FODMAP fact drop

Most people have heard of the low FODMAP diet, but how well do we understand what it can help with and how it should be implemented? DFN's Queensland Lead Dietitian Emma Strutt APD distills the commonly misunderstood diet, providing the essential information. Article first published in Nourish Magazine.

A person feeling their stomach.

The low FODMAP diet is a three-phase dietary approach designed by researchers at Monash University, to help those with medically diagnosed irritable bowel syndrome (IBS) better manage their symptoms. Evidence suggests approximately 70–75 percent of people with IBS can experience symptoms from FODMAPs and following a low FODMAP diet can improve symptoms, especially bloating, abdominal pain, and diarrhoea. Some preliminary evidence suggests that limiting FODMAPs may also improve gut-related symptoms in those suffering endometriosis or inflammatory bowel disease, however more research is needed in this space.

What is a FODMAP anyway?

FODMAPs are certain types of carbohydrates that are poorly digested in the small intestine but are rapidly fermented by gut bacteria once they reach the large bowel. FODMAP is an acronym, which stands for:

  • Fermentable – carbohydrates that are broken down by gut bacteria.

  • Oligosaccharides – fructans and galactooligosaccharides, found in foods such as legumes, wheat, and onions.

  • Disaccharides – lactose, found in dairy products.

  • Monosaccharides – fructose, found in certain fruits and sweeteners such as high-fructose corn syrup.

  • And – no explanation needed for this one!

  • Polyols – sorbitol, mannitol, xylitol and maltitol, found in certain fruits, vegetables, and artificial sweeteners.

What's all the FODMAP fuss about?

FODMAPs generate gas and have an osmotic effect, meaning they draw water into the intestines to help with gut motility, which prevents constipation. While this is all generally part of a healthy functioning digestive system, these processes can result in digestive issues for some people with sensitive guts. However, this doesn’t mean high FODMAP foods are bad for our health.

It’s important you don’t avoid FODMAPs unnecessarily, as many FODMAP-containing foods are a valuable part of a healthy dietary pattern.

In fact, healthy gut bacteria thrive on many high FODMAP foods and the majority of people can include these foods in their diets without any ill consequences. It’s important you don’t avoid FODMAPs unnecessarily, as many FODMAP-containing foods are a valuable part of a healthy dietary pattern. A low FODMAP diet actually reduces the abundance of beneficial bifidobacteria in the gut, and if poorly designed, can also reduce intake of fibre and certain micronutrients like iron and calcium, all of which are very important for our long-term health.

Is the low FODMAP diet right for you?

We need to understand that FODMAPs themselves are not the cause of IBS, so eliminating them won’t cure the condition. Also, the low FODMAP diet was never designed to be a permanent change; rather it is a tool to help people identify which particular foods and FODMAPs trigger their symptoms, allowing them to adopt a more suitable eating pattern in the long term, whereby healthy FODMAP foods are gradually reintroduced, so that the gut can learn to love them. As gastroenterologist Dr Will Bulciewicz likes to say, we can think of this process in a similar way to strength training, where the gut is a muscle that is becoming stronger through careful, incremental increases in intake.

Depending on a person’s baseline diet and lifestyle, other changes such as exercise, altering fibre intake, or reducing treat foods could be a more suitable starting point than a low FODMAP diet. Some people may see improvements in their symptoms simply by including more whole plant foods, eating slowly, managing their stress, or moving more.

Trials have also found interventions like yoga and hypnotherapy to be just as effective as a low FODMAP diet for symptom management. Additionally, it’s worth noting that about 25 percent of IBS sufferers will not see improvements on a low FODMAP diet, so other therapies may need to be considered. When it has been determined that a low FODMAP diet is appropriate, there are three phases to move through:

  1. A two- to six-week elimination phase, where high FODMAP foods are swapped for low FODMAP alternatives.