Low FODMAP diet – what to eat, what to avoid, meal plans and sample recipes

What will you learn from the article?

FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols), or fermentable oligosaccharides, disaccharides, monosaccharides and polyols, are a group of foods that ferment easily, are poorly absorbed and increase osmotic pressure. The FODMAP-restrictive diet was developed by Australian researchers at Monash University as a therapy to alleviate symptoms of irritable bowel syndrome (IBS).

The hypothesis of FODMAPs was first published in 2005 as a major cause of Crohn’s disease development [1]. The theory was based on the fact that the increased intake of FODMAPs, typical of the modern Western-type diet, and their subsequent rapid fermentation in the large intestine contributes to increased intestinal permeability (so-called leaky gut syndrome), resulting in the development of the disease in individuals with a genetic predisposition.

What are FODMAPs?

So let’s decode whether FODMAPs are and where they can be found. A FODMAP is made up of five main components:

Fructose – is available in the diet as a free monosaccharide, as a component of disaccharides (including sucrose) and in a polymerised form in fructans. When fructose is consumed as sucrose or in similar amounts to glucose, fructose absorption is estimated to be 85 %. When the amount of fructose far exceeds that of glucose, the absorption of this sugar is impaired. Furthermore, approximately 30 % of the population is unable to absorb fructose in its free form [1].

Fructans – are a group of compounds containing fructose polymers with a glucose molecule at the end of the chain. Depending on the number of fructose molecules, we distinguish between oligosaccharides (2 – 10 molecules) and polysaccharides (> 10 molecules). Typical examples of fructans are fructooligosaccharides (FOS) and inulin, which are classified as prebiotics. The prebiotic effect is due to the fact that fructans are not digested in the small intestine and enter the large intestine intact [2]. There, they can feed the intestinal microbiota, which can benefit its development, but also contribute to increased gas production and bloating.

Lactose – a milk sugar that is only digested in the small intestine in the presence of the enzyme lactase. Deficiency of this enzyme occurs to varying degrees in different countries and ethnic groups. The deficiency of this enzyme is estimated, for example, at 2 % in Scandinavia, while in Asian countries it can exceed 90 % [1]. Importantly, the amount of lactase decreases with age, which can cause problems with lactase digestion in old age

Polyols – a.k.a. polyols with a sweet taste, which is why they are often used as less calorific sugar substitutes. Polyols include sorbitol, xylitol, mannitol and maltitol. Polyols occur naturally in fruit. They are poorly absorbed in the small intestine and are fermented very quickly.

Galacto-oligosaccharides (GOS) – are oligosaccharides consisting of galactose molecules terminated by glucose. As with FOS, the chain length of GOS can range from 2 to 8 molecules and GOS are also classified as prebiotic products. Humans do not produce the enzyme that allows the breakdown of GOS, namely α-galactosidase, which is produced by intestinal bacteria. Legumes are a rich source of GOS. The way to reduce the level of GOS in legumes is to heat-treat them.

What products contain FODMAPs?

Fructose:

• Fructose-rich fruits, e.g. peaches, mangoes, apples, watermelon, cherries and pears
• Products containing glucose-fructose syrup, e.g. sweets, sweetened yoghurts, canned fruit, processed foods
• Sweeteners, e.g. sucralose and saccharin

Fructans:

• Wheat and rice products
• Products rich in inulin, such as Jerusalem artichoke and chicory
• Onions
• Garlic
• Asparagus
• Artichokes
• Broccoli
• Brussels sprouts
• Beetroot

Lactose:

• Cow’s milk
• Dairy products including yoghurt, ice cream (not sorbets), certain types of cheese such as mascarpone, ricotta, country cheese

Polyols:

• Cauliflower,
• Mushrooms
• Sweeteners ending in -ol
• Chewing gum
• Fruits, e.g. pears, apples, plums, nactarines, watermelon and others

GOS:

• Asparagus
• Beetroot
• Onions
• Garlic
• Leek
• Wheat

When to follow the low fodmap diet?

We now know that FODMAP intolerance is more common than just inflammatory bowel disease. FODMAP intolerance or hypersensitivity is common, and this diet is also recommended for people with small intestinal bacterial overgrowth (SIBO). Interestingly, a diet high in FODMAPs is one that is usually considered healthy – rich in whole grains, vegetables and fruit. Why are some people sensitive to FODMAPs and others not? This is due to limited production of certain enzymes needed to digest certain food components. For example, if we know that we have a deficiency of the enzyme lactase, we can take it orally during a meal that contains lactose.

What are the symptoms of FODMAP intolerance?

The problem with FODMAPs is what lies behind the letter F in the acronym, which stands for fermentable. Fermentation produces gases, including hydrogen, carbon dioxide and methane, which accumulate in the gut. In addition, FODMAP has an osmotic effect, which means that it draws water into the cells surrounding the colon. As a result, the stool produced in the bowel is more diluted and the bowel contents increase in volume. Typical symptoms of FODMAP intolerance include

• flatulence
• gas
• discomfort
• a feeling of overflowing
• abdominal pains
• constipation or diarrhoea

What do the 3 phases of the Low FODMAP Diet look like?

The FODMAP-restrictive diet is not about eliminating FODMAPs altogether, but about limiting the amount of products containing FODMAPs. The low-FODMAP diet consists of three phases [3]:

• Phase 1 – reduce FODMAPs and replace products with ones that contain much less of them. Lasts 2 – 6 weeks until symptoms resolve. If symptoms do not resolve, it means that maybe FODMAP is not the problem.
• Phase 2 – reintroduction. The low-FODMAP diet is continued, but one FODMAP-rich product at a time is introduced and ‘tested’ for 3 days to see if it causes adverse symptoms. For each product, the portion size is also increased to determine the ‘tolerable dose’. This phase lasts between 8 and 12 weeks.
• Phase 3 – personalisation. In this phase, products tolerated in phase 2 are introduced into the diet, while symptom-causing products are reduced to a tolerable amount. This diet is maintained. It is recommended to re-test from time to time whether the symptom-causing products continue to cause hypersensitivity.

