irritable bowel syndrome

Bloating? Gas? It Could be your Diet


Everyone of us will suffer excess gas, bloating or noisy stomach at some point in our lives. But for some, this is a constant problem that can cause embarrassment or discomfort. Typically, the diet is the primary cause – but there are signs and symptoms to be mindful of.

If you suffer from a condition called irritable bowel syndrome (IBS) or simply have gut symptoms that bother you from time to time, you might want to look at your diet.

This article looks at food culprits that can cause any of the following symptoms:

  • Bloating
  • Excess gas (flatulence)
  • Diarrhoea
  • Borborygmi (gurgling noises in the gut)

When to Worry

It could be too easy to ignore symptoms associated with our gut, but by doing so, we could be putting our health at risk.

It’s always worth checking with a doctor first before changing your diet to ensure that it is food that’s causing the issue, and not something else.

The following symptoms should never be ignored, however:

  • Passing blood when you go to the toilet
  • Prolonged extreme fatigue or tiredness, despite sleeping well
  • Losing weight unintentionally
  • Loss of appetite
  • Pain or cramping in the stomach area
  • Persistent diarrhoea

It’s more likely that you’ll be diagnosed with irritable bowel syndrome than not, but that’s no reason not to check it out. Don’t let your friends or internet articles be your source of medical advice.

Main Problematic Foods

The following foods are all part of a larger group of foods called FODMAPs, which is an acronym for the more sciencey terms: fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.

Basically,  types of carbohydrates that ferment in the gut, releasing gas; usually through the action of bacteria that live there.

This is a large list – there is no way anyone could (or should) go through this list and eliminate every single food. You would have nothing to eat and could run into other health problems.

It’s very unlikely that you’d be intolerant to every single food item, but the one you are is probably in this list somewhere!

Try and not allow more than 3-4 weeks on a low FODMAP diet before you start to re-introduce potentially problematic foods. Doing so could mean following an unnecessarily restrictive diet.

As soon as you experience symptoms, stop that food and allow another few weeks and introduce another. Eventually you’ll know the foods that cause problems and those that don’t.

Once you’ve identified the problem foods, wait a while and sneak them back in a small amount at at time, giving your body time to adjust. With luck, you’ll be back onto a normal diet – but be patient – this can take months!

Use this as a guide only, along with a qualified nutrition professional, to help you identify foods that could be at the crux of your gut problems.

If you have a definite diagnosis of IBS, and would like some help with your diet, I’ll include some great resources at the end for what is known as a low FODMAP diet.


Oligosaccharides are carbohydrates that we’re unable to digest because humans lack the enzymes to break them down.

They therefore reach the large gut in an unprocessed state, but the beneficial bacteria that live in the colon think that’s great – because for them, this is lunch.

There are two main oligosaccharides that could be causing us some issue:

  • FOS – or fructo-oligosaccharides
  • GOS – or galacto-oligosaccharides

FOS are found in the onion family such as leeks, onions, garlic, as well as Jerusalem artichokes and asparagus.

GOS are found in beans, lentils, peas and other legumes. They’re also present in the cabbage family.

These are very important carbohydrates in our diet, because they’re high in soluble fibre, which helps prevent constipation and keeps everything moving.

They also promote the growth of beneficial bacteria and are therefore known as prebiotic foods.

The flip side to this is, if you eat too much, you could experience bloating, pain, diarrhoea and a lot of gas.

This may also be one of the reasons for borborygmi (gurgling noises), as so much gas is produced, it’s not being absorbed quick enough by the body.

So have a look at your diet and consider whether you’re overloading your body with the following foods. If so, consider decreasing the portion sizes and see how that helps.

FOS Foods GOS Foods
Onions, onion powder Jerusalem artichoke
Garlic Lentils
Chicory root Beans
Jerusalem artichoke Soya milk (depends on production method)
Globe artichokes Peas
Asparagus Chickpeas
Leeks Broccoli
Banana Beetroot
Yacon Onions
Dandelion leaves Fennel
Camas bulb Rye, wheat, barley
Barley Cabbage

Digestive enzymes

There is some evidence that using digestive enzyme supplements could help mitigate the effects of FODMAPs, particularly those associated with galactose and fructose.

