Ep.23 IBS and dietary fats – how fat affects your digestion
3 Nov, 2023

Episode Intro

Do you struggle to eat fatty meals? Maybe you feel it sets off your dash to the toilet, or you just feel really nauseous and like food sits really heavy in your stomach for hours after eating. It's not 100 percent clear what the link is between IBS and high fat meals that's what we will explore today on this episode of the Inside Knowledge, I'll run through the difference between healthy fats and fats to reduce in our diet, as well as how to improve fat digestion, and we'll cover how fats might be affecting your IBS. I'll also briefly talk about bile acid malabsorption, which is a common cause of diarrhoea predominant IBS.


Podcast transcript

Welcome to episode 23 of the Inside Knowledge with me, Anna Mapson.

We’re starting today talking about fats for IBS. So, what kind of foods you can eat more of. What kind of foods you should potentially avoid if you have got a sensitivity to fats. But I’m going to explore a bit about why you may have that. And what fat actually does to our digestion.

Why do we need to eat dietary fats?

I first thought I’d start with though, what fat does in our body. Why do we need to eat fats? And it is a really important macronutrient in our dietary profile.

So we need fats to help us make our hormones, to keep all our cells healthy. A lot of our brain is made of fats. Also we have fat soluble vitamins, which we can only absorb if we’re eating sufficient fat in the diet. That’s vitamin A, vitamin E, D, and K.

So, there’s really no doubt that we do need some fat in our diet. We need a selection of dietary fats, which can help us create these core biological processes. Like keeping our hormones going, making our cells function well. You know, these are important processes.

Enough fat but not too much

However, we are surrounded by a food environment that really promotes availability of high fat foods a lot. There’s an opportunity, if we wanted to, to eat high fat foods all the time. And as humans we haven’t really developed in order to eat such a large amount of fats.

Fatty foods are more energy dense

Fat, when you eat it, per gram has nine calories compared to carbohydrate and protein which is four calories per gram. So there’s a lot more energy in fats per gram of the food rather than say compared to proteins and carbohydrates. I’m not going to go into the energy density of foods or talk about weight gain in this particular episode.

I just want to talk about the digestion of fats and how it might be affecting your IBS.

How fat affects your digestion

So, high fat meals, we know, are associated with IBS symptoms and particularly things like diarrhoea, cramping and gas.

Although, some people find that it can also lead to a slower transit time and I’ll explain a bit about that. Why and how that is from an evolutionary perspective humans have needed to extract as much energy from foods as possible. And so we’ve got a slow digestion of fats in the small intestine in order to allow that process to happen.

Slow transit can lead to more gas

The way that affects IBS is that when your gut slows down to try and absorb more nutrients from the meal, it could mean that your gas transport or the passage of gas through your gut is slowed down.

This is probably worse in people who have IBS because you have more gas, potentially. And also more sensitivity to the gas. So that hypersensitivity, will mean that you feel more pain and more discomfort from the same amount of gas that somebody else might have. But also because it’s going slowly through your small intestine, you can feel very bloated and feel very uncomfortable.

You might also find that you get more contractions of the small intestine as your muscles are trying to move the food through the gut. So because of it slowing down to try and absorb the calories or the energy out of the food. But then the smooth muscle is pushing and cramping trying to move it along.

Now that could also increase your symptoms and feelings that your IBS is flaring up.

How are dietary fats digested?

If we look at how fat is actually digested in your gut, then we can talk about why that might not work so well if you have IBS or other digestive conditions.

Firstly, obviously, you’re chewing it in your mouth. There’s a little bit of lipase, which is the enzyme that breaks down fats released. In your stomach as the food travels down into your stomach. It’s mashed up and there’s a little bit of lipase in your stomach. But then, as your food goes into your small intestine, you will release bile from your liver. Well, your gallbladder, which then helps to emulsify the fats.

Making fats water soluble to digest

Because fats aren’t water soluble, and we need them to be water soluble to get into cells. And transport around the body better. We want to break them down to their smallest components. And bile, it emulsifies them. So, a bit like when you have washing up liquid. It makes the fat globules smaller so that we can wash them up. A little bit the same that’s happening in your digestive system.

So once you’ve got bile released into the small intestine that’s emulsified the fats which increases the surface area. Then you get some digestive enzymes which break them into smaller fatty acids. Lipase from your pancreas that breaks down the fats from your food.

Then It can be acted upon. And help to transport the fats into the cells so that we can actually start to use it.

