FODMAPs Can Affect People in Different Ways
Irritable Bowel Syndrome is very individualized and FODMAPs can affect people in different ways. FODMAPs are known to trigger symptoms in people with IBS. The onslaught of these symptoms can be uncomfortable, painful and adversely affect quality of life, however, all FODMAPs aren't necessarily "bad." Many FODMAPs are present in foods from the earth, which can provide our guts with needed nutrients, as well as probiotics and/or prebiotics.
From one person to the next, FODMAPs as well as stress, our bodies and health, and our environment can all play a role in symptoms, making everyone's experience different. For example, one person may have to completely avoid certain FODMAPs or just consume them in small quantities, while other FODMAPs may not present any gut issues. Also, one person may find some FODMAPs to not cause issues when consumed alone, but combined with other FODMAPs, an IBS attack is certain.
FODMAPs, The Good
Many FODMAPs are prebiotic in nature, meaning they are good for the gut and help to balance gut bacteria. Let's go over the benefits of FODMAPs and then discuss FODMAPs that may not be particularly nutritionally sound or useful for our guts, or how some people like to refer to them as "bad".
You've probably heard much about the benefits of probiotics and how the live bacteria and yeasts help keep your digestive system healthy. Maybe at some point you have taken a probiotic supplement. Fortunately with the low-FODMAP diet, there are a couple foods that contain probiotics such as: lactose-free yogurts and lactose-free kefirs with (live cultures), dark chocolate, tempeh, kimchi, sauerkraut or homemade pickles, and kombucha that are not made with high-FODMAPs. Kombucha is made when a culture is added to a sweetened tea. This sugary tea is then fermented with the help of a scoby. "SCOBY" is actually an acronym for "symbiotic culture of bacteria and yeast." Also, raw, unfiltered apple cider vinegar is not a probiotic but it's made with fermented apples, which contain pectin that can be good for digestion.
After you've completed the low-FODMAP diet, you may be able to enjoy some FODMAPs that are good for your gut as they contain prebiotics. As long as the following foods are not found to be triggering your symptoms of IBS, you can enjoy their prebiotic benefits: asparagus, garlic, onion, leeks, unripe bananas, barley, apples, as well as Jerusalem artichoke and chicory root which contain inulin, a FODMAP and form of prebiotic fiber.
According to new research, improving the growth of good bacteria and changing the biodiversity of the gut microbiome, may improve IBS and inflammatory bowel diseases (IBD). "Low gene count, or reduced microbial diversity, is found to be associated with an increased risk of inflammatory comorbidities and an increased tendency to overweight/obesity." 
Gut bacteria flourish on many foods containing FODMAPs. Gut microbes digest soluble fiber found in sources of fructans such as inulin or Fructo-oligosaccharides (FOS). Through this digestion, the biodiversity or variety of life within the gut habitat supports the gut flora, making way for a healthy ecosystem within the gut. Understanding your tolerance to FODMAPs and not staying on the diet for a long time means you will be supporting your body with a healthy diet. Consuming a wide variety of foods is one factor that plays a role in our overall health.
FODMAPs, The Ugly
Examples of FODMAPs that are not nutritious are high fructose corn syrup (HFCS), some Polyols and many processed foods that include high-FODMAPs such as cream sauces, other sauces, condiments, candies, cakes, crackers, cookies, frosting, ice cream, sodas, sports drinks and more.
HFCS is a Monosaccharide, is cheaper and sweeter than sugar, and found in so many processed foods. HFCS in the U.S. is among the sweeteners used by the food industry that are mostly replaced with sucrose (table sugar).
According to a couple studies by Princeton University in 2010, "on average, Americans consume 60 pounds of the sweetener (HFCS) per person every year." That statistic is no doubt higher today. According to Princeton's study and many other studies, HFCS can contribute to weight gain: "Rats with access to high-fructose corn syrup gained significantly more weight than those with access to table sugar, even when their overall caloric intake was the same." Eating too much high fructose corn syrup can also lead to insulin resistance, type 2 diabetes and high blood pressure and is thought to "cause hyperlipidemia (and possibly visceral obesity) because fructose is preferentially 'sent' to fatty acid synthesis and it also reduces the activity of lipoprotein lipase." 
Here are some foods and drinks you will avoid during the low-FODMAP diet as many contain HFCS – this is a short list so be sure to always read labels: applesauce, baked beans, breads, cakes, candies, canned fruit, cereals, cookies, condiments and sauces such as ketchup, A1 Steak Sauce, many brands of BBQ sauces, KRAFT Miracle Whip, pasta and cream sauces. HFCS can also be found in crackers, ice cream, jams, jellies, pickles, relish, syrups, tomato paste, chocolate drinks, fruit juices, soda, sports drinks. HFCS can also be found in cough syrups.
So you can see that if you're not already eating a whole foods diet how easy it is to consume HFCS!
Have you ever picked up a bag of sugar-free candies, gum or cough drops and viewed the warning on the back "Warning: May Cause Laxative Affect"? That would be the Polyols. Unless you have IBS and also need to manage blood glucose levels, are trying to lose weight or even prevent weight gain, you may not really need Polyols used in packaged products. Though Polyols occur naturally in many fruits and vegetables (such as apples, avocado, blackberries, lychee, cauliflower, mushrooms), they are also made by food manufacturers from starches, glucose, and sucrose, and are commonly added to foods.
Polyols are only partially digested and absorbed in the small intestine. Once they travel to the large intestine they can be fermented by bacteria. Symptoms from ingesting foods with Polyols include gas and flatulence, diarrhea, distention, bloating and more frequent bowel movements. Other non-digestible carbohydrates that can trigger fermentation and laxative effects are foods high in FODMAPs such as beans, onions, and prunes, other high-fiber foods as well as low-FODMAP foods such as cabbage and grapes.
On the low-FODMAP diet, avoid Polyols such as sorbitol, isomalt, maltitol, mannitol and xylitol. If you find after finishing the low-FODMAP diet you can tolerate Polyols, go ahead and have that avocado and enjoy "sugar-free" foods, but in moderation. The benefits of Polyols are that they do not cause sudden increases in blood sugar levels and do not promote tooth decay.
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 Chong MF, Fielding BA and Frayn KN. Mechanisms for the acute effect of fructose on postprandial lipemia. Am. J. Clin. Nutr. 2007 Jun;85(6):1511-20.
 Jim Laidler, MD, High Fructose Corn Syrup: Tasty Toxin or Slandered Sweetener? Sciencebasedmedicine.org, August 23, 2010.
 Bray, 2004 & U.S. Department of Agriculture, Economic Research Service, Sugar and Sweetener Yearbook series, Tables 50–52)
 Sugar Alcohols Fact Sheet, By Food Insight | Oct 14 2009