Constipation is one of the most common digestive complaints in the UK — the NHS estimates that it affects around one in seven adults at any given time, and significantly more experience it intermittently. Despite being common, constipation is frequently mismanaged through an over-reliance on laxatives and insufficient attention to the dietary factors that drive and maintain the condition. This guide covers the evidence-based dietary approaches that genuinely improve bowel regularity.
Understanding What Causes Constipation
Constipation occurs when stool moves too slowly through the large intestine, allowing excessive water reabsorption and producing hard, difficult-to-pass stools. The causes are varied: inadequate dietary fibre, insufficient fluid intake, low physical activity, certain medications (particularly opioids, iron supplements, and some antidepressants), ignoring the urge to defecate, and underlying medical conditions including hypothyroidism and bowel structural issues. Diet addresses the modifiable lifestyle causes — fibre, fluid, and the quality of the gut microbiome that influences motility.
Fibre: Type Matters as Much as Quantity
The NHS recommends 30g of dietary fibre daily for adults, yet average UK intake is approximately 20g. Increasing fibre intake reliably improves constipation — but the type of fibre matters. Insoluble fibre (from wheat bran, vegetables, and whole grains) adds bulk to stool and speeds transit. Soluble fibre (from oats, fruit, legumes, and psyllium husk) forms a gel that softens stool and feeds beneficial bacteria that produce gas and short-chain fatty acids stimulating motility.
Increasing fibre gradually is essential — a sudden large increase in fibre intake causes bloating and discomfort as the gut microbiome adjusts. Add 5g extra fibre per week until reaching the 30g target, and always increase water intake alongside fibre increases. The British Dietetic Association has detailed guidance on practical fibre increasing strategies.
Hydration: The Underappreciated Factor
Fibre increases without corresponding fluid increases can actually worsen constipation — fibre needs water to function effectively. Most UK adults are mildly dehydrated on a chronic basis. Targeting 6–8 glasses (1.5–2 litres) of fluid daily, primarily water, directly supports stool hydration and ease of passage. Coffee and tea count toward fluid intake and have additional motility-stimulating effects (caffeine is a mild laxative for many people).
Specific Foods With Evidence for Constipation
Prunes and prune juice — the most well-evidenced food for constipation. Prunes contain sorbitol (an osmotic agent that draws water into the bowel), dihydroxyphenyl isatin (a motility stimulant), and fibre. Two to three prunes daily has consistent evidence for improving stool frequency and consistency. Kiwi fruit — two kiwis daily showed significant improvement in constipation in randomised controlled trials, comparable to psyllium supplementation. Flaxseed — ground flaxseed (not whole, which passes through undigested) provides a good source of both soluble and insoluble fibre with specific evidence for constipation relief.
Movement and Physical Activity
Physical activity directly stimulates gut motility — this is one of the reasons that sedentary desk-based work is associated with higher rates of constipation. Even moderate movement (walking, cycling, taking the stairs) stimulates the muscular contractions that move stool through the large intestine. For London office workers with largely sedentary working days, the activity level outside working hours and movement breaks during the day have a direct impact on bowel regularity.
For comprehensive gut health support, see our microbiome diversity guide and our complete fibre and digestive health guide. If constipation persists despite dietary changes, consult your GP — the NHS constipation guidance covers when to seek medical advice.
Supporting Your Health Through Daily Nutrition
Understanding the principles covered in this article is valuable — but applying them consistently through daily food choices is where the real benefit comes. For London office workers, the quality of the daily work lunch is one of the most controllable nutritional variables in the day. A fresh, balanced, nutritious lunch delivered to your desk removes one decision from a demanding schedule and ensures a consistently good nutritional foundation.
Vanda's Kitchen near St Paul's Cathedral EC4 delivers certified halal, 100% nut-free, freshly prepared corporate catering across the City of London and central London. Our Filipino-inspired menu is built around lean proteins, fresh vegetables, and complex carbohydrates — the nutritional combination that supports energy, performance, and health throughout the working day. Every item we produce carries full allergen labelling in compliance with Natasha's Law, and our entire kitchen is independently certified halal by the Halal Friendly List.
Our Selfridges Food Hall presence confirms the quality standard we maintain. For London teams wanting consistently nutritious, genuinely delicious, allergen-safe daily lunches, Vanda's Kitchen is the straightforward answer. View our team lunch options, WhatsApp us for a same-day response, or send an enquiry. Read our healthy office lunch delivery guide for more on what we offer and how our delivery works.
Frequently asked questions
How long does it take for dietary changes to improve constipation?
Most people notice improved stool frequency and consistency within three to seven days of increasing fibre and fluid intake, provided the increase is gradual. Sudden large fibre increases can temporarily worsen bloating before improving regularity as the gut microbiome adjusts. Consistent dietary changes over two to four weeks produce more reliable and sustained improvement than short-term interventions.
Is it normal to feel more bloated when I increase fibre for constipation?
Yes, and it is expected. Increased fibre fermentation by gut bacteria produces more gas as the microbiome adapts to a higher-fibre diet. This typically peaks within the first one to two weeks and subsides as the microbial community adjusts. Adding fibre in increments of approximately 5g per week, rather than all at once, significantly reduces this transitional bloating.
Are laxatives safe to use regularly alongside dietary changes?
Bulk-forming laxatives such as psyllium husk are safe for regular use and work alongside dietary fibre. Osmotic laxatives such as lactulose or macrogol are also considered safe for extended use under medical guidance. Stimulant laxatives (senna, bisacodyl) are intended for short-term use — regular dependence can reduce the bowel's own motility signalling over time. Speak to your GP if you are using stimulant laxatives more than occasionally.
Does stress cause constipation?
Yes. The gut and brain are directly connected through the enteric nervous system, and psychological stress activates the sympathetic nervous system, which slows gut motility. This is the physiological basis for constipation worsening during periods of high work pressure or anxiety. Addressing stress through lifestyle approaches — adequate sleep, physical activity, stress management — supports bowel regularity alongside dietary intervention.
How much water should I drink daily to help with constipation?
Six to eight glasses (approximately 1.5-2 litres) of fluid daily is the general recommendation, and water is the most effective choice. All fluids count, including tea and coffee. The key practical rule is that fibre increases must be matched by fluid increases — adding fibre without increasing water can actually worsen constipation by making stool bulkier without the hydration needed for easy passage.