The causes of a bloated stomach are still not fully understood and there are a lot of potential triggers. This makes it tough to know how to tackle it, so you should make an appointment with your GP if the bloating is persistent and does not go away.

However, if your bloating comes and goes and is not causing you too much discomfort, then we’re on hand to help guide you through some of the most common causes of bloating and give you some information on how to reduce bloating.

What causes a bloated stomach?

A bloated stomach is often described as a full and often painful sensation in the stomach.¹ The most common reason for a bloated stomach to occur is due to the presence of trapped gas in the gastrointestinal tract, resulting in discomfort and is sometimes accompanied by a physical expansion of the stomach area, known as abdominal distension.²

It can be hard to know why you are gassy, but typically the buildup of gas in the stomach is caused by either how you’re eating, or what you’re eating.

Bloated stomach after eating

You might find that you often have stomach cramps after eating. This is because gas build-up in the gastrointestinal tract can be a by-product of digestion.

FODMAP foods and bloating

There have been several studies that indicate FODMAP foods may cause bloating. FODMAPs (fermentable oligo-, di-, mono-saccharides and polyols) are short-chain carbohydrates that are not digested in the stomach and are then fermented by gut bacteria in the colon.^3,4 Gas is a byproduct of the fermentation process, causing bloating in some people.

Foods that may cause some bloating:

beans – rich in protein, carbohydrates but most importantly, fibre.⁵ If you want to try to reduce bloating from beans, check your portion size. The NHS suggest that heaped tablespoons are the correct portion for beans, but you may find that you need to build up to this amount slowly
lentils – like beans, lentils are also legumes high in protein, fibre and carbohydrates. Lentils also contain FODMAPs, you can reduce the FODMAPs in lentils by soaking them overnight before you eat them⁶
cruciferous vegetables, such as broccoli and cabbage – cruciferous vegetables are known for being highly nutritious, as they contain fibre, vitamins and minerals.⁷ Steaming or boiling these vegetables may make them easier to digest
garlic and onions – are a staple in most kitchens, and even though they are not typically consumed in great quantities, they are a large source of fructans, which are a type of FODMAPs. These are soluble fibres that can cause bloating.⁸ Cooking your onions is one way to reduce the amount of FODMAPs they contain, or if advised by a specialist FODMAP dietitian, some people may be recommended to avoid them entirely

Above are just some of the foods that may cause you to experience bloating. If you’re thinking about reducing or removing some of these foods from your diet, then you should always do so with the help and support of a specialist dietitian or nutritionist. FODMAP and high-fibre foods are extremely good for you, and often you won’t need to exclude all of them. Working with a specialist will be able to ensure you are doing what’s best for your circumstances.

Hormones and bloating

Food is not the only thing that can cause bloating. Hormones can often cause a bloated stomach, or at least the feeling of one. This is particularly true for people who have periods.

The two main hormones associated with periods – oestrogen and progesterone – have been found to cause the body to retain more salt and water.⁹ A 2022 study also found that progesterone slows down gastrointestinal motility, meaning that food sits in the gut for longer, causing a bloated feeling.¹⁰

Getting enough sleep, doing gentle exercise, drinking plenty of water, eating healthy foods and reducing your intake of caffeine and alcohol can all help with bloating whilst on your period.^11,12

Underlying medical conditions

Bloating can sometimes be a symptom of several chronic diseases, including:

irritable bowel syndrome (IBS) – bloating is highly prevalent among people who have IBS.¹³There's no cure for IBS but the NHS suggests that diet and lifestyle changes can often help control symptoms¹⁴
coeliac disease – this is when your immune system attacks your own tissues when you eat gluten and can interfere with the absorption of different nutrients¹⁵
colitis and Crohn’s disease – these are conditions that cause inflammation anywhere in the gastrointestinal tract^16,17

The final say

Bloating can be uncomfortable, and hard to figure out what has caused it. From your diet and your hormones to underlying health conditions there are many causes of bloating.

