Does The FODMAP Diet Reduce Gas and Bloating

Written by Dr. Steve Chaney on . Posted in Diets, FODMAP Diet, Gas and Bloating

Author: Dr. Stephen Chaney

 

fodmap dietCan the FODMAP diet help reduce gas, bloating, diarrhea, and constipation? Everyone suffers from one or more of these symptoms, but nobody talks about them. For some they represent an annoyance. For others they can be incapacitating.

When the symptoms become frequent and start to affect quality of life, the medical community starts to give them names. When the symptoms occur at least 3 days/month for at least 3 months and there are no known diseases causing the symptoms, it is called irritable bowel syndrome (IBS). If the symptoms are also associated with inflammation, it is called inflammatory bowel disease (IBD). The principle forms of IBD are Crohn’s disease and ulcerative colitis.

A Primer On IBS And IBD

IBS is fairly common. Between 10-15% of the US population has been diagnosed with IBS, but experts estimate that as much as 25% of the population experiences symptoms consistent with IBS.

It is also important to understand that IBS is a collection of symptoms, not a disease. The only difference between IBS and the gas, bloating, and diarrhea (or constipation) that many people experience on a fairly regular basis is the frequency and severity of symptoms – and that is an arbitrary distinction. Someone experiencing those symptoms an average of 2 days/month is not significantly different than someone experiencing those symptoms 3 times/month.

While severe IBS can be incapacitating, it does not appear to cause lasting damage to the intestine or predispose to other diseases. Finally, the causes of IBS are largely unknown. Stress, obesity, and food sensitivities may all play a role.

IBD is much less common (0.4% of the US population), but much more severe. It can cause permanent damage to the intestine and can predispose to several diseases, including cancer. For that reason, you should always consult with your physician if you have severe, chronic gastrointestinal issues.

Standard treatment of IBS and IBD has traditionally consisted of recommendations to:

  • Reduce weight if overweight
  • Increase exercise
  • Reduce stress
  • Limit caffeine and alcohol
  • Limit fatty foods
  • If diarrhea is the primary symptom, limit dairy products, fruits, and sweeteners such as sorbitol and xylitol.
  • If constipation is the primary symptom, increase dietary fiber

These interventions generally provide only partial relief of the symptoms, so medications are frequently prescribed to control the symptoms. Unfortunately, many of those medications have significant side effects.

Fortunately, research over the past decade suggests that there is a natural, holistic approach that can significantly reduce the symptoms associated with IBS and IBD, thus decreasing the reliance on medications to treat those diseases. It is something called the FODMAP diet. The FODMAP diet is rapidly becoming the standard of care for IBS and IBD, and the same diet also appears to significantly improve symptoms in people who merely experience gas, bloating, and diarrhea more frequently than they would like. More importantly, the principles behind the FODMAP diet can help almost everyone who experiences occasional gas, bloating, diarrhea and/or constipation.

What Is The FODMAP Diet?

The FODMAP diet was devised over a decade ago by a group of scientists in Australia. Basically, they identified all of the kinds of foods that were known to cause gas, bloating, diarrhea, and/or constipation in susceptible people and put together a diet that was low in all of them.

FODMAP is an acronym that stands for:

  • F – fermentable carbohydrates
  • O – oligo-saccharides
  • D – di-saccharides
  • M – mono-saccharides
  • P – polyols

Of course, that statement comes under the “Aren’t you glad you asked?” category. It is meaningless to most people. A better way to understand this is to look at foods in the FODMAP category. They include:

  • gas and bloatingLactose, found in milk and milk products (especially for people who lack the enzyme lactase)
  • Fructose in high concentrations, found in foods like apples, pears, honey and agave syrup. (30-40% of individuals have problems absorbing fructose).
  • Fructans, found in foods like wheat, onions and garlic.
  • Galacto-oligosaccharides, found in foods like beans, lentils, and soybeans.
  • Polyols such as sorbitol and mannitol, found in fruits such as cherries, apricots, and apples, and as sweeteners added to many “sugar-free” foods.