However, there’s not enough science to categorically state that digestive enzymes are effective in everyone, but they’re certainly worth a go if you have an understanding of which foods are more difficult for you to tolerate.

Digestive enzymes can be bought in most health food stores.

Ingredients List

When you’re buying foods, you might want to look out for the following in the ingredients list (most are thickening agents):

Starch, modified starches, dextrins, maltodextrins, chondroitin sulfate, maltotriose, raffinose, stachyose, verbascose, mannan oligosaccharides, isomalto-oligosaccharides, agar agar, acacia gum, algin alginate, arabynoxylan, beta-glucan, beta mannan, carageenam gum, carob or locust bean gum, fenugreek gum, pectin, guar gum, inulin, tara gum, psyllium husk mucilage, resistant starch, xanthan gum, cellulose, chitin/chitosan

If you eat a lot of processed foods, you could find that your symptoms disappear if you eat your own home-cooked foods without all these additives.


The next culprit could be disaccharides. These are foods with much more simple carbohydrates than oligosaccharides.

The clue is in the stem di, meaning two. These carbohydrates contain only two types of sugar, such as sucrose (common table sugar) – which is a blend of glucose and fructose.

Foods that contain high sucrose may not breakdown if we’re lacking the enzyme sucrase.

We therefore might find some fruits, and sweetened products like sweets and cakes cause symptoms – typically diarrhoea and excess gas.

Lactose is another, and so people with intolerance to milk could also suffer these symptoms. Milk requires an enzyme called lactase in order to process milk and milk-based products.

Some dairy products have more lactose than others, and so people with disaccharide intolerance might find that milk is a big problem but not certain types of cheese or strained, Greek yoghurt.

Any yoghurt that has a lot of the whey removed may be lower in lactose, and some aged cheeses are also low in lactose too.

However,  any product that is fermented such as kefir and live yoghurts will also have reduced lactose, because the bacteria degrade the sugars to make lactic acid – which gives fermented milk products a distinct sourness.

But the flip-side to this is that manufacturers may introduce sugar to counteract that. So look at the ingredients.

Lactose intolerance basically means that only low amounts of lactose can be tolerated, and it means experimentation to find where that low level is.

Maltose is also a disaccharide, and needs maltase or isomaltase to break it down in the gut. Maltase is found in grains and starchy vegetables.

The following foods are problem foods for people who struggle to properly digest disaccharides, and it might be necessary to eliminate them all to begin with and introduce them group at a time.

Foods high in lactose Foods high in sucrose Foods high in Maltose
Milk Table sugar Barley
Cheese with the exception of aged cheeses like Swiss cheese and parmesan Biscuits, cakes, sweets, sweet pastries, sweet buns Gluten-free bread, crackers, rolls
Butter and margarine made with milk solids or whey Chocolate Sweet potato
Sweetened yoghurts and milkshakes Breakfast cereal, cereal bars and flapjacks Processed foods such as tinned foods and jarred sauces, ketchups, salad dressings, mayonnaise and many other condiments
Processed foods/ready meals that have any of the following in the ingredient list: milk solids, whey/whey powder, casein Processed foods such as tinned foods and jarred sauces, ketchups, salad dressings, mayonnaise and many other condiments Breakfast cereal, cereal bars and flapjacks


If di is disaccharides means two, mono in monosaccharides means one. These are the simplest sugars of all. They include: fructose, glucose and galactose.

The human body attempts to break down all carbohydrates into glucose as that’s the preferred energy source.

We store glucose in the body via a process in the liver that converts excess glucose into glycogen or body fat.

If we consume foods high in any of these simple sugars, our blood sugar will rise quickly with the exception of fructose.

Fructose is slightly unusual, it finds its way  into the body through its own unique mechanism. It has the sweetest taste, and therefore is a favourite to add during manufacturing.

Fructose can cause some people to suffer diarrhoea and borborygmi

The safest fruits are berry fruits like: strawberries, blueberries, raspberries, and blackberries

The worst are stone fruits such as: cherries, plums, peaches, apricots, nectarines, dates, mango.

