Why Am I So Bloated? Understanding the Causes of Bloating and What Can Help
by Joe Alvarez BSc, MSc, RD
IBS & Gut Health Dietitian
Why Am I So Bloated? Understanding the Causes of Bloating and What Can Help
Bloating is one of the most common digestive symptoms, but that doesn't make it any less frustrating. Whether your stomach feels uncomfortable after eating, your abdomen becomes visibly swollen throughout the day, or you constantly feel as though you have trapped wind, bloating can affect your confidence, social life and relationship with food.
If you regularly find yourself asking, “Why am I so bloated?”, you're certainly not alone. Bloating can have several different causes, from constipation and gas production to irritable bowel syndrome (IBS) and changes in how your gut functions.
The good news is that understanding what might be contributing to your symptoms can help you find a more targeted approach to managing them, without unnecessarily restricting your diet.
As a specialist gut health dietitian, I help people understand their digestive symptoms and find practical, evidence-based ways to improve them. In this article, I'll explain what bloating is, why it happens and what you can do to feel more comfortable.
What is bloating?
Bloating describes a feeling of fullness, pressure or tightness in your abdomen. You might feel as though your stomach is stretched, inflated or filled with air, even if you haven't eaten very much.
Some people also experience abdominal distension, which means their abdomen visibly increases in size. Others experience the sensation of bloating without any obvious change in their abdominal appearance.
Although the terms bloating and abdominal distension are often used interchangeably, they aren't quite the same thing.
Bloating refers to the sensation of abdominal fullness or pressure, whereas distension refers to a measurable or visible increase in abdominal size. You can experience either symptom independently, or both together.
Bloating may occur occasionally after a large meal, but persistent or recurrent bloating can sometimes indicate an underlying digestive issue that needs further investigation.
Why am I bloated? 6 common causes of bloating
There isn't one single explanation for bloating. The cause can vary between individuals, and several factors may contribute to symptoms at the same time.
1. Gas production in your gut
One common reason for bloating is the production of gas during digestion.
Some carbohydrates aren't fully absorbed in the small intestine. Instead, they travel into the large intestine, where gut bacteria ferment them, producing gas as a by-product.
This is a normal part of digestion. However, in some people, the resulting gas can contribute to uncomfortable bloating, wind and abdominal pain.
Foods that can contribute to gas production in susceptible individuals include:
- Beans, lentils and some other pulses.
- Onions and garlic.
- Certain fruits, including apples and pears.
- Some dairy products, particularly when lactose isn't well tolerated.
- Certain wheat-based foods.
These foods contain different types of fermentable carbohydrates, including a group known as FODMAPs. However, it's important to remember that these foods are not inherently bad for your gut. Many provide valuable fibre, vitamins and minerals, and not everyone experiences symptoms when eating them.
The aim is to understand your individual tolerance rather than automatically eliminate foods from your diet.
2. Constipation
If you're struggling to open your bowels, constipation could be contributing to your bloating.
Constipation doesn't necessarily mean you aren't going to the toilet at all. You might be constipated if you pass stools less frequently than usual, strain when opening your bowels, pass hard stools or feel that you haven't completely emptied your bowels.
When stool moves slowly through the digestive tract, it can contribute to abdominal discomfort, fullness and bloating. Changes in stool consistency and the movement of gas through the bowel may also play a role.
If constipation is contributing to your symptoms, addressing your bowel habits may be more helpful than cutting out foods.
Depending on your symptoms, this might involve reviewing your fluid intake, physical activity, toilet routine and fibre intake. Increasing fibre can help some people, but the type of fibre and the speed at which you increase it matter. Large or sudden increases in fibre, particularly bran or other poorly tolerated fibres, can sometimes make bloating worse.
3. Irritable bowel syndrome (IBS)
IBS is a common disorder of gut-brain interaction that can cause abdominal pain, bloating and changes in bowel habits, including diarrhoea, constipation or a mixture of both.
If you have IBS, you might notice that your abdomen becomes increasingly bloated throughout the day, that symptoms worsen after eating, or that bloating occurs alongside abdominal cramps and changes in your bowel movements.