These are all foods that are poorly digested or poorly absorbed, so they are fermented by intestinal bacteria. It is the fermentation of these foods by intestinal bacteria that causes the gas, bloating, and diarrhea.

Does The FODMAP Diet Work?

The evidence that the FODMAP diet is effective is pretty impressive. For example:

What Does This Mean For You?

On the surface, this seems to be a good news, bad news story.

good news bad newsThe good news is that the FODMAP diet is incredibly effective at decreasing frequent gas, bloating, abdominal discomfort, diarrhea and constipation – and it really doesn’t matter whether you have been diagnosed with IBS or IBD, or you are just someone who suffers from those symptoms more frequently than you would like.

The bad news is that the FODMAP diet is very restrictive. You can appreciate that when you look at the list of high FODMAPs foods you need to avoid. That means:

  • The diet is very difficult to stick to long term. In the follow up study described above only 30% of the participants were able to stick with the diet for the full 16 months.
  • The diet restricts so many foods that you would really need the guidance of a registered dietitian to design a nutritionally adequate diet plan.

 

The reality, however,is that very few people actually need to restrict all the high FODMAP foods to enjoy significant relief from their symptoms. Clinically, most physicians test various FODMAPs in their IBS and IBD patients and only restrict the ones that cause symptoms. You can do exactly the same thing yourself. Start by reducing groups of high FODMAP foods on the list. Once you have identified which food groups cause your symptoms, you can test foods within that group one by one.

The most important news is that the FODMAP diet concept may help many people who struggle with occasional gas, bloating, and diarrhea. Let me give you one example:

  • Let’s suppose you have discovered that foods made from wheat flour cause you g.i. problems. You have concluded that you are gluten intolerant and carefully avoid foods containing gluten, but you still have occasional gas, bloating and diarrhea. You might be sensitive to the fructans in wheat, not the gluten. If so, a quick glance at the FODMAPs list suggests a number of fructan-containing foods you may be sensitive to that you would never have expected if you just focused on avoiding gluten. For example:
  • Vegetables: garlic, onions, asparagus, artichokes and snow peas might be causing you trouble.
  • Fruits: grapefruit, nectarines, plums and watermelon could be causing you problems.
  • Processed foods: Inulin, a naturally occurring fiber, found in Jerusalem artichokes, is primarily a fructan. Inulin and several other naturally occurring fructans are added to many processed foods to increase their fiber content. These foods might also be causing you trouble.

This is just the tip of the iceberg. Most of us have probably identified one or two problem foods that we know give us gas. By using the FODMAPs list we may be able to identify other foods we should avoid.

 

The Bottom Line

  • By restricting all foods known to cause gas, bloating, diarrhea and constipation in susceptible individuals, scientists and clinicians have created something called the FODMAP diet.
  • The FODMAP diet has proven to be very effective at reducing those symptoms in people with IBS or IBD, but it is also equally effective at eliminating symptoms in individuals who simply suffer from gas, bloating, abdominal pain, diarrhea and/or constipation more frequently than they would like.
  • The low FODMAP diet is also very restrictive, but the good news is that most people don’t need to eliminate all of the foods in the diet. You can systematically test and eliminate the individual foods that cause your symptoms.
  • Most importantly, the FODMAP concept can help us identify problem foods that we might have otherwise never suspected of giving us gas. You will find an example of how this concept works in the article above.
  • Gas, bloating, abdominal pain, diarrhea and constipation can also be caused by a number of serious diseases. For that reason, you should always consult with your physician if you have severe and chronic gastrointestinal issues.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Comments (2)

  • Nancy Pcsolyar, MA, DA, LDN

    |

    Thank you, Dr. Chaney. for addressing the FODMAP test. Little is written about it but yet the information is essential for people suffering from bloating, gas, etc.

    As always, your unbiased critique of various studies is priceless information especially for those of us working in the medical field .

    Reply

  • Anson Kibby

    |

    What an excellent article. Thank you SO much.

    Reply

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Latest Article

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

For more details read the article above.

 

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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