Watermelon and grapes may be troublesome as are orchard fruits such as pears and apples.


Polyols are sometimes referred to as sugar alcohols, and are not carbohydrates in the same way as all the other FODMAPs.

They are derivatives from sugars such as lactose or maltose, which are processed in order to retain the sweetness but without the calories.

They are therefore frequently used as artificial sweeteners in many foods in order to replace the sugar to keep the taste, but reduce the calories.

They’re also used in products that we don’t eat, but need a pleasing taste such as: toothpaste, mouthwash, chewing gum.

However, polyols are often used in combination with other sweeteners because their overall sweetness is lower than sugar.

It’s been known for a while that polyols can have a laxative effect, and so many low calorie sweets that use artificial sweeteners carry a warning that eating too much could cause diarrhoea.

There is quite a long list of polyols, but here are the main ones you may find in the ingredient list of the foods you find in your supermarket:

  • Glycerol
  • Inositol
  • Isomalt
  • Lactitol
  • Mannitol
  • Xylitol
  • Erythritol
  • Hydrogenated starch
  • Maltitol
  • Sorbitol

And they may be found in the following sweeteners:

  • Aspartame
  • Stevia
  • Saccharin
  • Sucralose
  • Acesulfame potassium

Polyols also exist naturally in some foods (sorbitol, mannitol and xylitol) such as:

  • Beans
  • Beetroot
  • Brocolli
  • Brussel sprouts
  • Cabbage
  • Carrots
  • Cauliflower
  • Celery leaves
  • Mushrooms
  • Peas

Safe Foods

The following foods are low in FODMAPs. Eating these foods usually does not cause symptoms, although some of the listed fruits might! In my experience, whilst pineapple, grapes and melon are often listed as “safe foods” – they can and do cause bloating and gas.

But, it’s often portion-related! Small amounts are usually OK. If you binge, you may hit trouble.

However, as ever, discuss with your clinical nutritionist first.

Fruit Vegetables Nuts/seeds Dairy Other
Blueberries Avocado Almonds Lactose-free milk Tofu
Citrus fruit: oranges, grapefruit, lemon,lime Bamboo shoots, ginger, galangal Brazil nuts Lactose-free cream Tempeh
Coconut Bok choy, Collards, endive, kale, rocket (arugula), spinach Chestnuts Lactose-free cream cheese Coconut milk
Dragon fruit Bean sprouts, alfalfa sprouts Hazelnuts Camembert Black and green teas
Kiwifruit Butternut squash Macadamia Brie Rice, oats, quinoa, corn
Pineapple Bell peppers Peanuts Feta Rice, oats, quinoa, corn
Raspberries Carrots, turnip, white potato, parsnip Chia seeds, pumpkin seeds, sesame seeds, sunflower seeds, poppy seeds Goat milk and cheeses Hemp, almond, oat or rice milk
Honeydew and cantaloupe melon Cucumber Parmesan, grano padano
Aubergine (eggplant), courgette (zucchini)

Following a low FODMAP diet shouldn’t be too difficult if you get the right help – there are now plenty of online resources and cookbooks that feature recipes that restrict problematic foods, but only if you’ve had professional help first.

Please do let me know if you found any that were particularly helpful for you and we’ll feature them here.

Resources for a Low FODMAP diet

If you would like to follow a low FODMAP diet, ask your GP to refer you to a dietitian. Alternatively, you could go private and hire one yourself by searching the BDA-approved freelance dietitians website for one near you (UK only).

Only dietitians are trained in low FODMAP diets (and not all! So you’ll need to ask).

If you prefer an alternative medicine route, then go to BANT to search for a nutritional therapist – but they are not trained in low FODMAP diets and will instead give you alternative advice following the functional medicine framework.

American Gastroenterolgical Association – online
Diet vs. Disease – online
Gastroenterology Society of Australia – online
IBS Network – online
Monash Low Fodmap Diet – online
Regular Girl – US

Still didn’t work?

You’re not the only one! Low FODMAP diet does work for the majority of people who try it. But we’re all so different!

There could be other factors at play, such as ongoing stress or anxiety – which can play havoc with your gut.

Talk to your doctor about your options.

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