Constipation Despite Eating Well: What Could Be Missing?
Quick answer: If you eat well and are still constipated, the missing piece is often not more fibre. It may be the type of fibre, not enough fluid alongside it, ignoring the urge to go, sitting in a position that makes emptying harder, too little movement, a medication or supplement that slows the bowel, low thyroid function, a pelvic floor that does not relax properly, or a slow-moving gut linked to methane-producing microbes. Each of these needs a different approach.
- Fibre works best with enough fluid; in one trial, adding water boosted its effect.
- Kiwifruit, prunes and psyllium have the best evidence among foods and fibres.
- A footstool and an unhurried morning routine help more than people expect.
- Straining despite soft stools may point to the pelvic floor, which needs a specialist.
Some of the most frustrated clients I see in sessions are people who are constipated despite "doing everything right". They eat vegetables at every meal, choose wholegrains, drink their water, and still go every two or three days, with a lot of effort and a feeling of never quite finishing.
I have written before about the root causes of chronic constipation. This article is for the specific situation where the diet already looks good on paper, and focuses on what is often missing. If bloating comes along with it, you may also want to read whether too much fibre can make bloating worse.
Why can you be constipated on a healthy diet?
Bowel movements depend on much more than fibre. The gut needs the right type of fibre, enough water to soften stool, regular muscle contractions to move it along, a nervous system relaxed enough to allow digestion, a daily cue to go, and a pelvic floor that relaxes at the right moment. A healthy plate covers only the first of these. When constipation persists, one of the others is usually the weak link.
8 things that are often missing
1. Enough fluid with your fibre
Soluble fibre works by holding water and forming a soft gel, so it works best when you drink enough. In one trial, people with constipation on a high-fibre diet had more frequent bowel movements when they also drank 1.5 to 2 litres of water a day [1].
2. The right type of fibre
Coarse wheat bran and lots of raw salad add bulk but can increase bloating. Soluble fibre, particularly psyllium, has the strongest evidence for improving stool frequency and consistency in chronic constipation [2]. If your fibre comes mainly from bread, cereals and salad, shifting some of it towards psyllium, oats, kiwi, cooked vegetables and soaked chia or flaxseed often helps.
3. Two kiwis or a few prunes a day
Some foods have specific evidence. In a comparative trial, two green kiwifruit a day improved complete bowel movements as well as psyllium and prunes did, and were the best tolerated, with less bloating [3]. Prunes have also been shown to increase stool frequency and improve consistency, likely because of their sorbitol and polyphenol content as well as fibre [4]. Prunes can bloat people who are sensitive to polyols, so kiwi is often the gentler first choice.
4. A daily routine and responding to the urge
The bowel tends to become more active soon after waking, and again after meals, especially breakfast, through a reflex known as the gastrocolic reflex. Rushing out of the door, skipping breakfast, or regularly holding on until you are home teaches the bowel to ignore its signals. Giving yourself ten unhurried minutes after breakfast, at roughly the same time each day, is a simple but powerful habit.
5. How you sit on the toilet
Raising your knees above your hips straightens the angle between the rectum and the anal canal, which makes emptying easier. In a study of healthy volunteers, using a footstool reduced straining and time on the toilet and improved the feeling of complete emptying [5]. Lean forward slightly, rest your elbows on your knees, relax your belly and breathe out rather than holding your breath.
6. Movement and magnesium
Physical activity stimulates gut motility, and long periods of sitting slow it down. A daily walk, ideally after a meal, makes a difference for many people. Magnesium salts, such as those found in some mineral waters and supplements, draw water into the bowel; in one trial in women with functional constipation, drinking a litre a day of a magnesium sulphate-rich mineral water improved stool frequency [6]. Magnesium-rich foods such as leafy greens, pumpkin seeds, almonds and buckwheat are worth including for overall intake, although they do not act as a laxative in the same way.
7. Medications, supplements and underlying conditions
Several common medications and supplements slow the bowel: iron tablets, calcium, some antidepressants, antihistamines, opioid painkillers, some blood pressure tablets and antacids containing aluminium. Never stop a medication yourself, but it is worth asking your doctor or pharmacist whether yours may be contributing. Low thyroid function, high calcium levels, diabetes and pregnancy can all slow the gut too, which is why a blood test with your GP is a sensible step if constipation is new or persistent [7].
8. The pelvic floor and a slow-moving gut
Some people produce soft stools but still struggle to pass them, need to strain a lot, or feel a blockage. This may be dyssynergic defecation, where the pelvic floor muscles tighten instead of relaxing when you try to go. It is common, often missed, and responds well to specialist pelvic floor physiotherapy and biofeedback [8].
Others have slow transit throughout the gut. In some of these people, an overgrowth of methane-producing microbes plays a part: methane slows intestinal transit in animal studies, and in people higher methane levels are linked with slower transit [9]. This pattern often comes with bloating and is one reason I look at the gut as a whole, including the possibility of SIBO or intestinal methanogen overgrowth.
