not known anyone who has maintained that state for that long. My eye tests have not shown any evidence of damage. If you know of contrary information, please let me know. If you have sources, I would love to read them. Thank you.


  2. Hope your gut gets better soon! Have been on vegan low FODMAP diet & it was a giant pain (with added food sensitivities because that wasn’t restricting enough!) I never got beyond the re-introduction phase for years because that would cause massive amounts of pain,so I was stuck day in & day out eating the exact same things at almost every meal.Lost lots of weight because the diet got very boring very quick.I even asked a chef to help me find ways to make my diet more interesting by listing the foods I could eat,they were stuck for ideas except for char grilling vegetables which I don’t like or eating flowers.

    Eventually I got better.I would suggest you look into modernist cuisine & see if some of the “new” cooking methods,ingredients & processes can help vary your diet.If you have the money & access to buy foreign (dried) foods in which you can get a rough idea of the FODMAPS they contain/test them out that could help.If you can induce the placebo effect that tends to help with IBS .A strong placebo response is what got me better & allowed me to have a way more varied diet now.In terms of getting rid of IBS I’m guessing you’re already looking into the latest medical research… maybe you have a specialist that has been reading up on the latest studies that you can book an appointment with…?
    Get well soon! & courage during the Christmas season


    1. Thank you for your suggestions. I seem to be doing better in the last week or two. It is a real challenge, particularly when there are not definitive signs to see if the diet is in compliance. I can only imagine how difficult combining a lowFODMAP diet with a vegan diet would be. At least one of the books I read on the topic essentially indicated that the two are NOT compatible.


      1. Glad you are doing better 🙂
        They are not so compatible,but possible to do
        Yes there are lists which seem to contradict each other,I was given one by my nutritionist & saw some online that said some low FODMAP foods should be avoided,so it may depend on where the food is grown.I know for the Nordic countries the sugar content of carrots can change due to the climate,the many hours of sunshine in the summer & the cold of the winter make the carrots differ.


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