IBS is not simply a case of having too much gas. Several mechanisms can contribute to symptoms, including altered gut motility, increased sensitivity to sensations within the digestive tract and changes in how the brain and gut communicate.
This means that even normal digestive processes, such as the movement of gas or stool through the bowel, can feel uncomfortable.
Stress, disrupted routines, previous gastrointestinal infections and food-related factors may also influence symptoms in some people.
If you're experiencing persistent bloating alongside abdominal pain and changes in your bowel habits, it's worth discussing your symptoms with your GP to establish whether IBS or another condition could be responsible.
4. Food intolerances and difficulty digesting certain carbohydrates
Some people experience bloating after eating particular foods because they have difficulty digesting or absorbing certain components.
For example, lactose intolerance occurs when the body doesn't produce enough lactase, the enzyme needed to digest lactose, the natural sugar found in milk and other dairy products.
Undigested lactose can reach the large intestine, where it is fermented by gut bacteria. This can cause bloating, wind, abdominal pain and diarrhoea.
Other people may be sensitive to certain fermentable carbohydrates, including fructans found in foods such as onions and wheat, or galacto-oligosaccharides found in beans and pulses.
However, experiencing bloating after eating a food doesn't automatically mean you have an intolerance to it. Portion size, the combination of foods eaten, constipation and underlying gut sensitivity can all influence how you feel after a meal.
Rather than eliminating multiple food groups, it is usually more useful to look for consistent patterns and investigate suspected intolerances appropriately.
5. Eating habits and meal size
Sometimes, the way you eat can contribute to bloating.
Eating quickly, chewing gum, drinking fizzy drinks and swallowing excess air can increase the amount of air entering your digestive tract.
Large meals may also leave you feeling particularly full and uncomfortable, especially if you already have a sensitive digestive system.
You might notice that symptoms are worse after eating out, eating late at night or going for long periods without food and then eating a large meal.
This doesn't necessarily mean you need to eat less overall. Establishing a more regular eating pattern, allowing yourself time to eat and noticing how different meal sizes affect your symptoms may be more helpful.
6. Hormonal changes and the menstrual cycle
Some people notice that bloating fluctuates throughout their menstrual cycle.Hormonal changes can influence bowel function, fluid balance and digestive symptoms, meaning you may feel more bloated at certain times of the month.
If you experience recurring bloating alongside your menstrual cycle, keeping track of symptoms for a couple of months may help you identify a pattern. However, persistent or progressively worsening bloating shouldn't automatically be attributed to hormones. If your symptoms are new, frequent or unusual for you, seek medical advice.
Why is my stomach bloated after eating?
Feeling bloated after eating is particularly common, but the timing of your symptoms can provide useful clues. For example, bloating shortly after a meal might be associated with meal size, swallowed air, stomach fullness or an increased sensitivity to normal digestive sensations.
Symptoms that develop later may be related to the fermentation of certain carbohydrates as they travel through the digestive tract, although timing alone cannot identify the cause.
Constipation, IBS and other digestive conditions can also make you more likely to experience bloating after meals. If you regularly experience bloating after eating, try to notice the wider pattern rather than focusing on one particular food.
Consider the size of your meals, how quickly you eat, your bowel habits, whether you experience abdominal pain and whether symptoms occur after a range of different foods. This information can help you and your healthcare professional identify possible contributing factors without resorting to an unnecessarily restrictive diet.
Why am I bloated all the time?
Occasional bloating is common. However, if you feel bloated most days, it is worth looking beyond individual foods.
Persistent bloating can be associated with constipation, IBS, food intolerances and other digestive conditions. In some cases, it can also be related to problems that require medical investigation.
If your bloating is ongoing, consider the following questions:
- Are you opening your bowels regularly, and do you feel that you empty them completely?
- Do you experience abdominal pain, diarrhoea or changes in stool consistency?
- Does your abdomen visibly increase in size throughout the day?
- Have your symptoms started recently, or have they changed significantly?
