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Newsletter · Issue 3 · October 2026

Kiwifruit, prunes and a footstool: what the trials say about chronic constipation.

A common problem, and more responsive to food than most people are told.

About one adult in seven lives with chronic constipation1. Most are told to eat more fiber and drink more water, and then left to work out the rest. This issue is about the rest: what counts as constipation; what the trials found for fruit, fiber and fluid; the habits that cost nothing; what to skip; and the signs that mean a doctor rather than a diet change.

Illustration of the large intestine with the food, fluid and routine changes that help labeled around it, and the warning signs that need a doctor first
What helps, and the signs that need a doctor first. From the chronic constipation guide.

It is not only about how often you go

Three bowel movements a week is within the normal range. What matters is whether passing stool is hard work: straining, hard or lumpy stools, the feeling of not having finished. Many people who go every day are constipated by that definition. The shape of the stool says more than the count, and hard, separate lumps mean stool is moving slowly through the colon2.

⚠️ Check the red flags first. See a doctor promptly, rather than trying diet first, if you have blood in or on the stool, weight loss you did not intend, constipation that is new after the age of fifty, a change in bowel habit that lasts more than a few weeks, iron-deficiency anemia or a family history of colorectal cancer. Call 911 or go to the emergency department for severe abdominal pain with vomiting, a swollen abdomen or being unable to pass gas at all315.

Check your medicines too

Opioid pain relievers, iron and calcium supplements, some antacids, several antidepressants and some blood pressure medicines all slow the bowel3. Ask your prescriber before stopping or changing any of them.

What the trials found

Fruit did as well as fiber supplements, or better

Two green kiwifruit a day added about one and a half complete bowel movements a week in a large international trial4. Prunes, about ten to twelve a day split into two servings, did better than psyllium in a crossover trial5. In a US trial that compared all three, kiwifruit had the fewest side effects6. Eat the fruit whole: juice leaves the fiber behind.

Fiber works, slowly and with water

Across sixteen trials, 66% of people responded to fiber supplements against 41% on control, with psyllium the best supported and the benefit at more than 10 g a day taken for at least four weeks7. Raise fiber from legumes, oats, whole grains, vegetables and whole fruit over two to three weeks, because a sudden jump causes the gas and bloating that make people give up. And drink with it: in one trial, people eating the same fiber who drank about 2 quarts (2 liters) a day had more bowel movements and used fewer laxatives than those who drank about 1 quart (1 liter)8.

Habits that cost nothing

A regular time, usually after breakfast, when the colon is naturally most active, and going as soon as you feel the urge3. Feet raised on a small footstool, knees above hips, which in a crossover study reduced straining and time on the toilet and improved the sense of emptying9. And daily movement, walking included.

When fiber is the wrong tool

Fiber bulks up the stool, which is what helps when the problem is slow transit. It does not help a pelvic floor that tightens when it should relax, and more bulk behind that kind of problem can mean more bloating and straining. If fiber has made things worse, tell your clinician: a pelvic floor problem is found by testing and retrained with biofeedback, which laxatives do not replace3.

What to skip

"Detox" teas, colon cleanses and herbal laxative blends are not treatments for constipation. Many herbal teas contain senna at an unlabeled dose, which makes cramping and reliance on the product more likely, not less. Colon cleansing is not supported by evidence, and it can have serious side effects10. Probiotics are not a first step either: results vary between trials and strains, and a result for one product cannot be assumed for another11. If you try one and it makes no difference, stop it.

Laxatives are not a failure

When food and habits are not enough, an osmotic laxative such as polyethylene glycol or magnesium oxide is the usual next step, chosen with a pharmacist or clinician12. Many people avoid stimulant laxatives because they fear a "lazy bowel." A 2024 review found no convincing evidence that they cause lasting damage at normal doses, and one of its authors worked for a laxative manufacturer, a conflict of interest worth weighing13. Avoid magnesium laxatives with reduced kidney function unless your clinician advises otherwise14.

💡 Where the real leverage is. Two kiwifruit or ten to twelve prunes a day, fiber raised slowly with enough water, a regular time after breakfast and your feet on a stool. All of it costs little, and all of it has better evidence than anything sold as a cleanse.

Read the chronic constipation guide →

If you live with a related condition

Straining is a main cause of hemorrhoids and anal fissures, and it worsens pelvic organ prolapse. If abdominal pain eases when you go, read the IBS & IBD guide. Constipation is also common in diverticular disease, Parkinson's disease and multiple sclerosis.

Not sure where to start?

The free symptom checker covers every guide in the library. Check what applies and it shows the guides worth reading, with the warning signs that need a doctor, not a website, placed first.

Try the symptom checker →

Also This Month

What else is happening

Not recommended, said plainly

Where a guide's own trial found that a supplement did no better than placebo, the guide now says "Not recommended" for that condition, with the dose the trial used, instead of printing a dose to take. The change went through the whole library, and the site's chat assistant now gives the same answer.

Coming in November

November is Diabetes Awareness Month, and World Diabetes Day is November 14. The November issue takes a full look at prediabetes: what it is, why most people who have it do not know and what the trials say about turning it around.

Scholarships

Root & Restore is a young nonprofit and the scholarship fund is still being built, from donations, for students from low-income households in the US and from least developed or low-income countries who want to study nutrition. Applications will open once the fund is secured.

Free, always

No products, no paywall, no sponsored content. Root & Restore Nutrition Education is a 501(c)(3) nonprofit, and the library stays free because readers keep it that way. If this issue was useful, a donation goes to keeping the guides free and to the scholarship fund.

References & Evidence Notes

The trials and reviews behind this issue, the same ones the chronic constipation guide cites. This newsletter is nutrition education, not medical advice, and it does not replace your doctor.

