White rice is one of the easiest foods to digest. Plain cooked white rice spends only 30 to 60 minutes in your stomach, then another 40 to 120 minutes moving through your small intestine. That’s fast compared to most solid foods, and it’s why rice is a go-to recommendation when your gut needs a break.
Brown rice, on the other hand, digests noticeably slower. The difference comes down to structure: what’s been removed from the grain, what’s left behind, and how you cook it all change how quickly your body can break rice down.
Why White Rice Breaks Down So Fast
A grain of white rice is mostly starch, with the fibrous outer layers (the bran and germ) stripped away during milling. That matters because fiber slows digestion, and without it, your digestive enzymes have direct access to the starch inside.
Cooking accelerates things further. Raw rice starch is packed into tight crystalline structures that resist breakdown. When you boil or steam rice, heat and water destroy those structures in a process called gelatinization. Once fully cooked, the starch is wide open for your enzymes to work on. This is why cooked white rice has a high glycemic index: your body converts it to glucose quickly.
The type of starch in rice also plays a role. Rice starch is mostly amylopectin, a large, highly branched molecule. Larger amylopectin molecules have more “entry points” where digestive enzymes can latch on, which speeds up the rate of breakdown. Compared to foods rich in the other type of starch (amylose, which is a long, straight chain), rice gives your digestive system less work to do.
Brown Rice Is Harder on Your Gut
Brown rice keeps its bran and germ layers intact, which means more fiber, more texture, and a slower digestive process. The fiber isn’t just filler. It physically shields the starch granules from your enzymes, forcing your gut to work harder and longer to extract the same energy. For most healthy people, that extra fiber is a benefit: it feeds gut bacteria, slows blood sugar spikes, and supports regular bowel movements.
But if you’re dealing with bloating, cramping, diarrhea, or a sensitive stomach, brown rice can make things worse. The bran layer also contains phytic acid, a compound that binds to minerals like zinc and iron and reduces how much your body absorbs. Soaking brown rice before cooking helps. Soaking at warm temperatures for 24 hours removes roughly 42 to 59% of the phytic acid, though a simple room-temperature soak for the same time removes less than 20%. Fermentation is the most effective method, stripping away 56 to 96% of phytic acid, but it’s not something most home cooks do routinely.
Rice for an Upset Stomach
Rice has long been part of the BRAT diet (bananas, rice, applesauce, toast), a classic home remedy for nausea, food poisoning, traveler’s diarrhea, and stomach flu. All four foods are soft, bland, and low in fiber, which makes them gentle on an irritated digestive tract. Plain white rice fits this role well because it doesn’t stimulate much acid production or gut motility.
That said, the medical view on BRAT has shifted. The American Academy of Pediatrics no longer recommends it for children with diarrhea because it’s too nutritionally restrictive, and sticking with it for more than 24 hours may actually slow recovery. For adults, eating BRAT foods for a day or two at the worst of an illness is fine, but you should move back to a more varied diet as soon as you can tolerate it. Rice can absolutely be part of your recovery, just not the only thing on your plate for days at a time.
Rice and Digestive Conditions Like IBS
If you have irritable bowel syndrome, rice is one of the safest starches you can eat. It’s naturally low in FODMAPs, the group of fermentable carbohydrates that trigger symptoms in many people with IBS. Monash University, the leading research group behind the low-FODMAP diet, lists rice and plain rice cakes as safe options. Unlike wheat, rye, or certain legumes, rice doesn’t contain the sugars that pull extra water into the gut or produce excess gas during fermentation.
This makes white rice a reliable base when you’re trying to identify which foods bother you. It’s unlikely to be the culprit, so it works well as a “safe food” during an elimination diet.
How Cooling Changes Digestibility
Here’s something counterintuitive: rice that’s been cooked and then cooled becomes slightly harder to digest, and that can be a good thing. When cooked rice cools, some of the gelatinized starch rearranges itself back into tighter structures, forming what’s called resistant starch. Your small intestine can’t break down resistant starch, so it passes to your colon where gut bacteria ferment it, producing compounds that support colon health.
The numbers are modest but real. Freshly cooked white rice contains about 0.64 grams of resistant starch per 100 grams. Rice cooled for 10 hours at room temperature nearly doubles that to 1.30 grams. Rice cooled in the fridge for 24 hours and then reheated reaches 1.65 grams. Reheating doesn’t reverse the effect entirely, so leftover rice and dishes like fried rice or cold rice salads deliver more resistant starch than a freshly made pot.
If easy digestion is your priority (say, during illness or a flare-up), eat rice freshly cooked. If you want to feed your gut bacteria and blunt the blood sugar spike, cooled or reheated rice gives you a small edge.
White Rice vs. Brown Rice: Picking the Right One
- For easy digestion: White rice wins. Less fiber, faster enzyme access, gentler on a sensitive stomach.
- For blood sugar control: Brown rice is better. The fiber slows glucose absorption.
- For nutrient density: Brown rice has more B vitamins, magnesium, and phosphorus, though phytic acid reduces mineral absorption unless you soak or ferment it first.
- For lower arsenic exposure: White rice contains about 40% less inorganic arsenic than brown rice of the same variety (roughly 92 parts per billion vs. 154 ppb), because arsenic concentrates in the bran and germ layers that are removed during milling.
Neither choice is universally better. Your gut health, your blood sugar goals, and how you feel after eating each type should guide the decision. For most people without digestive issues, alternating between the two is perfectly reasonable. For anyone recovering from illness or managing a condition like IBS, white rice is the safer daily staple.