The role of bile in fat digestion

Now, the bile that I mentioned just now, which comes from the gallbladder and helps to break down the fats. It contains something called bile acids. These are normally reabsorbed in the small intestine.

It does its work, it emulsifies the fats, helps us better absorb them. And then at the end of the small intestine, we normally reabsorb the bile acids. They can go back to the liver to be recycled.

About 97 percent of them are reabsorbed and recycled for use again. But, if some of them are not well absorbed and they’re left to get to the large intestine. Then you get diarrhoea and abdominal pain and very bad IBS symptoms. That is due to the irritation that the bile salts are creating in the large intestine because they shouldn’t be there.

Bile acid malabsorption

They should be reabsorbed into the small intestine and then sent back to the liver. If they get to the large intestine, they can cause a lot of irritation. And this happens often because of small intestine bacterial overgrowth.

SIBO and bile acid diarrhoea

So if you have got an overgrowth of bacteria in your small intestine, it can interfere with this reabsorption process. You’re getting a release of bile acids in a normal way when you’re eating your food. Then it doesn’t get reabsorbed because of SIBO, and then it can cause diarrhoea.

So this is one way that eating fats may trigger IBS like symptoms in people who haven’t got a good digestion.

Digestion of fats via lipase enzyme

The other way that people may malabsorb fats is if you’re not producing enough of the enzymes.

So lipase is the one that breaks down fats. Again, in the small intestine. If your pancreas is not producing enough of these enzymes, it may be the case that you don’t break down the fat. Then you have very fatty stools. You might notice this by yellow or orangey looking poo that’s very frothy, diarrhoea. And sometimes a floating stool as well.

Fatty meals can lead to floating stools

Now that can sometimes be because you haven’t broken down the fibres as well. But if you think about fats, they always rise to the top of the water. The same thing will happen if you’ve got a lot of undigested fats in your stool. You will see it floating in the toilet.

Just to recap, the ways that high fat meals can affect your digestion is

  1. either you don’t have enough enzymes, being produced in your pancreas, and this can be a condition which isn’t IBS called exocrine pancreatic insufficiency. Basically just means you’re not producing enough of your own digestive enzymes.
  2. It may be that you’ve got bile acid malabsorption, so you’re not reabsorbing your bile acids, and that’s irritating the colon on your large intestine as it’s reaching there.
  3. Or it may be that a high fat meal is slowing down the transit of gas through your digestion and that is leading you to feel very uncomfortable after eating high fat meals.

What are healthy dietary fats?

Now, let’s have a little think about good fats and bad fats and which ones we’re encouraged to eat more or less of.

Good fats for IBS

When we’re talking about healthy fats, it’s usually referring to monounsaturated or polyunsaturated fats. This is just relating to the size of the chain of the fatty acids and how many of the bonds between the acids are saturated.

Generally, we need to reduce our saturated fat intake. Cut down on the amount of butter, red meat with high fat content and processed foods. These are not good for us and not good for our heart, but also not particularly good for digestion either.

Monounsaturated fats are good for the heart

Monounsaturated fats are found in foods like olives, olive oil, nuts. And avocados. These fats are known to lower inflammation throughout our body. They might help with lowering blood pressure and might even reduce the likelihood of having heart disease. So this is foods that are rich in the Mediterranean diets.

If you think about, you know, nuts, seeds, olives, these are great foods for including in your diet.

Omega 3 fats

And then we have polyunsaturated fats and these are essential fatty acids. That means our body cannot make them but we need them. So in order to be healthy we need a good reliable source in our diet of omega 3 and also omega 6.

Now we get that from foods that we eat.

The best source of omega 3 is oily fish. There’s a little acronym called SMASH to help you remember which fish are the good ones for oil, and that includes sardines, mackerel, anchovies, salmon, and herring.

Some omega 3 can be obtained from plant based sources like flax seeds, walnuts, hemp, and sunflower seeds. But the omega 3 in that is not as available to our body as the one from fish.

Vegan omega 3 supplements are available

If you are a vegan, consider a vegan omega 3 supplement made from algae. That’s seaweed. Because the way we get omega 3 supplements is because the fish eat the seaweed. Then people, catch the fish, and take the oil from the fish. If you are vegan, there’s a supplement that’s made from the seaweed. It’s in a gelatine free capsule, and it will be suitable for vegans.

This omega 3 is really important for our overall health. And it helps with mood. It helps with mental health, like cognition and concentration. It’s also been tested for, skin health. So thinking about the people who have eczema and high levels of dry skin, that sort of thing.

So, if you’re not eating oily fish, I strongly suggest that you think about whether an omega 3 supplement is suitable for you.

