Losing Weight and IBS

Losing weight is hard. But, dealing with losing weight and IBS is even harder.

You may find that ‘healthier’ meals make IBS symptoms worse and that high intensity exercise, designed to burn those calories, triggers symptoms.

But, did you know that there may be additional changes in the body which make it harder to lose weight for those that have IBS?

In this article I am going to cover all these elements and provide practical insight on what can be done.

What is Obesity?

Although you may hear terms like ‘overweight’ or ‘obese’ being used a lot, it is important to understand that these are specific scientific terms.

The World Health Organisation’s definition for overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health (8).

If you are obese then your BMI is over 30kg/m² and if you are overweight then your BMI is over 25kg/m_².

Does IBS Cause Weight Gain?

Normally, with IBS, the main concern is that people lose weight due to the multiple diet restrictions. This then leads to a reduction in calorie intake and thus weight loss.

However, the research in this area is a little grey.

There has been studies to show a link between IBS and a lower BMI (2). But also research to show that people with IBS have a normal or overweight BMI (3).

Regardless of lack of clarity in the research, many of my clients who are trying to lose weight with IBS report having difficulties.

When they try to eat ‘healthier’ foods such as salads their bloating increases making them feel pretty rubbish. 

They would also love to exercise regularly but find they have no energy or that movement triggers their symptoms.

So it is difficult to lose weight with IBS, there is no doubt about that.

What Is The Link Between IBS and Weight Gain?

As I mentioned, we do not know the exact link between IBS and weight. This is likely due to the complexity of weight in itself.

However, you may be interested to know that there are some differences in appetite regulating hormones in people who have IBS.

5 of the hormones are abnormal in people with IBS: ghrelin, cholecystokinin, peptide YY, enteroglucagon (oxyntomodulin) and serotonin (1).

The 5 Hormones That May Lead To Weight Gain In IBS;

Ghrelin (4)

• Accelerates gastric and intestinal motility
• Increases appetite and feeding
• Regulates the release of pituitary growth hormone
• Increased density of these cells in IBS-D
• Reduced density of cells in IBS-C

Cholecystokinin (5)

• Stimulates gallbladder contractions
• Stimulates intestinal motility
• Stimulates pancreatic exocrine secretion
• Inhibits gastric motility and food consumption 
• Reduced cells numbers in IBS

Peptide YY (6)

• This is released in proportional to the calorie content of a meal. The more released, the person reduces their intake.
• Reduced cells numbers in IBS

Enteroglucagon 

• Reduces gut motility and secretion
• Proportional to the calories consumed 
• Reduced cells numbers in IBS

Serotonin (1)

• Increased in IBS-D
• Decreased in IBS-C
• Mildly reduces appetite (7)
• Reduced cells numbers in IBS

In both IBS-C and D – the 4 types of cells which produce hormones that lead to a reduced appetite are reduced in numbers (1).

As people who have IBS-D have more grehlin producing cells it may well be that this subtype of IBS gain weight more easily.

Although these are some interesting findings, much more research needs to be done. Hormones alone are only 1 tiny factor in what can cause you to gain or lose weight.

Probiotics and Obesity

You may be wondering if a probiotic will help you lose weight.

We know from research that if you are overweight or obese you are more likely to have a lower diversity of gut microbiota. This also appears to be linked with inflammation (9).

In a Danish study comparing obese and non-obese individuals, a reduction in microbiota diversity was seen. Those with the least diversity were more likely to be obese, have insulin resistance and dyslipidemia. They were also more likely to gain more weight over time (10).

Sadly we do not yet have any research which gives a defined link between obesity and gut microbiota. We can’t even say if obesity causes the changes in gut microbiota or the other way around (11).

Until further research is done it is impossible to then design a targeted probiotic to help with weight loss. And, it is unlikely to show significant results on its own given the complexity of obesity.

Obesity in humans is caused by a multitude of factors such as diet, lifestyle, mental health, medications and even genetics.

Losing Weight With IBS – How?

Although there is so much unknown about the link between obesity and IBS there is a clear way you can lose weight with IBS.

It needs to be a structured approach so that you do not feel lost. I have outlined this approach below.

1. Low FODMAP Diet

Let me be clear, this diet is not designed for weight loss. What this diet is designed for though is to pin-point your triggers foods. 

On starting this process you will immediately be changing your diet to foods that should no-longer trigger your IBS. This will open up a larger range of reduced calorie and higher fibre options that you may previously have struggled to find.

After the initial 4-6 week period you will then work through the reintroduction process to pin-point your exact IBS triggers. Again, improving the variety of foods which is useful when trying to lose weight.

You can read more about the low FODMAP diet here.

2. Calorie Deficit

Regardless of the various different weight loss methods you may see across the internet and social media, they all boil down to the same thing – you need to be eating less calories than what you are burning.

There are various methods such as fasting, calorie counting, low carbohydrate and portion control.

Whilst there is no one-size fits all approach, it is probably not a good idea to go down the low carbohydrate route as many carbohydrates are good prebiotic foods for your gut.

Equally fasting is not ideal as irregular meals can worsen IBS symptoms.

3. Lifestyle Changes

We know that sleep and stress can impact our dietary choices and our gut health.

Making small simple changes such can help to target both areas. Some good example of this would be;

• 8 hours of sleep a night
• 30 minutes of exercise a day
• Daily mindfulness exercises such as meditation 

It also goes without saying that exercise will help tip that calorie balance.

Take Home Message

The exact link between weight and IBS is unknown and more research is required.

We know that there are some practical barriers to losing weight with IBS and so careful, step by step planning is required.

To be successful with losing weight and IBS you need a step by step approach which includes the low FODMAP diet, calorie deficit and a lifestyle change

Last updated on July 9th, 2023 at 04:46 pm