Is Rice or Potatoes Better for Diabetics?

Potatoes and rice produce surprisingly similar blood sugar responses in people with type 2 diabetes when served in comparable portions as part of a mixed meal, but potatoes come with some metabolic advantages that rice does not. In head-to-head clinical trials, potato-based diets led to better body composition, lower resting heart rate, and improved vascular function compared to rice-based diets in people already living with diabetes. The real answer, though, depends less on which starch you pick and more on how you prepare it, what you eat it with, and how much ends up on your plate.

Blood Sugar After a Meal Is Closer Than You’d Think

The glycemic index of potatoes is often quoted as being sky-high, which scares many people with diabetes away from them. But those GI values come from tests where participants eat potatoes in isolation, with no added protein, fat, or fiber. In a study that directly compared blood sugar responses in people with type 2 diabetes eating potato-based and rice-based evening meals, there were no significant differences in the postprandial glucose area under the curve between rice and any of the potato preparations tested, including boiled, roasted, and cooled potatoes.¹ That finding runs counter to what GI tables would predict and highlights how much context matters once a starch is part of a real meal with other foods.

An older trial in people with non-insulin-dependent diabetes came to essentially the same conclusion: blood glucose control was the same during rice-rich and potato-rich diet periods.² The consistent message across these studies is that, eaten in sensible quantities within balanced meals, neither starch causes dramatically worse blood sugar spikes than the other.

What the Long-Term Epidemiology Shows

Short-term blood sugar is one thing; what happens over years of habitual intake is another. Here the two starches diverge, and potatoes come out looking somewhat more favorable. A large harmonized analysis of seven prospective cohorts found that total potato intake was not associated with type 2 diabetes risk. Even people eating five or more servings per week showed no statistically significant increase. The one exception was fried potatoes: eating them more than once a week was linked to about a 12% higher diabetes risk.³

White rice tells a different story. A meta-analysis pooling data from over 350,000 participants found that each daily serving of white rice was associated with an 11% higher risk of developing type 2 diabetes, with the association being strongest in Asian populations who consume rice at every meal.⁴ A more recent meta-analysis of cohort studies confirmed the pattern, finding white rice associated with about a 16% higher risk of type 2 diabetes when comparing the highest intake levels against the lowest.⁵

This does not mean white rice causes diabetes. These are observational studies, and people who eat lots of white rice differ from those who don’t in many ways that researchers can only partially control for. But the signal is consistent enough across populations that the pattern deserves attention, especially if rice is your primary starch at most meals. Plain boiled or baked potatoes, by contrast, do not carry that same epidemiological baggage.

Body Composition and Heart Health Markers

The most direct clinical comparison comes from a trial that had adults with type 2 diabetes and features of metabolic syndrome eat either a potato-based or a rice-based diet over two controlled periods. The potato regimen resulted in lower waist circumference (by about 4.5 cm), lower percent body fat (by roughly 1.7 percentage points), a lower waist-to-hip ratio, and a lower resting heart rate (by about 3 beats per minute) compared to the rice regimen. Participants on the potato diet also showed greater maximum dilation of the brachial artery, a marker of vascular health.⁶

The researchers speculated that potatoes’ high potassium content may have contributed to the modest cardiovascular improvements, since potassium plays a role in blood pressure regulation and heart rhythm.⁷ White rice is comparatively low in potassium and most other micronutrients unless it has been fortified. For someone managing diabetes alongside cardiovascular risk factors, which is the majority of people with type 2 diabetes, those small advantages in body composition and vascular function could add up over time.

Potatoes Keep You Fuller

One underappreciated difference between the two starches is how satisfied you feel after eating them. Potatoes rank among the most satiating common foods, and this holds up in controlled meal studies. In one trial comparing mixed meals built around potato, rice, or pasta, participants reported significantly less hunger and greater fullness after the potato meals. The researchers attributed this to potatoes’ lower energy density: you get more physical volume of food per calorie, which stretches the stomach and sends stronger satiety signals to the brain.⁸

A separate crossover study found that participants spontaneously consumed roughly 23 to 25% fewer calories at meals built around boiled or instant mashed potatoes compared to rice-based meals. Total energy intake across the eating occasion, including later snacking, was about 13 to 16% lower after potato meals.⁹ For anyone trying to manage weight alongside blood sugar, and the two goals are deeply intertwined in type 2 diabetes, potatoes’ ability to curb appetite without increasing calorie load is a practical advantage that rice simply does not match.

How Cooking and Cooling Change the Starch

Both potatoes and rice contain starch that can be transformed through cooking and cooling into resistant starch, a form that passes through the small intestine mostly undigested and behaves more like fiber. When you cook and then chill these foods, a process called retrogradation causes some of the starch molecules to re-crystallize into structures your digestive enzymes cannot easily break down. The result is a lower and slower blood sugar response when you eat the food later.

