Ep.38 – IBS & weight loss: a battle of the diets
22 Feb, 2024

Episode Intro

Are you fed up of trying to lose weight and feeling frustrated that your healthy food is just triggering IBS symptoms? It can feel, to most of my clients, like typical weight loss advice is telling you to eat food that just makes you feel bloated, gives you stomach aches, or sends you running to the toilet all day. I work with people who've got IBS, and typically some of these also want to lose weight. So I help them resolve digestive issues alongside a diet plan. Now this episode won't be suitable for everybody, maybe you don't want to lose weight, maybe you're the opposite and you actually need to gain weight. I will be coming to that later in the year, but this episode and the next This next one is going to be about how to lose weight with IBS.

Podcast transcript


Weight loss & IBS – a battle of the diets

Welcome to episode 38. I’m Anna Mapson and this is the Inside Knowledge for people with IBS.

This week is the first week of a focus on weight and IBS. And I’ve wanted to do this in a sensitive way. I realise it’s a tricky topic for a lot of people. There are sensitivities with how we talk about weight and body shape.

The struggles with weight loss and IBS

And just to set the scene, I’m going to use terms like being overweight or obese because that is how the research describes people. But to also be very clear, I don’t think that necessarily, if you’ve got a larger body mass index or BMI, it necessarily equates to being unhealthy.

Also, not everybody who is in a larger body wants to lose weight. So I don’t also assume that people are trying to lose weight.

It’s just that a lot of people I work with come to me. And they come for their digestive issues, but they say, and I also want to lose weight.

Weight loss goals with IBS

I have got plans to run a weight gain episode, a couple of those, because I also work with a lot of people who really struggle to put on weight. But that’s going to be pretty much the opposite of what we’re talking about today.

If you’ve been trying to lose weight, but are really struggling because of your digestive discomfort every time you try to change your diet, then you are not alone.

There are some data that show the majority of the adults in the UK are classed as overweight or obese. And when we’re talking about that, like I mentioned, they’re using a BMI and people with obesity have a BMI of over 30.

IBS is common

But what is also interesting is IBS is really common. People with a sensitive digestion who are trying to lose weight, there are a lot of people.

So, there’s a study that showed that 30 percent of people with a BMI of over 30 had IBS, compared to 10 to 15 percent is like a 1 in 20, 1 in 10 incidence in the general population.

So it’s a common overlap.

IBS doesn’t cause weight gain

It doesn’t mean that your IBS is caused by being overweight, or that your weight is caused by the digestive dysfunction. So just because you are struggling to digest your food doesn’t mean that it’s causing weight gain. However, there are lots of things that it limits in your life.

If you have got serious IBS, that means it’s harder to lose weight.

  • For example, you might not be able to exercise with the intensity, the frequency as other people.
  • You might not be able to access a whole range of those healthy foods, such as high fiber whole grains, lots of fruits and vegetables. Because as we know, these are very clear FODMAP triggers. So people who have IBS are often sensitive to these types of foods.
  • It’s also the same with high protein diets that these can be very triggering for your gut.

So in this episode, I want to try and break it down a little bit and think about what is it that you can do and how to do it. I have a 20 minute limit with this. Because there is quite a lot to say I will probably do a part two breaking it down into a little bit more detail.

But we’re just going to start off.

Why is it harder to lose weight with IBS?

Thinking about what you can do and also some of the reasons why it might be harder for you.

Firstly, would losing weight improve your IBS?

Well, there isn’t really much evidence to show that people in the largest bodies have the worst IBS. So we don’t have any evidence that says losing weight will automatically help your gut issues. And in the same vein, resolving your IBS won’t necessarily cause you to lose weight. Unless you also engage in some dietary changes and exercise.

Some of the links that we can see through research and I also notice just working in my general clinical practice, that there are some associations between a symptom and lifestyle or diet.

Slow transit time can connect weight gain and IBS

So one of these is a slow transit time. If you have slow motility, that means food is moving from your stomach slowly through your small and large intestine. Which is obviously more common with people who get constipation.

There is a link between the slow passage of food through your gut and increased energy intake.

We also know that there is a link between high methanogen overgrowth. So this is bugs in your gut that create methane gas. That is very common in IBS-C, so people who get constipation. That you can be sometimes extracting slightly more calories from your diet than other people who eat the same kind of food.