- Are you restricting more and more foods in an attempt to manage your symptoms?
These questions can help build a clearer picture of what might be happening.
It is also worth remembering that a degree of abdominal expansion after eating is normal. Your digestive system needs to accommodate food and fluid, and your abdomen doesn't have to look the same throughout the day. However, persistent, unexplained or worsening bloating deserves attention rather than simply being accepted as normal.
How can I reduce bloating? 7 practical tips
The most effective approach depends on what's causing your symptoms. However, several strategies may help reduce bloating for some people.
1. Establish a regular eating pattern
Try to eat regular meals rather than skipping meals and then eating a particularly large portion when you're very hungry.
Allow yourself time to eat and chew your food comfortably. If you tend to experience significant fullness after large meals, experimenting with slightly smaller, more frequent meals may help.
You should still aim to meet your nutritional needs across the day.
2. Review your fibre intake
Fibre is important for bowel health, but the amount and type you eat can influence bloating.
If you are constipated, gradually introducing more soluble fibre may help improve stool consistency and bowel regularity. Oats and psyllium husk are examples of sources that may be useful, depending on your individual symptoms.
However, increasing fibre too quickly can make gas and bloating worse. If you already eat a high-fibre diet, adding even more fibre may not be the answer.
Consider your current intake, the type of fibre you eat and whether constipation is contributing to your symptoms.
3. Stay hydrated and move regularly
Drinking enough fluid can help support normal bowel function, particularly if you are constipated.
Regular physical activity can also support bowel motility and may help ease bloating. This doesn't need to involve intense exercise: walking, cycling or other activities you enjoy can be a good starting point.
4. Be mindful of fizzy drinks and swallowed air
If you frequently experience wind and bloating, consider whether fizzy drinks, chewing gum or eating very quickly make a difference to your symptoms.
You don't necessarily need to eliminate these completely. Instead, experiment with changing one factor at a time and observe whether it makes a meaningful difference.
5. Look for patterns rather than cutting out lots of foods
It can be tempting to remove gluten, dairy, onions, garlic and a long list of other foods when bloating becomes frustrating.
However, bloating has many possible causes, and cutting out multiple foods without a clear reason can make your diet unnecessarily restrictive and potentially compromise your nutritional intake. If you suspect a particular food is contributing to your symptoms, look for a consistent relationship between eating it and experiencing symptoms. Consider the portion size and other foods eaten at the same time.
A specialist dietitian can help you investigate suspected triggers systematically.
6. Address constipation if it is present
If you have hard stools, strain when opening your bowels or regularly feel incompletely emptied, constipation may be an important part of the picture.
Reviewing fluid intake, fibre type, physical activity and toilet habits can be helpful. Some people may also benefit from medication or a suitable fibre supplement following advice from a pharmacist or healthcare professional.
If constipation is persistent, severe or accompanied by other concerning symptoms, seek medical advice.
7. Consider specialist dietary support
If bloating continues despite making general dietary and lifestyle adjustments, more targeted support may be appropriate.
For some people with IBS, a low FODMAP diet with guidance form an IBS dietitian, can help reduce symptoms by temporarily reducing certain fermentable carbohydrates. However, it isn't necessary or suitable for everyone.
When used, the low FODMAP approach should involve a structured restriction phase followed by reintroduction and personalisation, ideally with a dietitian trained in the method. The aim is to identify which foods and portions you tolerate, not to avoid as many foods as possible indefinitely.
Other people may benefit from a different approach altogether, particularly if constipation, food intolerance or another digestive issue is contributing to their symptoms.
Does bloating mean I have a food intolerance?
Not necessarily.
Although food intolerances can cause bloating, the symptom alone isn't enough to diagnose one. You may experience bloating because of constipation, the amount of food you eat, the fermentation of certain carbohydrates or increased sensitivity within your digestive system.
Commercial food intolerance tests, particularly those based on IgG antibodies, are not recommended for diagnosing food intolerances or guiding restrictive diets for IBS.
