The British Dietetic Association (BDA) has published its first comprehensive evidence-based dietary guidelines for the management of chronic constipation in adults. These guidelines advance prior advice by identifying specific foods, supplements and drinks supported by clinical trials, rather than only general recommendations such as “eat more fibre”.1
Chronic constipation is generally defined as unsatisfactory defecation characterised by infrequent stools, difficult stool passage or both. It may impact quality of life by causing abdominal pain, bloating, reduced activity and mood‐related effects. 1
While occasional constipation is common, persistent symptoms lasting months—with or without obvious causes—warrant medical and dietary attention.
Previous clinical guidance focused largely on increasing dietary fibre and fluid intake, often without detailed specifics about which foods or supplements worked best. The new BDA guidelines are based on a systematic review of 75 randomized controlled trials (RCTs), resulting in 59 recommendation statements graded by strength and certainty using the GRADE framework. This marks an important shift toward more nuanced, diet-centred management of constipation.
The guidelines highlight several practical dietary strategies:
Foods: Regular consumption of 2–3 kiwifruits per day showed benefit in trials. Rye bread and prunes were also identified as useful food options.
Supplements and drinks: Fibre supplements such as psyllium (>10 g/day) over at least 4 weeks improved stool frequency and consistency. Probiotics, magnesium oxide supplements and high-mineral water were also included among recommendation statements.
General fibre target: Although generic high-fibre diets lacked conclusive evidence for constipation management within these guidelines, the BDA reiterates the adult target of about 30 g dietary fibre per day for overall health.
Fluid intake: Adequate fluid intake remains a key component because dietary fibre adds bulk and requires fluid to aid stool transit. 1
From a practical perspective, adults with chronic constipation may adopt the following apart from the above recommendations:
Ensure daily fluid intake of at least 1.5–2 litres (or more if additional fibre intake is increased).
Include probiotic‐rich foods (such as yoghurt with specified strains) if suitable.
Maintain regular meal times and ensure physical activity, as movement supports gut motility.
The guidelines emphasise that dietary changes should be gradual—rapid large increases in fibre may provoke wind, bloating or discomfort, especially in individuals with slower gut transit or sensitive abdomen.
The BDA paper and other clinical resources emphasise that diet alone may not suffice for all individuals. If constipation persists despite dietary and fluid changes, or if symptoms include rectal bleeding, unexplained weight loss or a sudden change in bowel habit, consultation with a healthcare professional is essential. Moreover, structural causes, medications, neurological disorders and pelvic floor dysfunction may require specialist assessment or treatment.
For dietitians, gastroenterologists and general practitioners, the new BDA guidelines provide a structured tool for diet-based intervention, shifting part of management upstream from pharmacologic treatments. For patients, the guidance offers more defined options and foods rather than generic “eat more fibre” advice.
The British Dietetic Association’s new evidence-based dietary guidelines for chronic constipation recommend fiber-rich foods like kiwifruit, prunes, psyllium, and whole grains, along with proper hydration, to naturally improve gut and bowel health.
It is important to acknowledge that these guidelines apply primarily to adults with chronic primary constipation (i.e., not secondary to other conditions) and that individual responses vary. The guidelines caution that some widely used strategies, like senna supplements or unlabeled high-fibre diets, do not have sufficient evidence for strong recommendations in this context.
In addition, other lifestyle factors such as insufficient exercise, low physical activity, low fluid intake and low fibre intake are known risk factors for constipation and may require concurrent attention.
References
British Dietetic Association. “The BDA’s First Evidence-Based Dietary Guidelines for Chronic Constipation Are Now Available.” October 13, 2025. Accessed October 21, 2025. https://www.bda.uk.com/resource/the-bda-s-first-evidence-based-dietary-guidelines-for-chronic-constipation-are-now-available.html.
British Dietetic Association. “Fibre.” April 2021; review date April 2024. Accessed October 21, 2025. https://www.bda.uk.com/resource/fibre.html.
(Rh/Eth/TL)