It's really important to see your GP if you’re experiencing bloating constantly and it does not go away. They will be able to offer you specific, tailored advice.

If you’re looking to understand bloating in more detail, check out how to reduce bloating.

Sources

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2. F. Fernández-Bañares, M. Rosinach, et al. Sugar malabsorption in functional abdominal bloating: a pilot study on the long-term effect of dietary treatment. Clin Nutr. 2006. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0261561405002219.

3. J.R. Biesiekierski, E.D. Newnham, P.M. Irving, et al. Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trial. Am J Gastroenterol. 2011. Available at: https://journals.lww.com/ajg/abstract/2011/03000/gluten_causes_gastrointestinal_symptoms_in.21.aspx

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5. Brick Mark A., Kleintop Adrienne, Echeverria Dimas, Kammlade Sara, Brick Leslie A., Osorno Juan M., McClean Phillip, Thompson Henry J. Dry Bean: A Protein-Rich Superfood With Carbohydrate Characteristics That Can Close the Dietary Fiber Gap. Frontiers in Plant Science. 2022. Available at: https://www.frontiersin.org/articles/10.3389/fpls.2022.914412/full

6. Njoumi S, Josephe Amiot M, Rochette I, Bellagha S, Mouquet-Rivier C. Soaking and cooking modify the alpha-galacto-oligosaccharide and dietary fibre content in five Mediterranean legumes. Int J Food Sci Nutr. 2019. Available at: https://pubmed.ncbi.nlm.nih.gov/30614326/

7. Klaus Peter Latté, Klaus-Erich Appel, Alfonso Lampen. Health benefits and possible risks of broccoli – An overview. Food and Chemical Toxicology. 2011. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0278691511004364

8. Bruno Pedro Chumpitazi, Ann Rhodes McMeans, Adetola Vaughan, Amna Ali, Shannon Orlando, Ali Elsaadi, Robert Jay Shulman. Fructans Exacerbate Symptoms in a Subset of Children With Irritable Bowel Syndrome. Clinical Gastroenterology and Hepatology. 2018. Available at: https://www.sciencedirect.com/science/article/abs/pii/S1542356517311850

9. Warren Thomas, Brian J. Harvey. Estrogen-induced signalling and the renal contribution to salt and water homeostasis. Steroids. 2023. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0039128X23001277

10. A. Coquoz, D. Regli & P. Stute. Impact of progesterone on the gastrointestinal tract: a comprehensive literature review, Climacteric. 2022. Available at: https://www.tandfonline.com/doi/abs/10.1080/13697137.2022.2033203

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12. NHS Choices. PMS (premenstrual syndrome) [Internet]. 2024 [cited 2024 Feb 2]. Available from: https://www.nhs.uk/conditions/pre-menstrual-syndrome/

13. NHS Choices. Symptoms - Irritable bowel syndrome (IBS) [Internet]. 2024 [cited 2024 Feb 1]. Available from: https://www.nhs.uk/conditions/irritable-bowel-syndrome-ibs/symptoms/

14. NHS Choices. Diet, lifestyle and medicines - Irritable bowel syndrome (IBS) [Internet]. 2024 [cited 2024 Feb 1]. Available from: https://www.nhs.uk/conditions/irritable-bowel-syndrome-ibs/diet-lifestyle-and-medicines/

15. NHS Choices. Overview - Coeliac disease [Internet]. 2024 [cited 2024 Feb 1]. Available from: https://www.nhs.uk/conditions/coeliac-disease/

16. NHS Choices. Overview - Ulcerative colitis [Internet]. 2024 [cited 2024 Feb 1]. Available from: https://www.nhs.uk/conditions/ulcerative-colitis/

17. NHS Choices. Overview - Crohn’s disease [Internet]. 2024 [cited 2024 Feb 1]. Available from: https://www.nhs.uk/conditions/crohns-disease/