If you suspect a food intolerance, it is better to investigate the suspected food or component in a structured way, taking your symptoms and nutritional needs into account.
When should I seek medical advice about bloating?
Although bloating is common, it is important not to assume that persistent symptoms are always caused by diet or IBS.
Arrange a GP appointment if you experience bloating regularly, if it does not go away, or if you have tried dietary changes without improvement. You should also seek medical advice if bloating occurs alongside unintentional weight loss, blood in your stools or a persistent change in your bowel habits.
New, persistent or progressively worsening abdominal bloating, particularly when accompanied by pelvic pain, feeling full quickly or needing to urinate more frequently, should also be assessed promptly.
Seek urgent medical advice if bloating occurs with significant abdominal pain, vomiting, fever or a new abdominal lump. If you have severe, sudden abdominal pain or a swollen abdomen and cannot pass stool or gas, seek emergency assessment.
A GP can assess your symptoms and decide whether investigations are needed to check for conditions such as coeliac disease or other gastrointestinal disorders.
The bottom line: understanding your bloating is the first step
Bloating can have several different causes, and the right approach depends on understanding what's contributing to your symptoms.
For some people, simple changes to eating habits or addressing constipation may be enough. Others may need a more individualised approach to IBS, food intolerances or other digestive conditions.
The important thing is not to assume that every episode of bloating is caused by a particular food, or that the solution is to keep cutting more foods out of your diet.
If bloating is affecting your daily life, you deserve support that looks at the bigger picture, including your symptoms, bowel habits, diet and relationship with food.
Need help understanding your digestive symptoms?
As a specialist gut health dietitian, I offer personalised online consultations to help you understand your symptoms, explore potential triggers and develop a practical, evidence-based plan. Whether you're struggling with bloating, IBS, constipation or uncertainty about which foods to eat, we can work together to find an approach that supports both your gut health and your quality of life.
Book an appointment at https://theguthealthdoctor.com/clinic/joe-alvarez
This article is intended for general information and does not replace individual medical advice or assessment.
What is Bile Acid Malabsorption?
By Joe Alvarez MSc BSc RD
Background
Bile acid Malabsorption (BAM) is a condition which causes gut symptoms similar to those seen in diarrhoea dominant irritable bowel syndrome (IBS-D). It can vary from mild to severe and can often significantly affect quality of life.
Bile acids are made from cholesterol in the liver, they are then stored in the gall bladder and secreted into the intestines when we eat, where they play a crucial role in the digestion of fats and fat-soluble vitamins by binding fat so it can be absorbed. Usually, 95% of bile acids are reabsorbed, are recycled back to the liver. When absorption is faulty or when bile acid production is increased, high volumes of bile reach the bowel. This causes fluid to move into the colon, which causes symptoms such as; watery, erratic diarrhoea, foul smelling wind, abdominal pain, recurrent episodes of faecal incontinence, nocturnal defaecation (needing to poo at night) and oily stools. This is known as bile acid malabsorption 1,3. It is also called bile acid diarrhoea (BAD) and bile salt malabsorption, and the terms are often used interchangeably4.
The prevalence of BAM is estimated at 1% in the UK 5,6. However studies suggest that of those with IBS-D around a third actually have a diagnosis of BAM. It is widely recognised that BAM is an under-diagnosed condition and is often mis-diagnosed as IBS-D 6,7.
Diagnosis
There are three types of BAM. Type 1 is secondary to Crohn’s disease, ileal resection or radiation damage, type 2 is known as idiopathic BAM, which is the most common presentation. Type 3 is BAM caused by any other condition, this could be pancreatic insufficiency, coeliac disease, post-cholecystectomy and/or bacterial overgrowth.
The main diagnostic tool for BAM is called a SeHCat Scan. After an overnight fast, patient takes a capsule containing radioactive SeHCAT (a synthetic bile acid). Followed by 2 full body camera scans. Diagnosis is classified into mild, moderate or severe and this is dependent on the level of reabsorption of BAs, <5% is considered severe, <10% moderate, <20% mild 2. In cases where access to this scan is limited, patient can be trialled on bile acid sequestrants, and on successful improving symptoms, a diagnosis can be confirmed.