You don’t even have to take it every day. Just including it at some point throughout your week in your diet. Because, as I said, it is an essential fatty acid. Generally, people tend to be pretty low in it. Those oily fish that I mentioned are not the ones that people like to eat very often.

Omega 6 fats are a healthy fat to consume

Now, you might hear people talk about omega 6. That we need to reduce our intake of the other polyunsaturated fat, omega 6. This is more freely available in things like nuts and seeds, meats. You can get omega 6 fairly easily from the diet.

People will talk about reducing down omega 6, especially plant oils. Things like sunflower seed oil, vegetable oils, you might see them called.

This actually isn’t true. Obviously, we need to monitor the overall levels of fat in our diet. As I mentioned at the beginning, fat has a higher energy content per gram than protein, or carbohydrate. This means it’s energy dense.

If you’re eating food with a lot of fat in it, it will have a higher amount of energy than food without fat in it. So, we don’t want to just eat lots of fats.

Omega 6 is anti-inflammatory when switched for saturated fats

There is really good evidence for having less saturated fat in your diet and more plant based fats. Including vegetable oils, omega 6 fats, because it’s anti inflammatory.

This helps to reduce down the risk of heart disease. Swapping out things like butter for plant based margarines can be very important if you have high cholesterol. If you have a history, or a family history of heart disease.

The ratio of Omega 3 to 6 is not important

You might also hear people saying that you need to keep the ratio of omega 3 to omega 6 in balance, and there’s also zero evidence for that.

There’s no evidence that says having a certain ratio of omega 3 to omega 6 is better for you. Yes, people are eating more fat now. And that is true. As I said at the top of the show, we’re living in this environment where we have got access to high fat foods and high energy density foods all the time.

It doesn’t necessarily mean the ratio is wrong. We need to manage our overall energy intake. Make sure that fat is a controlled proportion in order to not eat too much fat which has a negative impact on the rest of our body, not just digestion.

Eating nuts and seeds is healthy

Anyway, we’re veering off digestion a little bit here, but it is something I get asked about a lot and including things like Is it okay to eat a certain amount of nuts? Is it okay to cook with vegetable oil?

And the answer to that is yes, it is okay to eat nuts and it is okay to cook with vegetable oil.

How to manage sensitivity to dietary fats in IBS

Anyway, let’s finish up just talking about what you can do. So if you feel that fat is a problem for you and your diet, what kind of things can you change in order to get less symptoms?

I expect that’s why you’re listening to this episode.

Consider your overall eating pattern

Overall, I’d like you to think about your. eating pattern as a whole rather than meal by meal. When we’re thinking about gut bacteria, we’re just looking at your overall dietary pattern. And people who eat a sort of typical Western diet with high carbohydrate, high fat content, typically have gut bacteria more associated with chronic disease, chronic low level inflammation, and digestive complaints.

So overall, I want to try and modulate that by trying to change it to a high fibre diet so you’re eating more fibre, less high fat, so looking at the overall dietary pattern, not meal by meal.

But just thinking How much fat would you say you’re eating in a day? How much fibre would you say you’re eating in a day?

Eat some healthy fats

Then, we also want to try and make sure that you are including some of these healthy fats like avocados, nuts, oily fish and trying to reduce down the other fats like, processed meats, burgers, chips and fried foods, those kind of things because they tend to be higher in saturated fats. One of the other reasons that fibre is so helpful is it does help remove bile salts and help to reduce the impact of bile salt malabsorption.

Support your liver

The other thing you can do is really protect your liver and that is to help you, because they’re making the bile salts. We want to make sure that our liver is functioning as effectively as possible. So, reducing high alcohol intake. And if you’re someone who has a glass of wine every day or you drink a lot on the weekends, your liver may be working overtime. And may be struggling a little bit.

So, just simple things you can do. You don’t need to do any sort of detox or cleanse or anything. But just simple things like you’re cutting down your alcohol to within the recommended guidelines or lower and drinking lots of water.

Support fat digestion

In terms of what you can take to help aid fat digestion, there are digestive enzymes that include high levels of lipase. That’s the enzyme breaking down fats. You could try taking a digestive enzyme with high fat meals to see if it eases your symptoms the next time. Just carry them around with you in your bag or… car or whatever and then when you need them just take one with the high fat meal to see if it makes it easier to digest.

Consider bile acid malabsorption with your doctor

The other thing you may do is talk to your doctor about bile acid malabsorption. If you’re someone who has frequent watery diarrhoea that is erratic and you don’t know what’s causing it, keep going back to your doctor. Make sure that they have run the right kind of tests or considered the right kind of medication.