Which products are low FODMAP?

• Fruit: raspberries, strawberries, citrus fruit (mandarins, oranges, lemons, limes) grapes, kiwi, passion fruit, banana (unripe)
• Vegetables: potatoes, peppers, cabbage (except Italian cabbage), tomatoes, olives, lettuce
• Mushrooms: oyster mushrooms, mun mushrooms, marinated mushrooms
• Cereal products: buckwheat, millet, oat, quinoa, rice
• Dairy products: lactose-free products, renneted cheeses (yellow, parmesan, brie, camembert, feta, mozzarella)
• Legumes: tempeh, cooked lentils
• Meat, fish, eggs
• Nuts: walnuts, pecans, Brazil nuts, macadamia nuts
• Herbs and spices (except those containing garlic and onions)
• Fats
• Sweeteners: sugar, glucose, maple syrup, stevia

Importantly, many foods can contain both high and low levels of FODMAPs depending on ripeness or processing. For example, an unripe banana can be eaten, but the more ripe it is, the more FODMAP levels increase. Cooking in water can lower levels of FODMAPs, which are mostly water-soluble and permeate the broth. Fermentation can reduce the levels of FOS and GOS, which are excellent nutrients for fermenting microorganisms [4].

Low Fodmap Diet sample menus and recipes

When starting a low FODMAP diet, the key is to plan meals that are not only in line with the diet guidelines, but also tasty and satisfying. We present a sample two-day menu to help you understand how you can incorporate the low FODMAP diet into your daily life. These examples of breakfasts, lunches and dinners are chosen to provide a variety of flavours and textures, while still adhering to the restrictions of the diet. From the freshness of avocado at breakfast to the richness of flavours at dinner, these meals are designed to show that a low FODMAP diet can not only be effective, but also pleasing to the palate.

Meal plan day 1

• Breakfast – slice of sourdough bread, half an avocado, fried egg
• Lunch – baked salmon with tomatoes, brown rice, cucumber and lactose-free yoghurt misoise
• Dinner – salad with chicken, iceberg lettuce, parmesan, olives and tomato with olive oil dressing

Meal plan day 2

• Breakfast – oatmeal on lactose-free milk with peanut butter, raspberries and cinnamon
• Lunch – vegetable frittata with eggs, yam, courgette and parmesan cheese
• Dinner – grilled beef steak with roast potatoes and cooked broccoli

What is the difference between a low FODMAP diet and a ketogenic diet?

FODMAPs are mostly carbohydrates, which are also eliminated in the ketogenic diet, so both types of diet eliminate grains, most fruits and starchy vegetables. However, the purpose of these diets is quite different and there are groups of products that differ in their effects. For example, dairy products, which are commonly used in the ketogenic diet, can exacerbate intolerance symptoms. On the other hand, a low-FODMAP diet can include buckwheat and rice products, which do not maintain ketosis. The keto diet can be balanced to limit FODMAPs if they cause intolerance. It is then a very eliminationist diet, so it is better to consult a specialist nutritionist to avoid nutritional deficiencies.

What does a reduced FODMAP ketogenic diet look like?

The combination of a ketogenic diet and a low-FODMAP diet can be a good choice when, in addition to FODMAP intolerance, the aim of the diet is to lose weight or improve blood sugar control. This diet combines the principles of both diets, namely limiting carbohydrates and FODMAP-rich foods. Contrary to appearances, this diet contains a lot of allowed products such as:

• Meat – beef, chicken, turkey, pork including bacon, lamb, duck
• Fish – tuna, salmon, other oily fish, shellfish
• Eggs
• Cheeses – cheddar, gouda, feta, mozzarella, parmesan
• Vegetables – spinach, cucumbers, red peppers, turnips, lettuce, celery, broccoli, tomatoes, courgettes and many more
• Berry fruits
• Avocados
• Plant-based drinks – unsweetened almond drink, macadamia nut milk
• Nuts and seeds – Brazil nuts, macadamia nuts, peanuts, pecans, pine nuts, walnuts, chia seeds, pumpkin seeds, flaxseed

Is there a Risk of a reduced FODMAP ketogenic diet?

It may not always be a good idea to combine a ketogenic diet with a low FODMAP diet. In people with IBS, an increase in fat, especially saturated fat, may worsen gastrointestinal symptoms. In addition, following two elimination diets at the same time may increase the risk of nutrient deficiencies. To date, no scientific studies have been conducted on the safety and potential health benefits of a low FODMAP ketogenic diet.

Summary

The low-FODMAP diet appears to be an important tool for managing and relieving the symptoms of irritable bowel syndrome and other digestive disorders. Its effectiveness, based on limiting the consumption of certain carbohydrates that can trigger digestive problems, has been confirmed in several studies. Through the appropriate elimination and reintroduction of products, this diet offers an individualised approach to each patient, enabling them to find a balanced diet that minimises intestinal discomfort.

However, it is important to note that the low FODMAP diet is not suitable for everyone. It requires careful planning and adherence, often involving consultation with a dietician or other specialist. It is important to emphasise the role of the specialist in introducing and monitoring the diet to ensure that it is safe, balanced and tailored to the individual’s needs.

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Bilbiography