What is Irritable Bowel Syndrome?

By Helaine Krasner, MS, RDN, CSOWM, CDN

Does an apple a day make you gassy and bloated? If the answer is yes, the culprit may be an irritable bowel. Irritable Bowel Syndrome, commonly referred to as IBS, is a common chronic condition that effects the stomach and intestinal tract. IBS is considered a functional digestive disorder and is not a disease. Typical symptoms include constipation, diarrhea, bloating, gas, cramps, and abdominal pain. Because these symptoms can also occur with other medical conditions it is important to seek medical attention to rule out another underlying cause. Self-diagnosis is not recommended and may result in failure to identify a serious medical issue.

Types of IBS presentation

IBS can be classified as either constipation predominant, diarrhea predominant, mixed – alternating constipation and diarrhea –  or unclassified – not fitting neatly into any category. The first step in getting relief is to identify contributing factors and manage symptoms. Age of onset tends to be below 50, and IBS is more commonly reported in females.

What causes IBS?

The exact cause is unknown. In IBS the normal contraction of the muscles in the intestines may not function properly resulting in spasms that can cause discomfort and either slow down or speed up the massage of food through the intestines. Discomfort may also stem from an oversensitivity of nerve endings in the digestive tract. Many experts attribute IBS to a disruption in the brain-gut axis, the system of communication between the brain and digestive tract. Risk factors include family history, stress/anxiety, food intolerance, or severe gastrointestinal infection.

Dietary treatment

A diet that reduces or eliminates certain carbohydrates can reduce symptoms in many people. Some types of carbohydrates are harder to digest and are more likely to undergo fermentation by gut bacteria and produce gas or draw water into the bowel. They are referred to as FODMAPs which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. These terms refer to the molecular structure of carbohydrates. In addition, some individuals may be sensitive to gluten, a type of protein found in wheat, barley, and rye. For them avoiding gluten may decrease IBS symptoms. Increasing dietary fiber from food sources or supplements gradually, allowing the digestive tract time to adjust, is another strategy that promotes bowel regularity and can improve IBS, but some types of fiber can also exacerbate symptoms.

It is important to try to identify if your symptoms are associated with consuming certain foods or beverages. Intolerance may vary day to day since the effects can depend on cumulative intake as well as other underlying contributing factors. Working with an experienced registered dietitian can simplify the process and help ensure a balanced diet that is well tolerated, without eliminating entire food groups unnecessarily. Following a complete low FODMAP diet is not usually necessary long term. The purpose of the diet is to remove foods temporarily that may be poorly tolerated to give the gut time to normalize and for symptoms to improve, typically two to four weeks. Then individual foods are reintroduced in a systematic fashion while tolerance is evaluated. Here is an example of foods from different food groups that are either high or low in FODMAPs.


Food Group High in FODMAPs Low in FODMAPs
Protein Beans, lentils, processed meats Seafood, poultry, meats, eggs
Grains Wheat, barley, rye products Oats, rice, corn
Dairy Milk, yogurt Feta, hard cheeses
Fruit Apples, watermelon, pears, peaches Oranges, grapes, strawberries, pineapple
Vegetable Cauliflower, asparagus, garlic, onion Tomato, carrots, zucchini, cucumber
Sweeteners Honey, high fructose corn syrup Sugar, maple syrup


Other lifestyle strategies to manage IBS and decrease frequency of flare-ups include stress management, regular physical activity, limiting intake of highly processed foods, eating smaller more frequent meals, staying hydrated, and getting adequate sleep. In more severe cases medications may be prescribed.


  • Work with a registered dietitian to help you reduce symptoms while also consuming a balanced diet
  • Aim for five to six small meals/snacks daily
  • Aim for 20-35 grams of fiber daily, and consider a psyllium fiber supplement
  • Aim for six to eight cups water daily
  • Prioritize stress management and sleep



Irritable bowel syndrome – Symptoms and causes – Mayo Clinic

Low Fodmap Diet: What it Is, Uses & How to Follow (clevelandclinic.org)


Helaine Krasner, MS, RDN, CSOWM, CDN is a registered dietitian nutritionist who takes great pride in helping our Bariatric and Medical Weight Management patients achieve their health and weight loss goals.