Have you wondered why slimming clubs and traditional diets don’t work if you have IBS? Or perhaps they work for a bit, but not for the long term?

Perhaps you’ve tried slimming clubs yourself and been back again and again.

If you’ve got a sensitive digestion, or irritable bowel syndrome you’ll likely have a lot of symptoms that don’t agree with typical dieting approaches.

This is a long article, but here are some of my thoughts on why traditional diets don’t work if you have IBS.

Why IBS makes dieting harder

Restrictive dieting is tough

As soon as you’re told you can’t have something, you want it.

Psychologically we want those foods, we think about them even more when we’re told they are forbidden.

When people go sugar free you know they can only think about sugar. Or if they say I’m giving up alcohol, you really keep thinking about how you’re NOT having a glass of wine this Friday.

You might start dreaming of chocolate cakes and what you’re telling yourself you CAN’T have.

So it’s often a lot healthier in terms of mindset to allow ourselves to eat the food that we enjoy in moderation, as part of a balanced diet.

Related Post – Struggling to lose weight on a vegan diet

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Do mega low calorie diets work if you’ve got IBS?

You might sometimes see headlines around 800 calorie diet, or people online promoting diet books and plans with an 800 cal daily target. Sometimes a diet like this will be used in scientific research interventions. However, these are not recommended as a first line treatment, nor are they meant to be followed by the public.  

Eating an 800 calorie diet, over three weeks is going to be very, very tough for most people. The mental health implications of this kind of restriction are huge, causing a difficult relationship with food.

Eating such a low calorie diet should only ever be a targeted intervention done under the care of professionals.

Clinical studies understand how to reduce energy intake whilst also maintaining sufficient fibre, sufficient protein and all the different nutrients that we need. It’s unlikely you would be able to maintain all these targets on such a low energy diet. 

If you have IBS then long period of fasting can be difficult to manage. Depending on the type of IBS symptoms that you have you may find fasting or an empty stomach causes

  • cramps
  • reflux / heartburn
  • pains

Some meal spacing of around 3-4 hours, or an overnight break from eating can be helpful if you need to support your migrating motor complex, but long fasts often don’t work for IBS.

Very low fat diets don’t work

When you go on a diet eating typical low fat dieting foods you might feel very tired.

Now of course we need to go into a calorie deficit when we’re trying to lose weight. And fat has more calories than carbs or protein, so it seems like an easy win.

You won’t lose weight unless you are burning more calories than you’re taking in.

However, if you’re not eating any fat or you’re not eating enough protein, you’re not having enough fibre, for example, you will start to feel hungry.

Coping with your busy life and managing your day to day responsibilities for family, work and exercise is extremely difficult if you’re hungry.

Maybe you’ll start snapping at the kids, or struggle to concentrate on that report you need to write.

When we’re eating low fat foods, low calorie foods, you might not be feeling full or satisfied with the meals that you’re eating.

What I teach people is how to have a balanced healthy diet. A diet that really hits all of those nutritional kind of goals that we need, as well as trying to lose weight, and it is a long term solution.

And it’s not something that can be done overnight, if we want to change our habits for the good.

Effects of yoyo dieting

When you go on crash diets and then you bounce back to eating quite a lot of food it can be very hard for your body to respond and adapt to processing your energy.

Losing weight quickly may also interfere with our hunger signals, particularly a hormone called leptin.

Leptin tells us when we’ve had enough to eat. Our fat cells send out leptin to the brain to signal we’ve got enough energy, but this communication can become confused when you’re obese (a bit like insulin resistence in diabetes)

Teaching ourselves the healthiest way to eat over the longer term is a much more positive way to focus on weight loss. Progress may be slower, but it will be more sustained.


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Diet products may irritate your gut

If you’ve been part of the slimming club in the past or been thinking you need to cut down on calories you may have opted for low fat foods. These products are normally labelled low calorie or zero calorie.

And, of course, sometimes it will reduce the amount of calories in the food. But it’s not always healthier.

Firstly, the amount of ingredient in low fat products is normally much longer normally than the whole fat version. Because the food has been manufactured to be low fat, producers need to add in thickeners or extra salt or extra sweeteners, to try and make the food palatable.

Sometimes these are not as healthy for us as we think they are. Just because a foods is labelled low fat or sugar free doesn’t mean necessarily that it’s healthy.

But the other added complications with this is that sometimes the additions, e.g a thickener or like a sweetener might actually be triggering IBS symptoms.

This can be why diets don’t work if you have IBS.

So perhaps you find you switch over to the diet foods, and then suddenly your IBS is getting worse, you’re getting bloated.

And that makes you feel like you’re not losing weight because your tummy feels big.

Or you’re getting a lot of constipation, diarrhoea or excess gas. Those kind of typical symptoms in irritable bowel syndrome can be triggered in people who are sensitive to these artificial sweeteners or thickeners.

Particularly look out for higher FODMAP ingredients such as Sorbitol, Maltitol, Xylitol, Mannitol as these can be IBS triggers. 

Do artificial sweeteners help weight loss?

If we cut out sugar and rely on diet products sometimes we can compensate for high levels of sweetness in foods because we feel like, ‘oh well we’re being good’ and we’re having the diet drink so actually, it’s okay to have the cake.

So maybe you actually add snacks or ‘treats’ into your day, because you are restricting calories by choosing diet versions of foods.

Rewarding our brain

When we eat food containing fat chemical messages tell the brain that we’re full and we’re receiving fat and that we should stop eating.

When we eat food that doesn’t reward us in the same way, because there is no fat in your diet, we won’t get those messages back to the brain telling us we’ve had enough to eat.

And this may actually increase your appetite because your chemical satiety signals like that tell us before we’ve had enough to eat, or not being activated in the same way.

If we’re only partially satisfied with food, then we are more likely to eat more later on.

Try to eat food in its most natural form as whole or close to the origin as possible. Include fruits fresh fruits, vegetables, meat, and reduce  ultra processed food.

A ‘healthy diet’ may trigger your IBS

Eating more vegetables, whole grains, beans and pulses and fruits would be part of my typical weight loss recommendations, but actually these foods may increase IBS symptoms.

Read my blog about this here: Why IBS makes weight loss hard

It’s a very individual reaction to these kinds of foods and something that you will need to work out for yourself. But, as an IBS nutritionist I can help you do that and help you work out what types of foods are triggering your symptoms.

If you’re ready to start a weight loss journey, and you have IBS contact me.

There are lots of ways to tackle and IBS diet, we can run stool tests, and work on elimination diets to find what works for you. Send me a message to get started.

Hi I'm Anna Mapson, registered Nutritional Therapist.

I help people with IBS and SIBO get control of unpredictable gut symptoms to find long term relief from painful and embarrassing IBS without restrictive dieting.

I can help you to:

  • understand your digestion better, so you recognise your triggers
  • eat a well balanced diet, with tasty meals that are simple to prepare
  • develop better digestion and more energy

Find more about my 3 month 1:1 Gut Reset programme

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