If you do think bile acid malabsorption is an issue for you, there is medication that you can get which helps to remove the bile salts from your digestive system so that they don’t irritate the colon. But this does have other health complications because it can reduce down your cholesterol. If you’re not someone who needs to have their cholesterol reduced, this can have negative consequences. So it does need doctor’s medical management.

Keep to a healthy balanced diet

Okay, I hope that has been useful. I don’t want people to be afraid of fats. Like I said at the beginning, we need fats in our diet but we need more of the plant based fats ideally and the oily fish and less of the saturated fats. Overall, to try and keep a healthy, balanced diet and hopefully you can enjoy eating some of these fatty foods on occasion and not worry about it as long as you are creating a good gut environment.

Now that is. Easier said than done, I know.

Work with me in the 3 month Gut Reset

And if you want to work with someone on your digestion, please get in touch. I run a three month gut reset, either on a one to one basis or in a group which is a slightly lower cost and you have group coaching sessions. People have been really like learning off each other and enjoying some of the interactions. Or there’s like a private sessions where you have one to ones with me.

These all run for three months. I find that is a good amount of time to really start to help people understand what foods work for them.

So if you’re not sure and you want to talk to me about it then please get in touch and we can talk about what you need help with. All right, I’m going to leave it there for this week. Thank you. Goodbye.




Ep.31 Supplements for SIBO – IBS Podcast

SIBO SupplementsWelcome to episode 31 of the Inside Knowledge. I am Anna Mapson. Today, talking about supplements for SIBO (Small Intestine Bacterial Overgrowth). (For background on SIBO listen to Episode 11 - What is SIBO  and Episode 12 - Treating SIBO) Confusion...

Ep.24 Are abnormal eating patterns making your IBS worse?

IBS and Disordered Eating PatternsWelcome to episode 24 of the Inside Knowledge with me Anna Mapson. Today I want to talk about something a little bit different. It's not specifically about IBS and how to treat it, but it's more a reflection of some of the ways I see...

Ep.22 Supplements for IBS – IBS Podcast

Supplements for IBSWelcome to episode 22 of the Inside Knowledge with me, Anna Mapson. Today, I'm going to talk a bit about supplements for IBS. Generally, most people I work with come to me and are on quite a few supplements already. Not everybody, but a lot of...

Ep.20 Navigating IBS Flare-Ups – IBS Podcast

Helping yourself through an IBS flare up Welcome to episode 20 of the Inside Knowledge with me, Anna Mapson. This is a podcast for people who have IBS, and I couldn't carry on without focusing on what to do in a flare up. This is going to be some helpful advice and...

Ep.18 Mastering FODMAP reintroduction – IBS Podcast

Mastering FODMAP reintroduction to your IBS dietWelcome to episode 18. This is The Inside Knowledge with me, Anna Mapson. The reintroduction phase of the low FODMAP diet is something most people, I find, don't get round to. They eliminate foods from their diet. And...

Ep.19 Should you go dairy free if you have IBS? IBS Podcast

Should you go dairy free if you have IBS?Hello! Welcome to episode 19 of The Inside Knowledge with me, Anna Mapson. I work with people who have IBS. And so all the time I'm talking about diets that are good for the gut, what you can do to avoid problems like bloating,...

Ep.16 Should you go gluten free if you have IBS?

Should you go gluten free if you have IBS?  Welcome to episode 16 of the Inside Knowledge with me, Anna Mapson. Today is all about gluten, gluten free diets and wheat. And what is the difference between all these different foods? Where should you focus your...

Ep.10 How that dodgy takeaway years ago caused post infectious IBS

What is post infectious IBS?Hello and welcome to episode 10 of the Inside Knowledge for People with IBS. I'm Anna Mapson. Today, I would like to talk to you about post infectious IBS and how some of the symptoms that you're getting can start after an incident of food...

Ep.9 IBS success stories – taking control of IBS constipation

IBS-C stories from the Gut Reset. .In today's episode, we're diving into the experience of four of my previous clients who suffered from constipation predominant IBS. You'll hear how they improve, improve their bowel regularity, changed their diet, diversity, and...

Ep.8 Improving a vegetarian diet when you have IBS

Improving your vegetarian IBS dietYou'll learn which kind of vegetarian protein foods are less likely to make you bloat, how to actually calculate how much protein you need. I'm going to talk about how to manage the low FODMAP diet as a vegetarian and what's the deal...