IBS and weight gain: Is there a link?

The term irritable bowel syndrome can often feel like a catch-all term for any sort of stomach pain or discomfort. Whether you have diarrhoea, constipation, cramps or queasiness, the odds are that if you go to the doctor, it'll be one of the first potential diagnoses put on the table.

This makes sense — IBS affects almost 20% of the population, but with so many people suffering from the condition, conversations around factors like symptoms, causes, and weight loss or gain can get a little complicated.

As a result, understanding what irritable bowel syndrome is, what its causes are, and what its relationship is with your diet, lifestyle and weight becomes really important.

After all, if the relationship between weight and other gastrointestinal diseases such as gastroesophageal reflux disease is well established [2], it does beg the question of how IBS interacts with your broader health, body image and BMI, and whether or not it may help or hinder your journey to a healthy weight.

What is irritable bowel syndrome?

Irritable bowel syndrome, also known as IBS, is a chronic functional gastrointestinal disorder affecting approximately 1 in 5 people at some point in their lives, making it a very common condition [1].

It tends to affect women more than men, and while its symptoms vary from person to person, it generally includes gastrointestinal symptoms such as [3]:

• Abdominal pain and/or discomfort
• Stomach bloating and wind
• Chronic diarrhoea, constipation or both
• A feeling that your bowels aren't fully emptied after you use the toilet

IBS isn't a condition that causes lasting damage, and research has found that it doesn't contribute to the development of serious bowel diseases such as bowel cancer or colitis [1].

What causes IBS?

Irritable bowel syndrome is one of those fickle diseases that has no one determinate cause.

Of the many studies that have been conducted on the condition, the results have found that IBS is triggered by a whole host of things including:

• Diets that are low in fibre, high in unhealthy fats and high in fermentable carbohydrates (such as fructose and lactose) [2]
• Emotional stress
• Psychological distress
• Changes to routine
• Infection
• Some medications [3]

Other factors that have been found to trigger IBS symptoms include neurotransmitters, gut microbiota, and intestinal motility [1]. In other words, some causes may be easier to address than others.

It's important to note that IBS usually manifests itself for the first time in your 20s, and it's uncommon to develop it for the first time after the age of 40.

If you are developing these symptoms for the first time past that age, it may be a more serious digestive illness such as inflammatory bowel disease and you should speak to your doctor [1].

Can IBS cause weight gain?

The relationship between IBS and weight gain is under-researched, with few studies having been committed to exploring the role that this condition plays in weight management.

That said, one recent study has found that there's a tenuous link at best, and IBS weight gain appears to be more dependent on the population group being studied.

This implies that eating habits, diet and trigger foods are likely more significant considerations in both IBS and excess weight than the disease itself [2].

Can IBS make weight loss more difficult?

There's no evidence to suggest that IBS can make weight loss more difficult, nor any that suggests it makes it easier either. That said, the nature of irritable bowel syndrome symptoms means that people may make diet or lifestyle changes, that in turn affect their weight.

This might take the form of a restrictive diet or identifying trigger foods — certain foods that you know cause you to have an IBS episode — and removing them from your diet [4].

Given IBS trigger foods tend to be ones that are low in fibre and high in unhealthy fats and carbohydrates [2], this can lead to a shift towards healthier eating habits and a healthier weight as a result.

IBS doesn't cause unexplained weight loss though, so if you have not changed your diet and find you suddenly lose weight unexpectedly, you should speak to your doctor.

Can IBS make your stomach look bigger?

As one of the main symptoms of irritable bowel syndrome is stomach bloating, unfortunately, IBS can make your stomach look bigger than it really is [3].

This level of gas and bloat can be caused by certain foods such as broccoli, brussel sprouts, cabbage, cauliflower, corn, leeks, onions, beans and peas, so if you are susceptible to IBS bloating, avoiding these foods may help you to decrease the look of your stomach [4].

How to manage your weight with IBS

Managing your body weight while also trying to manage IBS symptoms can be a more complex challenge than you may expect, particularly as some fruits and vegetables that are usually recommended for weight loss and general health can actually be the ones that trigger these symptoms.

As a result, working with a nutritionist within a guided, supportive programme such as Juniper's Weight Reset Programme can help to ensure you are not only hitting your healthy weight target but also supporting your digestive tract.

You can kickstart your weight loss journey with Wegovy or Mounjaro, two groundbreaking weight loss medications that mimic the GLP-1 and GIP hormone respectively to help control cravings, delay stomach emptying, and keep you feeling fuller for longer.

Plus, we have a team of expert dietitians and health coaches you can consult with, to help you work through any challenges you're experiencing during your weight management journey. This holistic approach sets you up for sustained weight loss, rather than a quick-fix solution.

Some other tips for managing your weight changes with IBS symptoms include:

Identify your trigger foods

This might be in food that increases gas and bloating such as broccoli, brussel sprouts and cabbage, or in difficult food or drinks which are either acidic, spicy, caffeinated, carbonated, alcoholic, or include mint.

Figuring out what foods trigger your specific IBS symptoms is invaluable when it comes to making a healthier you.

Avoid skipping meals

If you find your IBS symptoms triggered by big breakfasts, lunches or dinners, don't start skipping meals, instead, try and break those larger meals into 5 or 6 smaller ones.

You should not allow IBS to force you to limit your food intake — it's crucial that you continue to consume the nutrients your body needs — and these smaller meals and snacks can help you to do just that.

Adjust your fibre consumption based on your symptoms

Fibre is vital to your intestinal motility, so if you have constipation-predominant IBS, eating more high-fibre foods such as fruit, vegetables, whole grains, oats, brown rice, seeds and nuts can help.

On the other hand, if you have diarrhoea-predominant IBS, avoiding those high-fibre foods until your episode is over will help you move forward.

Avoid foods that are high in unhealthy fats and oils

These include processed meat, fatty meat, fried foods, and foods prepared with a lot of oil or fat.

Instead, eat foods rich in healthy fats and healthy oils such as lean meat, fish, and poultry without skin, and swap butter out for nut butters or soft margarine.

Stay hydrated

Drink at least 8 cups of water a day. Water not only helps to prevent constipation but also prevents dehydration which diarrhoea can make you susceptible to.

Eat more probiotics

Consume more probiotics either through supplements or in foods where they are found naturally such as in yoghurt and kefir.

Consider a low FODMAP diet

Many studies have shown that a low FODMAP diet (Fermentable oligosaccharides, disaccharides, monosaccharides and polyols) can help you manage IBS symptoms.

FODMAPS are a group of short-chain carbohydrates found in foods that are hard to absorb and, as a result, easily ferment in the gut, which in turn causes symptoms such as gas, bloating and diarrhoea [4].

Whether you gain weight or lose weight, ensuring your body has the right nutrition is vital when it comes to IBS symptom management. If in doubt, speaking to a medical professional can help to point you in the right direction.

Whether that's a doctor, chemist or nutritionist, understanding how IBS may impact your broader health can lead to you developing better eating habits for your body, and help you to create a healthier, happier you.

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