Several everyday foods can relieve constipation by softening stool, speeding up digestion, or feeding the gut bacteria that keep things moving. The most effective options are high in fiber, natural sugar alcohols, or beneficial bacteria. Most adults need 25 to 34 grams of fiber per day depending on age and sex, and the average person falls well short of that target.
Prunes and Prune Juice
Prunes are the most well-known constipation remedy for good reason. They contain a combination of dietary fiber (particularly pectin), sorbitol, and plant compounds called polyphenols that all work together to draw water into the intestines and soften stool. Sorbitol is a sugar alcohol your body absorbs slowly, so it pulls fluid into the colon the same way an osmotic laxative would, but more gently.
In a Harvard-reviewed study, people who drank prune juice daily reported fewer hard, lumpy stools after just three weeks. By seven weeks, most had regular bowel movements. If you don’t like the texture of whole prunes, the juice works too, though whole prunes deliver more fiber per serving.
Kiwifruit
Green kiwifruit has become one of the most studied foods for constipation in recent years. Two green kiwifruits a day is the dose most clinical trials have used, and the results are consistent: improved stool frequency and softer consistency in people with functional constipation and even constipation-predominant irritable bowel syndrome.
What makes kiwi unusual is an enzyme called actinidin. This protein-digesting enzyme survives the acid environment of your stomach and helps break down food faster, improving gastric emptying time. Combined with kiwi’s fiber and high water content, the effect is a gentle but reliable improvement in gut motility. The green Hayward variety has the strongest evidence behind it, so look for that over gold kiwis if constipation is your goal.
Beans and Lentils
Legumes are fiber powerhouses. One cup of cooked lentils contains about 15.6 grams of fiber, nearly half the daily goal for most adults. Black beans come in at 15 grams per cup, and chickpeas at 12.5 grams. That fiber is a mix of soluble and insoluble types, which means legumes soften stool and add bulk at the same time.
If beans aren’t a regular part of your diet, start with small portions. A quarter cup added to a salad or soup is enough to begin with. Jumping straight to large servings is a reliable recipe for bloating and gas, especially if your gut bacteria aren’t accustomed to processing that much fiber.
How Fiber Actually Works
Not all fiber does the same thing. Insoluble fiber, found in whole wheat, vegetable skins, and nuts, works mechanically. Its particles irritate the gut lining just enough to trigger the release of mucus and water, producing larger, softer stools that move through the colon faster. Think of it as roughage in the most literal sense.
Soluble fiber, found in oats, flaxseeds, and fruits, takes a different approach. It forms a gel that holds onto water and resists the drying effect of the large intestine. The result is stool that stays soft and bulky rather than compacting into hard, difficult-to-pass lumps. Both types matter, and the best anti-constipation diets include a mix of each.
Flaxseeds and Chia Seeds
Ground flaxseeds are one of the simplest additions you can make. The NHS recommends 10 to 15 grams of ground flaxseed mixed with about 150 milliliters of liquid, taken two or three times a day. That’s roughly one tablespoon per serving, stirred into yogurt, oatmeal, or a smoothie. The key word is “ground.” Whole flaxseeds often pass through your system intact, so you miss out on the fiber and the oils inside.
Chia seeds work similarly but come with an important caveat: soak them in water before eating. Dry chia seeds absorb many times their weight in liquid, and if that expansion happens inside your digestive tract rather than in a glass, it can make constipation worse, not better. A 15-minute soak in water or milk turns them into a gel that’s safe and effective.
Fermented Foods
Constipation isn’t just about fiber. The bacteria living in your gut play a direct role in how quickly food moves through, and fermented foods can shift that bacterial balance in a helpful direction.
Kefir has some of the most encouraging data. In a pilot study of 20 patients with constipation, drinking 500 milliliters of kefir daily for four weeks improved stool frequency, stool consistency, and reduced laxative use. The improvement was especially notable in people with slow-transit constipation, the type where everything just seems to crawl through the system.
Sauerkraut also shows promise. In a study of 58 people with IBS, 75 grams of sauerkraut per day (about a third of a cup) for six weeks significantly improved symptom severity scores in both groups tested. Interestingly, both pasteurized and unpasteurized sauerkraut worked, suggesting the fiber and compounds in the cabbage itself contribute alongside the live bacteria. Other fermented options like nattō, a Japanese fermented soybean product, have been linked to increased stool frequency and higher levels of beneficial gut bacteria, though the research is still small-scale.
Other Foods Worth Adding
Beyond the standout performers, several other foods contribute meaningfully to constipation relief:
- Oats: Rich in soluble fiber (beta-glucan), a bowl of oatmeal delivers about 4 grams of fiber and holds moisture well through digestion.
- Pears and apples: Both contain sorbitol and pectin, the same combination that makes prunes effective. Eat them with the skin on for the insoluble fiber bonus.
- Sweet potatoes: A medium sweet potato has about 4 grams of fiber, mostly insoluble, plus it’s easy to prepare and pair with other high-fiber foods.
- Broccoli and leafy greens: These provide insoluble fiber and a compound called sulforaphane that may support healthy gut bacteria populations.
Water Makes Fiber Work
Fiber without adequate fluid can actually make constipation worse. Soluble fiber needs water to form its gel, and insoluble fiber needs water to keep the bulkier stool soft enough to pass. Research on adults with chronic functional constipation found that a daily fiber intake of 25 grams improved stool frequency, but the effect was significantly enhanced when fluid intake reached 1.5 to 2.0 liters per day. That’s roughly six to eight cups of water, though other liquids count too.
If you’re adding more fiber-rich foods to your diet and noticing that things feel more stuck rather than less, insufficient water is the most likely explanation.
How Quickly to Expect Results
Dietary changes don’t work like laxatives. You may notice some improvement within a few days of increasing your fiber and fluid intake, but meaningful, consistent changes in stool frequency and consistency typically take two to three weeks. The prune juice study saw initial improvements at three weeks and full regularity at seven weeks.
The transition period matters too. When fiber has been largely absent from your diet, introducing it gradually gives your gut bacteria time to adjust to the new influx of food. A sudden jump from 10 grams of fiber a day to 30 grams almost guarantees bloating, cramping, and gas. A better approach is adding one new high-fiber food every few days and increasing portions slowly over two to three weeks. Your microbiome adapts, the gas settles down, and the constipation relief becomes more sustainable than anything a one-time laxative can offer.