Which piece might be missing for you?
| If this sounds like you | Look first at |
|---|---|
| Hard, dry, pellet-like stools | Fluid intake, soluble fibre, kiwi, magnesium-rich mineral water |
| Soft stools but a lot of straining or incomplete emptying | Toilet posture, breathing, pelvic floor assessment |
| Rarely feel the urge | Morning routine, breakfast, movement, slow transit |
| Constipation plus significant bloating | Fibre type and pace, methane-related patterns, SIBO |
| Started with a new medication or supplement | Speak to your doctor or pharmacist |
| Also tired, cold, dry skin, hair loss | Ask your GP to check thyroid function and iron |
A practical starting point
- Eat two green kiwis a day, for example with breakfast, for four weeks.
- Drink a large glass of water on waking and with each meal.
- Have a warm breakfast and then allow ten unhurried minutes for the toilet.
- Use a footstool and breathe out gently rather than straining.
- Walk for 10 to 20 minutes after at least one meal a day.
- Consider psyllium, starting with half a teaspoon in a full glass of water and increasing slowly.
- Track your bowel movements using the Bristol Stool Chart in a food and symptom diary, so you can see what is changing.
When to see your doctor first
See your GP promptly if constipation is a new and persistent change, particularly over the age of 50, or if it comes with blood in or on your stool, black stools, unintentional weight loss, anaemia, severe or worsening abdominal pain, vomiting, being unable to pass wind, or a family history of bowel cancer or inflammatory bowel disease. Also ask your doctor before using laxatives long term.
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Book your free 15-minute call →Frequently asked questions
Why am I constipated even though I eat a lot of fibre?
Common reasons include not drinking enough fluid with the fibre, relying on coarse insoluble fibre, ignoring the urge to go, sitting in a position that makes emptying harder, low activity, medications or supplements such as iron, low thyroid function, a pelvic floor that does not relax properly, or slow gut transit.
Do kiwis really help with constipation?
Yes. In a comparative trial, two green kiwifruit a day improved bowel movements about as well as psyllium and prunes and caused less bloating. Give it around four weeks.
Can drinking more water help constipation?
It helps mostly when combined with fibre. Fibre needs water to soften the stool; drinking more water on its own has a smaller effect if you are already well hydrated.
Does using a footstool on the toilet really work?
For many people, yes. Raising the knees above the hips straightens the rectum and has been shown to reduce straining and improve the feeling of complete emptying.
What if I strain even when my stools are soft?
That can be a sign that the pelvic floor muscles are not relaxing properly when you try to go. Speak to your doctor about referral to a pelvic floor physiotherapist, who can assess this and teach techniques that help.
Can I work with you online if I am not in Lisbon?
Yes. I see clients in person in Lisbon and Estoril and online, in English, Portuguese, Spanish and French. You can start with a free 15-minute discovery call.
References
- Anti M, Pignataro G, Armuzzi A, et al. Water supplementation enhances the effect of high-fiber diet on stool frequency and laxative consumption in adult patients with functional constipation. Hepato-Gastroenterology. 1998;45(21):727–732. PubMed
- van der Schoot A, Drysdale C, Whelan K, Dimidi E. The effect of fiber supplementation on chronic constipation in adults: an updated systematic review and meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition. 2022;116(4):953–969. PubMed
- Chey SW, Chey WD, Jackson K, Eswaran S. Exploratory comparative effectiveness trial of green kiwifruit, psyllium, or prunes in US patients with chronic constipation. American Journal of Gastroenterology. 2021;116(6):1304–1312. PubMed
- Lever E, Cole J, Scott SM, Emery PW, Whelan K. Systematic review: the effect of prunes on gastrointestinal function. Alimentary Pharmacology & Therapeutics. 2014;40(7):750–758. PubMed
- Modi RM, Hinton A, Pinkhas D, et al. Implementation of a defecation posture modification device: impact on bowel movement patterns in healthy subjects. Journal of Clinical Gastroenterology. 2019;53(3):216–219. PubMed
- Dupont C, Campagne A, Constant F. Efficacy and safety of a magnesium sulfate-rich natural mineral water for patients with functional constipation. Clinical Gastroenterology and Hepatology. 2014;12(8):1280–1287. PubMed
- NICE Clinical Knowledge Summaries. Constipation. cks.nice.org.uk/topics/constipation
- Rao SSC, Bharucha AE, Chiarioni G, et al. Functional anorectal disorders. Gastroenterology. 2016;150(6):1430–1442. PubMed
- Pimentel M, Lin HC, Enayati P, et al. Methane, a gas produced by enteric bacteria, slows intestinal transit and augments small intestinal contractile activity. American Journal of Physiology – Gastrointestinal and Liver Physiology. 2006;290(6):G1089–G1095. PubMed
This article is for educational purposes and is not medical advice. Always work with your doctor for diagnosis and before making changes to your care.