High fat, high protein meals may be an issue

But at the same time we’ve got to acknowledge that higher fat, high protein meals also slow down your digestion.

So if your diet is full of a lot of fat, a lot of protein like meat, then that can slow down your digestion. You might be getting more calories from that, especially if you are low fibre.

Some people with obesity seem to be more likely to experience slow gut motility or constipation. So, that’s a bit of an overlap.

Quick digestion, IBS and weight gain

Also, you might see people who get a rapid stomach emptying. So that is your stomach empties too quickly into your small intestine. Now this can cause diarrhoea, cramps. This could be down to eating a larger meal, or it could be a reaction to the fats. Or the sugars, or certain fibres like FODMAPs.

This may be more common in people who have a larger body size.

I have got a link basically to all these studies as well.  It’s in a blog post on my website which I will post in the show notes if you want to go and research this.

Symptoms of IBS associated with obesity

There is an association of having a BMI of over 30 and an increased risk of heartburn, acid regurgitation, bloating, stool frequency. That’s like loose stools, loose watery stools, and upper abdominal pain.

So there is a potential link between your digestive problems and a larger body size. However, it’s not necessarily clear what the actual mechanism can be.

My approach to weight loss with IBS

My approach, very simply, to looking at digestion and weight loss together is that focusing on your IBS first and trying to get your digestive health good as possible is more important than the weight loss. The weight loss can come when you can eat more food.

So a very high level, simplified process would be to identify your digestive triggers. Expand out your diet so that you can eat more fruit, more vegetables, fibre. And then whole grains, things like switching from white to brown bread because this can actually help you feel fuller for longer.

So let’s go through how you can do that.

First line steps for IBS and weight loss

Before you go into any harsh restrictive or elimination diets one of the first things to do would just be to try and eat following the Eat well guidelines.

Follow the healthy eating guidelines

It is a good place to start. So for example, are you getting a good source of protein, a good source of complex carbohydrates, and lots of fruits and vegetables in your day?

Reduce gut stimulants

Are you able to cut out high amounts of caffeine? gut stimulants like alcohol, smoking, just the very basic things are some of the first places to start.

Reduce energy dense foods

So it’s kind of like before you launch into a complex low FODMAP diet, I suggest just making sure that you’re actually covering some of the basic healthy eating guidelines around eating enough fibre, eating protein, eating fruits and vegetables. Not having too many processed foods.

Just cutting out a lot of snack foods, junk foods, as whatever you want to call them. I don’t really like using all of those terms. Food is food, it’s not always good and bad.

Consider your snack foods

But if you’re eating a lot of crisps, biscuits, chocolates, chips, burgers and takeaways, that kind of thing. They are very energy dense. And will be adding additional calories to your food that you probably don’t need if you are aiming to reduce your weight.

That is step one, trying to get the easy wins, pick off the things that you know aren’t necessarily good for you.

You eat them because you love them, you love the taste and you enjoy eating them. Also very valid reasons for eating, however this episode is about how to lose weight. So, some of that is going to have to be reduced if you are eating a lot of it.

Now, obviously, I’m not giving personalized information or advice during this podcast, and if you want to work with me, you want to find out more about how to do this in a more tailored way, then let me know. But in general, this would be one of the first steps.

Secondly, trial the low FODMAP diet

Second step would then be to follow the low FODMAP diet. And follow it for a set period of two to six weeks. This is to try and get to a new good baseline so that your digestive symptoms are better. Then we’re going to go through and reintroduce the FODMAPs, which takes another kind of couple of months, like 10 weeks, roughly.

You want to try then and find out if there are particular food groups that are triggering you.

Where to get help on the low FODMAP diet

If you want information on how to do the low FODMAP diet, go back and listen to episode 17 and 18, where I explain exactly how to do that. I’ve also got multiple blog posts on my website.

What if you’ve been low FODMAP for years?

So through that process, you will find out if you have got specific triggers. Now. The other thing to mention is a lot of people I work with have been doing the low FODMAP diet for years.

It’s supposed to be followed for two to six weeks until you get a better baseline. And then you reintroduce your foods to find the triggers.