Misdiagnosis of IBS
Many studies suggest that BAM is often not considered as a possible diagnosis. A study in 2009 confirmed that idiopathic BAM is misdiagnosed as diarrhoea predominant irritable bowel syndrome (IBS-D) in 32% of all sufferers6.
Treatment
Medications knows as bile acid sequestrants are considered as the main treatment for BAM. They act by binding bile acids in the intestine, which stops them from being reabsorbed2,3. Cholestyramine, colestipol and colesvelam are the three BA sequestrants available to prescribe in the UK13. Glucagon-like peptide-1 (GLP-1) has been proposed as a potential treatment for some patients with BAM. However, this research is in its infancy and we need to await further trials and studies in order to begin using this as a treatment for patients with BAM16.
What about dietary changes?
In 2017 a study was carried out with data from patients treated at the Royal Marsden hospital in London, who had had a SeHCAT Scan that showed <20% absorption of bile acids. Patients completed a symptom evaluation prior to seeing a dietitian who advised on a low-fat diet (20% of total daily energy from all types of dietary fat). They attended a review at 4-12 weeks after their initial appointment where they provided a food diary and rated their symptoms again. The results showed that out of 114 patients there were statistically significant improvements in abdominal pain and nocturnal defecations and there was a trend of improvements in most other GI symptoms, except abdominal bloating, heartburn and tenesmus17. However, all the patient in the study had been previously treated for cancer and had BAM because of this. In addition, 44% of patients were taking a bile acid sequestrants too. Therefore, we cannot generalise these results to those with other types of BAM (Jackson et al. 2017). Watson et al showed similar results in a similar study of a smaller patient group (n=40) in 2015, also carried out in the same patient group at the Royal Marsden18.
Diet Adequacy
Treatment with bile acid sequestrant can lead to deficiencies in fat soluble vitamins4,19. Therefore, these should be monitored regularly whilst on treatment. A recent evaluation of data from patients who had undergone anti-cancer or haematology treatment found that in those with BAM 76% also had vitamin D deficiency and 50% has Vitamin B12 deficiency. Although, the latter is most likely worsened due to previous gastrectomy, exocrine pancreatic insufficiency, previous resections of ileum or impaired ileal function by previous pelvic radiotherapy20.
People with BA< may also be at risk of malnutrition if they are having severe diarrhoea. This may also affect appetite and intake. Therefore, weight and dietary intake should be monitored and advice given accordingly.
Summary
Bile acid malabsorption is a largely undiagnosed condition in which patients are often mis-diagnosed and treated with IBS-D. Dietitians have a key role to play in recognising patients who may need further investigations to check for BAM. They also have a key role in helping patients to manage the condition, potentially with a low fat diet, ensuring diets are nutritionally adequate and if necessary, that supplementation is provided.
References
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15. Camilleri M. Advances in understanding of bile acid diarrhea. Expert Rev Gastroenterol Hepatol. 2014;8(1):49-61. doi:10.1586/17474124.2014.851599
16. Valencia-Rodríguez A, Aquino-Matus J, Vera-Barajas A, Qi X, Méndez-Sánchez N. New therapeutic options for bile acid malabsorption diarrhea. Ann Transl Med. 2019;7(22):695. doi:10.21037/atm.2019.09.112
17. Jackson A, Lalji A, Kabir M, et al. The efficacy of a low-fat diet to manage the symptoms of bile acid malabsorption - outcomes in patients previously treated for cancer. Clin Med (Lond). 2017;17(5):412-418. doi:10.7861/clinmedicine.17-5-412
18. Watson L, Lalji A, Bodla S, Muls A, Andreyev HJ, Shaw C. Management of bile acid malabsorption using low-fat dietary interventions: a useful strategy applicable to some patients with diarrhoea-predominant irritable bowel syndrome?. Clin Med (Lond). 2015;15(6):536-540. doi:10.7861/clinmedicine.15-6-536
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