What Foods Should You Eat to Help With Constipation

Fiber-rich whole foods form the backbone of any diet aimed at relieving constipation, but some specific foods have stronger clinical evidence behind them than you might expect. Prunes, kiwifruit, and flaxseed have each been tested head-to-head against standard laxative treatments and held their own. The bigger picture, though, involves not just what you add to your plate but also what you remove and what you drink alongside it.

Prunes Are the Best-Studied Single Food

If you ask a gastroenterologist to recommend one food for constipation, prunes are the answer with the longest track record. A randomized trial comparing dried plums to psyllium, a commonly recommended fiber supplement, found that prunes produced significantly more complete spontaneous bowel movements per week and better stool consistency scores.¹ A systematic review of over-the-counter constipation therapies confirmed these results, noting that prunes outperformed psyllium on both bowel movement frequency and stool softness.²

Part of what makes prunes effective is sorbitol, a sugar alcohol that the body absorbs poorly. Because it stays in the intestine, it draws water into the colon through osmosis, making stool softer and easier to pass. Research on sorbitol has shown that it accelerates colonic transit in healthy people within just a few hours.³ Prunes also supply about 7 grams of fiber per 100 grams, along with phenolic compounds that may contribute to their gut-stimulating effects. A handful of five or six prunes a day, roughly 50 grams, is the dose most commonly used in trials.

Kiwifruit Helps With More Than Just Regularity

Kiwifruit is one of the more surprising constipation remedies to come out of clinical research in recent years. A large international trial found that eating two green kiwifruits per day increased bowel movement frequency by about 1.5 additional complete spontaneous movements per week and significantly improved overall gastrointestinal comfort in people with both functional constipation and constipation-predominant irritable bowel syndrome.⁴ A separate trial using gold kiwifruit found similar benefits, with reduced straining alongside more frequent bowel movements.⁵

That comfort finding is worth highlighting. Many fiber-heavy interventions improve frequency but leave people feeling bloated or gassy. In a trial that compared green kiwifruit directly to prunes and psyllium, all three treatments increased bowel movements, but kiwifruit significantly improved stool consistency and reduced straining.⁶ Kiwifruit contains actinidin, an enzyme that aids protein digestion, along with a mix of soluble and insoluble fiber that seems to add bulk without the excess gas some people experience with other high-fiber foods. If prunes are too sweet for your taste or you find their laxative effect too strong, two kiwifruits a day is a gentler approach with solid evidence behind it.

Flaxseed Outperformed a Standard Laxative

Ground flaxseed is an underrated option that deserves more attention. In a randomized trial of people with chronic functional constipation, flaxseed flour increased weekly bowel movements from a median of two to seven, compared to two to six with lactulose, a commonly prescribed osmotic laxative. Quality-of-life scores improved more with flaxseed as well.⁷ Another trial in people with type 2 diabetes and constipation found that flaxseed outperformed psyllium for constipation symptoms and stool consistency, with the added bonus of improving blood sugar and cholesterol levels.⁸

Flaxseed works through a combination of mechanisms. It is high in both soluble and insoluble fiber, and the soluble fiber forms a gel when mixed with water, which adds moisture to stool. It also contains mucilage, a sticky substance that lubricates the intestinal tract. One practical note: whole flaxseeds tend to pass through undigested, so grinding them or buying pre-ground flaxseed meal makes a meaningful difference in how well they work. A tablespoon or two stirred into yogurt, oatmeal, or a smoothie is a simple way to incorporate them daily.

Why the Mix of Fiber Types Matters

Fiber is not one thing. Insoluble fiber, the kind found in wheat bran, vegetable skins, and whole grains, adds bulk to stool and stimulates the intestinal walls to push things along. Soluble fiber, found in oats, beans, citrus fruits, and psyllium husks, absorbs water and forms a gel that softens stool. Both types are useful, but research suggests that using them together works better than relying on one alone.

An experimental study on constipated mice found that when soluble and insoluble fiber were combined at a roughly equal ratio, fecal water content returned to normal levels, the rate at which the stomach emptied improved the most, and the production of short-chain fatty acids in the gut peaked.⁹ Using soluble fiber alone actually reduced gut microbiome diversity in that study, and insoluble fiber alone was less effective at softening stool. The practical takeaway is that variety matters. A diet that includes both wheat bran or vegetables for bulk and oats or beans for moisture is more likely to keep things moving than one that leans heavily on a single fiber source.