If you’ve been following it for a really long time and you don’t really know if you have got any triggers you need to Re-invigorate that low FODMAP.

Take two weeks strictly low FODMAP

So I suggest going strictly low FODMAP. Because for people who’ve followed it for years, normally you find you’re not actually following it strictly anymore, if you are honest with yourself.

And then, go through the reintroduction plan. The purpose of that is to get as broad and balanced a diet as you can within the limits of what you can cope with.

Alright, so that is broadly step two.

Lifestyle changes for IBS and weight loss

Alongside both of those steps, you also need to look at your lifestyle and whether you are trying to help yourself lose weight through burning off more energy.

Very simply, you will not lose weight unless you are burning off more calories than you are eating.

That is the very simple energy in, energy out model for weight loss.

Complexities for weight loss

There are lots of other complexities, you can look at it in a very different way. Which is that there are other things that also make weight loss harder.

  • Conditions such as polycystic ovaries.
  • certain medication, like some antidepressants or pain killing medic allergy medication.
  • socioeconomic status, so how you live, how much money you have.
  • whether you have mood disorders like depression, anxiety.

These all layer on additional complexities over and above the energy in, energy out.

Burning energy for weight loss

However, at a basic metabolic cell function level, you won’t lose weight unless you are in a calorie deficit. That is important to know.

So how can you very gradually increase the amount of energy that you are expending throughout the day. In a way that doesn’t lead you to feeling burnt out, overworked. And also that is going to make your symptoms even worse.

So we know that very high intensity exercise, like HIIT workouts or CrossFit or long marathon running, any endurance kind of exercise. This is associated with worse IBS. Because of the when you’re in such a state that your blood is pumping out to your arms, your legs, and like really get your heart is racing.

It’s good for you to do that. However, it can lead people to have worse IBS symptoms. So it either triggers off a flare or as soon as you start eating. If you don’t allow time for your blood to go back to your digestive system before you start eating.

Don’t gulp a protein shake after exercise

This is where people are like maybe drinking protein shakes quickly after the gym. This can set you up for more IBS flare ups. So, movement is good. Some of the best ways to do this is a more gentle way. So avoiding those really high intensity workouts.

Increase your NEAT

Now there is something that’s quite interesting with weight loss. We like to think about not only the exercise that you’re doing, like you might go to an exercise class or you might go for a run. But actually what is a really big portion of your energy expenditure is called non exercise activity thermogenesis, so NEAT for short.

And this is basically the way that you burn energy throughout the day. Just by normal kind of movements.

Sometimes you will find that people who are in a smaller body and find it easier to lose weight, are those people who are constantly fidgeting, jiggling around, moving, you know, they can’t sit still.

And that’s because they are always moving their body.

So the more sedentary you are, The harder it will be to lose weight.

Start exercise slowly

So where you’ve got really bad IBS symptoms, some of the things you can do is to try and build in a little bit more movement. And this is where goals like having 10, 000 steps a day are helpful.

The interesting thing about that you might have heard before is that there isn’t really any scientific basis to this 10, 000 steps. It was created by a Japanese firm who were promoting a pedometer, like that’s a step counter. And they just created the target of 10k steps a day. So there isn’t really any evidence for that.

Increase from where you are now

So, I don’t think you need to worry about hitting 10, 000 steps per day. What you do need to worry about is moving on from wherever you are now.

If you’re not somebody who does any exercise at all, maybe you drive everywhere, you don’t go for general walks, the only walk you might do is maybe around the supermarket, once or twice a week.  Just start from there.

So often on your phone, you will have a step counter. You can look at there. You don’t have to buy like one of those Fitbits or Apple Watch.

But you can check how many steps you’re doing now and then just try and increase it by a thousand. Could you get a little bit more of a walk in? Could you just walk a little bit more around the house?

So that’s the basic first steps that I would focus on is making sure you’ve got a good basic diet. Then go through the low FODMAP diet reintroduction process and alongside both of those two things increase the amount of movement that you are getting throughout the day.

Why do you even want to lose weight? 

I want to finish this episode on also challenging you on why do you actually want to lose weight? Because I think people launch into weight loss sometimes, not everybody. But thinking that life will be better when you’ve lost weight. The problem with this is losing weight doesn’t necessarily change everything else in your life.