  1. Suares NC, Ford AC. Prevalence of, and risk factors for, chronic idiopathic constipation in the community: systematic review and meta-analysis. Am J Gastroenterol. 2011;106(9):1582-⁠1591. PubMed 21606976. Forty-five studies and over 261,000 people; pooled prevalence 14%, higher in women, older people and those of lower socioeconomic status. ↩
  2. Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time. Scand J Gastroenterol. 1997;32(9):920-⁠924. PubMed 9299672. The origin of the Bristol stool form scale, showing that stool form tracks how long stool takes to pass through the gut. ↩
  3. On causes, self-care and when to see a doctor: the US National Institute of Diabetes and Digestive and Kidney Diseases lists slow transit, pelvic floor disorders, low fiber, fluid and activity, routine changes, several medicines and supplements, and conditions such as hypothyroidism, diabetes, celiac disease and Parkinson's disease as causes; it advises fiber with fluid, a regular time after breakfast, biofeedback for pelvic floor problems and a prescription medicine when self-care fails; it lists bleeding, constant pain, inability to pass gas, vomiting, fever or weight loss as warning signs, NIDDK, symptoms and causes of constipation and NIDDK, treatment for constipation. ↩
  4. Gearry R, et al. Consumption of 2 green kiwifruits daily improves constipation and abdominal comfort: results of an international multicenter randomized controlled trial. Am J Gastroenterol. 2023;118(6):1058-⁠1068. PubMed 36537785. A crossover trial against psyllium in functional constipation and IBS with constipation; kiwifruit added about 1.5 complete bowel movements a week. Several authors were employed by a kiwifruit marketing company, which a reader should know. ↩
  5. Attaluri A, et al. Randomised clinical trial: dried plums (prunes) vs. psyllium for constipation. Aliment Pharmacol Ther. 2011;33(7):822-⁠828. PubMed 21323688. A single-blind crossover trial giving about 1.8 oz (50 g) of prunes twice a day against psyllium at matched fiber; the authors concluded prunes were more effective for mild to moderate constipation. A small trial. ↩
  6. Chey SW, et al. Exploratory comparative effectiveness trial of green kiwifruit, psyllium, or prunes in US patients with chronic constipation. Am J Gastroenterol. 2021;116(6):1304-⁠1312. PubMed 34074830. Seventy-nine patients, partially randomized; all three improved complete bowel movements, and kiwifruit had the fewest adverse events and the least dissatisfaction. Exploratory, and not powered to show one better than another. ↩
  7. van der Schoot A, et al. The effect of fiber supplementation on chronic constipation in adults: an updated systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr. 2022;116(4):953-⁠969. PubMed 35816465. Sixteen trials, 1,251 participants; 311 of 473 responded to fiber against 134 of 329 on control. Psyllium and pectin showed significant effects, with benefit at doses above 10 g a day and durations of at least four weeks. Flatulence was more common with fiber, and the trials varied considerably. ↩
  8. Anti M, et al. Water supplementation enhances the effect of high-fiber diet on stool frequency and laxative consumption in adult patients with functional constipation. Hepatogastroenterology. 1998;45(21):727-⁠732. PubMed 9684123. 117 patients on about 25 g of fiber a day; those drinking about 2.2 quarts (2.1 liters) a day had more bowel movements and used fewer laxatives than those drinking about 1.2 quarts (1.1 liters). An older trial, but the only randomized test of fluid with fiber. ↩
  9. Modi RM, et al. Implementation of a defecation posture modification device: impact on bowel movement patterns in healthy subjects. J Clin Gastroenterol. 2019;53(3):216-⁠219. PubMed 30346317. Fifty-two volunteers; a footstool reduced straining and time on the toilet and improved emptying. The participants were healthy volunteers rather than people with chronic constipation. ↩
  10. On detoxes and colon cleanses: the NIH National Center for Complementary and Integrative Health reports that a 2015 review found no compelling research behind "detox" diets, that there is insufficient evidence for colon cleansing, and that colon cleansing procedures may have side effects, some of them serious, NCCIH. ↩
  11. Deng X, et al. Network meta-analysis of probiotics, prebiotics, and synbiotics for the treatment of chronic constipation in adults. Eur J Nutr. 2024;63(6):1999-⁠2010. PubMed 38693449. Thirty-seven trials of 21 different products. The evidence for individual probiotic strains was of low to very low certainty, and effects are strain specific and cannot be assumed for another product. ↩
  12. Chang L, et al. American Gastroenterological Association and American College of Gastroenterology clinical practice guideline: pharmacological management of chronic idiopathic constipation. Am J Gastroenterol. 2023;118(6):936-⁠954. PubMed 37204227. Strong recommendations for polyethylene glycol and sodium picosulfate; conditional recommendations for fiber, lactulose, senna and magnesium oxide. ↩
  13. Whorwell P, et al. Review article: do stimulant laxatives damage the gut? A critical analysis of current knowledge. Ther Adv Gastroenterol. 2024;17. PubMed 38887508. A review of 43 publications finding no convincing evidence that stimulant laxatives at therapeutic doses damage the gut or cause colon cancer. One author was employed by a manufacturer of stimulant laxatives. ↩
  14. Mori H, Tack J, Suzuki H. Magnesium oxide in constipation. Nutrients. 2021;13(2):421. PubMed 33525523. A review concluding that magnesium oxide is low cost and generally safe, but that its use should take account of dose, blood magnesium levels, drug interactions and side effects, especially in older people and those with reduced kidney function. ↩
  15. On when abdominal pain is an emergency: MedlinePlus advises calling 911 or the local emergency number for anyone with abdominal pain who is unable to pass stool, especially if they are also vomiting, or who has sudden, sharp abdominal pain or a belly that is rigid and hard to the touch, MedlinePlus, abdominal pain. ↩