IBS and weight loss: how to diet without triggering symptoms

15 February 2022

Losing weight while suffering from IBS can be a challenge. Many healthy foods usually encouraged for weight loss can trigger IBS symptoms.

But there are also lots of diet tactics for managing IBS that are also appropriate for weight loss. It doesn’t need to be complicated, the main message is to focus positively on what you can eat, not what you can’t.

In this article I will explain why weight loss can be tricky with IBS, which weight loss tactics will work without triggering IBS symptoms, and provide some recipe inspiration to help you on your IBS weight loss journey.

Let’s dive in!

Why is weight loss even harder with IBS?


We know that the most effective diet for long term sustainable weight loss is the Mediterranean Diet. This includes plenty of foods low in energy density and high fibre, such as lentils, beans, fruit and vegetables, nuts and wholegrains.

As an IBS sufferer you night be wincing at this list! Many of these foods are high in FODMAPs, or fermentable carbohydrates. These ferment in our large intestine, which produces gas and draws water into our guts, and can trigger symptoms of pain, wind, bloating, diarrhoea, or constipation.

Artificial sweeteners

There are countless ‘diet foods’ on the market. Think zero calorie fizzy drinks, sugar-free gum and sweets, ‘diabetic’ chocolate, protein powders and supplement drinks. The artificial sweeteners used in these products are often bulk sweeteners that can trigger IBS symptoms. Check ingredients labels for polyol sweeteners:

  • Erythritol
  • Sorbitol
  • Mannitol
  • Maltitol
  • Xylitol



IBS symptoms can be debilitating, and lead to reduced exercise. When your stomach is bloated, skin-tight lycra is the last thing you want to wear. In practical terms there are not always enough toilets on a running route for emergency stops!

Key gut friendly weight loss tactics

Gentle fibre

As an IBS sufferer, it is important to work with a dietitian through the low FODMAP process to identify the types of FODMAPs you can tolerate, and in what quantity. Remember the elimination phase should be short until you experience symptoms relief, then the challenge phase will reveal which foods you can safely reintroduce.

The good news is that there are many foods that are naturally low FODMAP, and will help you eat that high fibre, mediterranean diet that is so effective for weight loss. The meal plan below incorporates these foods, but as a general rule daily oats and linseeds will help boost gentle fibre intake.

Think linseeds in porridge, soups and yoghurts or smoothies. Oats in porridge, overnight oats, or oatcakes. These are long term habits that will help not only aid weight loss, but also keep the weight off long term.

Low sugar without artificial sweeteners

The diet industry will have us believe that we can reduce calories by cutting out sugar and replacing it with artificial sweeteners. Not only can artificial sweeteners negatively affect our gut microbiome, but they are around 5 times as sweet as normal sugar, so can lead to intensified sugar cravings.

Focus instead on dialling down your sugar cravings by weaning yourself off sweet tasting foods. Cutting out table sugar, milk chocolate and sweets, and replacing it with low FODMAP fruit, dark chocolate, and savoury snacks like nuts will help with calorie control.

Caffeine up to your level of tolerance

Green and white tea intake has been linked to improved weight loss. The reason is likely due to caffeine intake increasing how much energy we burn. However caffeine is a direct stimulant to the colon, high levels are addictive and can cause anxiety, in turn causing havoc with IBS.

Caffeine tolerance levels will not be the same for everyone. If you have IBS-C (constipation-predominant IBS), you may benefit from one caffeinated drink in the mornings to stimulate a motion. For those with IBS-D weaning off caffeine until symptoms are well controlled is advisable.


Thankfully meat and fish do not aggravate IBS. Protein is important for weight loss as it helps us feel full, and is harder for the body to extract calories from than fat or carbs. Including lean protein at mealtimes as well as snacks can help keep cravings at bay – think oatcakes with nut butter and berries, or soya yoghurt with seeds and half a banana.

If lactose is a trigger to your IBS the next best alternative in terms of maintaining protein intake is lactose-free dairy or soya dairy alternatives. Oat and nut milks are very low in protein content,

Vegan low FODMAP sources of protein include:

  • Tofu
  • Tempeh
  • Quorn (check ingredients for onion and garlic)
  • Pea protein
  • Nuts, nut butters and seeds (no cashews or pistachios, up to 2-3tbsp portions)

Healthy fats

Fat keeps us full so it is also key to sustainable weight loss. Unsaturated (plant) fats are less likely to cause weight gain than saturated fats. Sources of these healthy fats include:

  • olive oil,
  • Rapeseed oil
  • nuts and seeds
  • Avocado 

Ditch the booze, stay hydrated

Alcohol provides empty calories so can hamper weight loss attempts. Excess alcohol of over 14 units a week, and more than 1-2 drinks a day can trigger IBS symptoms. Alcohol directly stimulates the colon, and can also negatively affect our gut microbiome.

Stick to no more than one drink a day that is not carbonated e.g. red wine. Otherwise stay hydrated with water, peppermint tea and decaffeinated tea and coffee.


Gentle exercise is key to controlling IBS, as well as aiding weight loss. Yoga three times a week has been proven to be just as effective at reducing IBS symptoms as the low FODMAP diet. Pick a gentle exercise you can work into your daily routine:

  • Yoga or pilates
  • Walking
  • Dancing
  • Gardening

Low FODMAP weight loss meal plan

We’ve compiled this 5 day low calorie IBS friendly meal plan to enable steady sustainable weight loss, whilst sticking to a low FODMAP diet.

Breakfast ideas for low calorie low FODMAP diet:

Start the day right with a healthy helping of fibre in the form of one of our smoothies or overnight oats.

Lunch ideas for low calorie low FODMAP diet:

Monday: Smoky Paprika Chicken salad

Tuesday: Vegan Raspberry and Mint Summer Salad

Wednesday: Vegan Mexican Fajita Tacos

Thursday: Avocado and Salmon Salad

Friday: Chilli Beef Pizza

Evening meal ideas for low calorie low FODMAP diet:

Monday: Tacos and chilli

Tuesday: Smoky Fish and Grilled Pepper Arrabiata Pasta

Wednesday: Vegan Spinach & Chickpea Tropical Curry

Thursday: Hunters Chicken

Friday: Fakeaway Takeaway Spicy Red Thai Laksa

Final Thoughts

IBS does not need to get in the way of healthy, sustainable weight loss. In fact avoiding junk food, choosing healthy fats, eating regular meals based on protein and gentle fibre, and moderating caffeine and alcohol intake are all key to both controlling IBS symptoms, as well as weight loss.

Good luck with your IBS weight loss journey, and contact UK registered dietitian Helen at The Bespoke Nutrition Coach if you would like 1:1 support with this.

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