White rice can contribute to constipation, especially when it makes up a large portion of your diet. A cup of cooked white rice contains less than 1 gram of fiber, so relying on it as a staple crowds out higher-fiber foods your digestive system needs to keep things moving. Brown rice, on the other hand, is significantly higher in fiber and generally does not have the same effect.
Why White Rice Slows Digestion
White rice is milled to remove the bran and germ, stripping away most of its fiber. What remains is almost pure starch, specifically a type called amylopectin that your body breaks down quickly and absorbs high in the digestive tract. That means very little bulk reaches your colon, and bulk is exactly what your colon needs to form soft, easy-to-pass stools.
Insoluble fiber, the kind found in whole grains, absorbs water and swells in the intestine. This creates a larger, softer stool that moves through faster. Without it, stool sits longer in the colon, where more water gets absorbed, making it harder and more difficult to pass. White rice doesn’t cause this problem on its own in small amounts, but when it replaces fiber-rich foods meal after meal, the cumulative effect adds up.
This is also why white rice is part of the BRAT diet (bananas, rice, applesauce, toast), which doctors have traditionally recommended for diarrhea. Harvard Health describes plain white rice as a bland, low-fiber food that’s easy to digest. That same quality that firms up loose stools during illness can work against you when your digestion is already sluggish.
Brown Rice Works Differently
Brown rice keeps its bran layer intact, which is where most of the fiber lives. A cup of cooked brown rice delivers about 3 to 4 grams of fiber compared to white rice’s fraction of a gram. That bran provides insoluble fiber that holds water in the stool and keeps it moving through the intestine at a healthy pace.
Modified rice bran has even shown therapeutic potential. In a pilot clinical study, a supplement derived from rice bran arabinoxylan (a type of fiber naturally present in the bran) improved both diarrhea and constipation symptoms in people with irritable bowel syndrome. The bran that gets removed to make white rice is, ironically, one of the parts that would prevent the constipation white rice can cause.
Starch Type Matters More Than You’d Think
Not all starch behaves the same way in your gut. White rice is dominated by amylopectin, a rapidly digestible starch. Your small intestine breaks it down almost completely, leaving little for the beneficial bacteria in your lower gut to ferment. Research on starch digestibility has shown that slowly digestible, high-amylose starches increase the flow of nutrients to the lower intestine, boost production of short-chain fatty acids (which feed colon cells), and selectively promote the growth of Bifidobacterium, a beneficial gut microbe. White rice delivers almost none of these benefits because its starch is digested too quickly and too high up in the tract.
There’s a simple kitchen trick that shifts the balance slightly. When you cook white rice and then cool it, some of the starch undergoes a process called retrogradation, converting into resistant starch that your body can’t digest as easily. Freshly cooked white rice contains about 0.64 grams of resistant starch per 100 grams. Cooling it for 10 hours at room temperature nearly doubles that to 1.30 grams. Cooling it for 24 hours in the refrigerator and then reheating it pushes it to 1.65 grams. A clinical study in 15 healthy adults confirmed that the cooled-and-reheated rice also produced a lower blood sugar spike. This won’t transform white rice into a high-fiber food, but it’s a meaningful improvement if white rice is a regular part of your meals.
Rice Cereal and Constipation in Babies
Parents introducing solid foods often start with rice cereal, and constipation is one of the most common complaints that follow. Nationwide Children’s Hospital states directly that rice cereal can cause constipation in some children and recommends switching to oatmeal, wheat, or barley cereal if this happens. Babies have immature digestive systems, and the low fiber content of rice cereal combined with the transition from an all-liquid diet makes them particularly vulnerable to firmer, less frequent stools.
If your baby becomes constipated after starting rice cereal, the fix is usually straightforward: swap to a different grain cereal and see if bowel habits improve within a few days.
How Much Fiber You Actually Need
The U.S. Dietary Guidelines recommend 14 grams of fiber for every 1,000 calories you eat. In practice, that works out to about 25 grams per day for most adult women and 31 to 34 grams per day for most adult men, depending on age. Most Americans fall well short of those targets, and a diet built around refined grains like white rice makes the gap harder to close.
To put it in perspective, you’d need to eat roughly 25 to 30 cups of cooked white rice to hit your daily fiber goal from rice alone. With brown rice, you’d still need 7 or 8 cups, which is why variety matters. Pairing rice with vegetables, legumes, fruits, and other whole grains is the practical path to getting enough fiber without overhauling your diet.
Higher-Fiber Swaps
If you eat rice regularly and struggle with constipation, consider these changes:
- Brown rice is the simplest swap, offering roughly four times the fiber of white rice with a similar taste and texture.
- Black and red rice varieties retain their bran and often deliver even more fiber than standard brown rice, along with additional antioxidants.
- Quinoa, barley, and bulgur are whole grains that provide 5 to 8 grams of fiber per cooked cup, significantly outperforming white rice.
- Mixing grains works well if you prefer the taste of white rice. Cooking it with lentils, barley, or wild rice adds fiber without completely changing the dish.
Whenever you increase your fiber intake, drinking more water matters. Fiber absorbs water to do its job, and adding fiber without adequate fluids can actually make constipation worse in the short term. Increasing fiber gradually over a week or two also helps avoid bloating and gas as your gut bacteria adjust.
The Bottom Line on Rice and Constipation
White rice doesn’t automatically cause constipation in everyone. Small servings alongside a varied, fiber-rich diet are unlikely to cause problems. The risk comes when white rice dominates your meals and displaces the fiber your colon depends on. Cooling and reheating leftover rice, choosing brown or whole-grain varieties, and pairing rice with high-fiber sides are all practical ways to enjoy rice without paying for it in the bathroom.