What will change when you lose weight?

So, yes, changing your health and your body can enable you to maybe run up and down the stairs a bit freer. Maybe play with your kids without getting out of breath. You know, maybe there are things that will help you when you have lost weight.

What stays the same? 

However, some things don’t change when you’ve lost weight. Your relationships will still be the same. Your house will still be the same, your job will still be the same. So in lots of ways, life doesn’t change when you’ve lost weight.

And it might be helpful to dig a little bit more into why you want to lose weight. Because as I started at the beginning, losing weight won’t necessarily make your IBS better either.

Getting clarity on your weight loss goals

One of the things you can do to make this clear for yourself is very simply write down on two columns, what I gain and on the other side, what I will lose.

I want you to think about what will you have gained when you lose weight? And on the other side, what will you lose and what will be gone from your life when you lose weight?

What will you give up in order to lose weight?

The purpose of this is to think about what are you prepared to do in order to lose weight, and is it actually worth it?

So, for example, what would be different might be a feeling of deprivation if you can’t have a takeaway with your family each Saturday. Because that’s what you normally do. Or, at the moment, you currently reward yourself with a cake. Or you have kind of some sort of treat from your shopping every time you’ve been to the supermarket.

If you change your body size will you have to buy new clothes?

Are you gonna have to buy a new wardrobe if you get to a lower weight or a smaller body size?

Would weight loss affect your family? 

How will the weight loss activities affect you in your parenting? Like for example, are you worried about spending less time with your children if you’re going to the gym.

Are you worried about having to change all your family meals and will or people actually want to eat the food that you’re cooking this new healthy food.

Think about the change in your relationships, maybe with your partner or your friends. Will it be different if you go to a Friday night, hanging out with your mates, and they’re all drinking wine and eating crisps like normal. How will you deal with that?

Or, if you have a family routine, to have a pizza every Friday or something.

Consider what routines and habits need to change – will it be worth it?

It’s important to think about how you’re going to change, in what way can you still retain the important elements of those kinds of things whilst also thinking really openly and clearly with yourself about what it is that you are going to remove from your life or what you’re going to gain from your life.

It would be great if you could do that exercise and then just feel that clarity, realizing why it is that you want to lose weight.

Asking yourself why, why, why?

You can also go through that why questioning, like, why do you want to lose weight? Okay, I just want to be, back to a size 14 because that’s what I was when I was growing up.

Okay, why do you want to be like that? Oh, so I can wear different clothes. Okay, why do you want to wear those clothes?

Keep on questioning yourself until you get to the real part of the equation, what it is that’s important. And normally it comes down to our values, things that we hold really dear to ourselves.

So it’s about relationships, about how you see yourself, your own body image.

It’s good to question these sometimes.

Is weight loss even the right target – what else could be measured

And then the other kind of red herring that I want to throw out there is why weight is your target. So are there other things you could measure except for weight? We know that weighing yourself regularly isn’t really a good idea and the body mass index, the BMI, isn’t really a good indicator of health.

What can we measure if you are aiming to lose weight?

Well, one thing that’s really good is your fitness levels. So maybe you want to think about health outcomes that are more closely correlated to fitness levels rather than your body weight or your body size.

Fitness levels are important

So it’s helpful to think about can you run a 5k without stopping. Or it might be as simple as walking up the stairs without getting out of breath.

You need to set the targets based on where you are now. And I would suggest if you haven’t done any exercise and you want motivation then maybe look for a really good personal trainer who can help you. Because it can help to make it more specific and more targeted.

Measuring your waist-hip ratio

The other things that are potentially helpful for you to track is things like your waist hip ratio.

This is looking at the size of your waist in comparison to the size of your hips. We know that having a larger abdomen larger than your hips is associated with metabolic conditions such as diabetes.

Because you’re retaining more fat around your organs and that has a metabolic effect. So maybe, instead of thinking about weight and how many stones or kilos you are. How large your stomach is, that could be another measure. Maybe it’s to do with your clothes fit.

But weight isn’t necessarily the be all and end all of everything.

Part two of this podcast about IBS and weight loss coming up!

Anyway, I am going to come back with part two on this with a little bit more detail about some specific foods and a bit more detail about the gut microbiome as well, so listen up for that next week.

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