Those short-chain fatty acids are worth knowing about. When gut bacteria ferment fiber, they produce compounds, mainly acetate, propionate, and butyrate, that stimulate fluid absorption and blood flow in the colon.¹⁰ These byproducts also promote colonic muscle contractions, which is how a high-fiber diet supports the physical movement of waste through the intestine. Foods that feed your gut bacteria, like legumes, oats, and resistant starch from cooled potatoes or green bananas, are doing double duty: adding bulk and fueling the microbial activity that keeps the colon contracting.

Coffee Stimulates the Colon, Not Just Your Brain

Many people notice that their morning coffee sends them to the bathroom, and research confirms this is a real physiological effect rather than just a habit or placebo. A study measuring colonic pressure found that both caffeinated and decaffeinated coffee stimulated significantly more colon activity than water, with more propagated contractions that push stool forward.³ Another study found that coffee increased motility in the distal colon within four minutes of drinking it, and the effect lasted at least 30 minutes, though only in about 60 percent of participants.¹¹

The fact that decaf coffee also triggers this response means caffeine is not the whole story. Coffee contains hundreds of bioactive compounds, and researchers suspect that chlorogenic acids and other compounds stimulate the release of gastrin and cholecystokinin, hormones that prompt colonic contractions. Coffee is not a treatment for chronic constipation in the way prunes or kiwifruit are, but if you already drink it and you are looking for a gentle nudge, having a cup in the morning on an empty stomach is a reasonable strategy. Just keep in mind that coffee is a mild diuretic, so you should drink water alongside it to avoid working against the hydration your colon needs.

Fermented Foods and Gut Bacteria

The bacteria living in your colon play an active role in how efficiently waste moves through. Fermented foods can shift that microbial community in ways that improve transit time. A pilot study on kefir found that it accelerated colonic transit and improved bowel satisfaction scores in people with chronic constipation.¹² A separate review of fermented dairy found that fermented milk containing specific probiotic strains reduced both mouth-to-cecum and colonic transit times in people with constipation-predominant IBS, while also lowering overall symptom severity.¹³

Yogurt, kefir, sauerkraut, kimchi, and miso are all reasonable options. The evidence is strongest for fermented dairy products containing live cultures, partly because those have been studied more thoroughly. If you are lactose intolerant, fermented dairy tends to be better tolerated than fresh milk because the bacteria have already broken down much of the lactose. Non-dairy fermented foods have fewer clinical trials behind them for constipation specifically, but they still contribute beneficial bacteria and fermentable substrates to the gut.

Hydration Makes Fiber Work

Eating more fiber without drinking enough water is one of the most common reasons people feel worse instead of better when they change their diet. Fiber absorbs water, and if there is not enough fluid available, the added bulk can actually slow things down and cause bloating. A study of adults with chronic functional constipation found that a daily fiber intake of about 25 grams increased stool frequency on its own, but the effect was significantly enhanced when fluid intake was increased to 1.5 to 2 liters per day.¹⁴

Mineral water high in magnesium sulfate has a long history as a constipation remedy, and the laxative effect of magnesium and sulfate has been demonstrated across multiple studies.¹⁵ A clinical trial confirmed that the response to magnesium-rich mineral water correlated with the magnesium sulfate concentration in the water.¹⁶ Foods rich in magnesium, like spinach, pumpkin seeds, and dark chocolate, support the same principle on a gentler scale. Magnesium draws water into the intestine, which is exactly why milk of magnesia works as an over-the-counter laxative.

Foods That Make Constipation Worse

It is not just about what you add. A large study of U.S. adults found that people who ate the most ultra-processed food had roughly double the odds of constipation compared to those who ate the least. Conversely, those who ate the most minimally processed food had about half the odds of constipation.¹⁷ That association held after adjusting for other factors. A review in children and adolescents found similar patterns, with ultra-processed diets linked to a higher prevalence of abdominal pain, bloating, and altered bowel habits.¹⁸

Ultra-processed foods tend to be low in fiber, high in refined carbohydrates, and loaded with emulsifiers and other additives that may disrupt the gut lining and microbiome. Packaged snacks, fast food, sugary cereals, frozen meals, and soft drinks are the main culprits. You do not have to eliminate them entirely, but if constipation is a recurring problem, cutting back on these foods while increasing whole grains, fruits, vegetables, and legumes addresses both sides of the equation at once.

Olive Oil and Other Helpful Fats

Dietary fat can act as a natural lubricant for the intestinal tract. Extra virgin olive oil, in particular, has shown laxative properties in a clinical trial comparing it to refined olive oil, with participants who consumed the extra virgin version reporting less difficulty with bowel movements. Researchers attributed the benefit to the polyphenol compounds in extra virgin olive oil, which appear to stimulate large intestine contractions and increase the secretion of water and electrolytes into the gut.¹⁹ A tablespoon of extra virgin olive oil in the morning or drizzled over salad is a traditional Mediterranean approach that now has at least some clinical backing.

Green bananas and resistant starch deserve a mention here too. While ripe bananas are sometimes blamed for worsening constipation (because they are lower in fiber and higher in sugar than their green counterparts), the resistant starch in unripe bananas has been shown in animal studies to accelerate gastrointestinal movement and shorten the time to first bowel movement.²⁰ Resistant starch acts more like fiber than like a typical starch. It resists digestion in the small intestine and reaches the colon intact, where bacteria ferment it into those beneficial short-chain fatty acids. Cooled cooked potatoes, cooked and cooled rice, and legumes are other good sources of resistant starch.

When Diet Alone Is Not Enough

Dietary changes help most people with garden-variety constipation, but there are forms of the condition where food alone will not solve the problem. Slow-transit constipation, where the colon’s nerves do not contract effectively, and pelvic floor dysfunction, where the muscles involved in defecation do not coordinate properly, often require medical treatment beyond dietary fiber. A review of nutritional care for constipation noted that fiber and psyllium may be effective for people without slow colonic transit or disordered defecation, essentially drawing a line around who benefits most from dietary intervention.²¹

For people with irritable bowel syndrome, the relationship between fiber and symptoms is more complicated. A systematic review found that fiber was beneficial in most studies of chronic constipation and constipation-predominant IBS, but the results were inconsistent, and a low-FODMAP diet improved overall IBS symptoms in the majority of studies that tested it.²² FODMAPs are short-chain carbohydrates that ferment rapidly in the gut, and for some people with IBS, reducing them brings more relief than adding fiber does. If increasing fiber makes your bloating and discomfort worse rather than better, that is a signal worth discussing with a doctor rather than simply pushing through.

Constipation During Pregnancy

Constipation affects a large proportion of pregnant women, driven by hormonal changes that slow gut motility and, later in pregnancy, physical compression of the intestine by the growing uterus. Higher fiber intake during pregnancy has been associated with reduced constipation along with other benefits like more appropriate weight gain and lower risk of gestational glucose intolerance.²³

A Cochrane review of interventions for constipation in pregnancy found that fiber supplements increased defecation frequency and led to softer stools.²⁴ Bran and wheat fiber were the most studied forms. However, the evidence base is thin, with only a small number of suitable trials available. For pregnant women, dietary fiber from fruits, vegetables, and whole grains is the safest first step. Many of the foods discussed earlier, like prunes, kiwifruit, and ground flaxseed, are generally considered safe in pregnancy at typical food-level servings, though it is worth checking with a provider before starting any concentrated supplement form.

A Practical Grocery List

Pulling this together into something actionable, here are the foods with the strongest evidence or most plausible mechanisms for easing constipation:

Prunes: five to six daily, the most-studied single food for constipation relief
Kiwifruit: two per day, effective and gentler on digestion than many high-fiber options
Ground flaxseed: one to two tablespoons daily, mixed into food rather than eaten whole
Psyllium husk: a soluble fiber supplement that traps water in the intestine and eases defecation²⁵
Legumes and oats: reliable sources of soluble fiber that feed gut bacteria
Vegetables and whole grains: provide the insoluble fiber that adds bulk
Extra virgin olive oil: a tablespoon daily may lubricate the tract and stimulate contractions
Kefir or live-culture yogurt: fermented dairy that can speed up colonic transit
Green bananas and cooled potatoes: sources of resistant starch that works like fiber in the colon

Increase fiber gradually over a week or two rather than all at once, and match each increase with more water. A sudden jump in fiber intake without adequate fluid is the recipe for the bloating and cramping that make people give up on dietary changes before they have a chance to work.