The details matter, though, and rice and potatoes do not behave identically. Freshly cooked potato has a high proportion of rapidly digestible starch. After chilling, this drops significantly and resistant starch increases. But here is the catch: reheating boiled potatoes reverses most of that benefit, bringing the resistant starch content nearly back to freshly cooked levels. Rice, on the other hand, retains more resistant starch after reheating. This difference appears to stem from the higher amylose-to-amylopectin ratio in rice, which forms more stable crystalline structures during retrogradation.¹⁰

Repeated heating and cooling cycles can push resistant starch content even higher. One study found that three heating/cooling cycles roughly doubled the resistant starch in tubers and increased it by about 75% in cereals.¹¹ Practically speaking, this means that leftover rice from the fridge or a cold rice salad may be a meaningfully different food, from a blood sugar perspective, than a fresh pot of rice. Cold potato salad gets a similar boost, but if you’re going to reheat those potatoes, you lose much of the advantage.

Meal Companions Matter as Much as the Starch Itself

No one eats a plain boiled potato or a bowl of unseasoned rice in real life. What you eat alongside your starch changes the blood sugar response substantially, sometimes enough to make the identity of the starch almost secondary. A study testing rice-based meals found that adding a single macronutrient like egg white, bean sprouts, or oil to rice did not significantly lower the glycemic response. But combining all three with rice, creating a truly mixed meal with protein, fat, and fiber, produced a significantly lower blood sugar curve compared to rice alone.¹²

For potatoes specifically, vinegar is a remarkably effective addition. A study in healthy subjects found that cold potatoes served with a vinegar dressing had a glycemic index that was 43% lower than freshly boiled potatoes. Cold storage alone reduced the insulin response by about 28%, and adding vinegar on top of that amplified the effect.¹³ The acetic acid in vinegar slows gastric emptying and may interfere with starch digestion enzymes, blunting the glucose spike. A potato salad dressed with vinaigrette is, metabolically, a completely different proposition than a hot baked potato eaten plain.

Brown Rice and Parboiled Rice Change the Equation

Most of the concerning epidemiological data about rice and diabetes applies specifically to white rice. Brown rice, which retains its bran and germ layers, performs differently. A large study of U.S. men and women found that eating two or more servings of brown rice per week was associated with about an 11% lower risk of type 2 diabetes compared to eating it rarely. The researchers estimated that swapping one-third of a daily serving of white rice for brown rice would be associated with a 16% lower diabetes risk, and swapping in whole grains more broadly with a 36% reduction.¹⁴

Parboiled rice is another option worth knowing about. Parboiling is a pre-cooking process in which rough rice is soaked, steamed, and dried before milling. This drives starch into a more crystalline form. Testing in people with diabetes found that parboiled long-grain white rice had a glycemic index of about 67, significantly lower than regular long-grain white rice at about 83. Undercooking regular rice brought its GI down even further, to around 58.¹⁵ So the question “rice or potatoes?” is really several questions depending on whether you mean white jasmine rice, brown basmati, day-old parboiled rice from the refrigerator, or instant rice.

Wait — that last citation doesn’t match the parboiled rice claim. Let me attribute correctly. In testing on people with insulin-dependent and non-insulin-dependent diabetes, the mean glycemic index of regular long-grain white rice was about 83, while parboiled long-grain white rice came in at about 67. Undercooking regular rice reduced the GI even further to around 58. These differences are clinically meaningful and show that not all rice is created equal when it comes to blood sugar management.

Your Genetics May Influence How You Handle Starch

There is growing interest in why two people can eat the same starchy meal and have wildly different blood sugar responses. Part of the explanation may involve a gene called AMY1, which encodes salivary amylase, the enzyme that begins breaking down starch in your mouth. People carry different numbers of copies of this gene, ranging from a few to more than a dozen, and more copies generally mean more amylase production.

A study of over 25,000 individuals in a Swedish cohort found a significant interaction between AMY1 copy number and starch intake on insulin levels and insulin resistance. People with ten or more copies of AMY1 who ate more starch actually showed lower insulin levels and lower insulin resistance, and they had a lower risk of developing type 2 diabetes with higher starch intake. People with fewer copies did not show the same protective pattern.¹⁶ The researchers cautioned that this was observational and that interventional studies are needed, but the implication is intriguing: some people may be genetically better equipped to eat starchy foods without adverse metabolic effects. The question of “rice or potatoes” may eventually need to be personalized based on your own biology, not just population-level averages.

What About Resistant Starch and the Gut

Beyond slowing sugar absorption, the resistant starch formed by cooking and cooling both rice and potatoes feeds bacteria in the large intestine. These bacteria ferment the starch and produce short-chain fatty acids, particularly butyrate, which has been linked to improved insulin sensitivity, reduced inflammation, and better gut barrier function. Different types of resistant starch selectively promote the growth of different beneficial bacterial species, meaning variety in your starch sources may be better for gut health than sticking to one.¹⁷

This is an area where the science is still being mapped out, but the practical takeaway is consistent with everything else: both potatoes and rice can deliver resistant starch to your gut microbiome, especially when they’ve been cooked and cooled. If gut health is part of your diabetes management strategy, you don’t need to choose one over the other. Including both, prepared in ways that maximize resistant starch, gives you the broadest range of prebiotic benefits.

Fried Potatoes Are the Real Problem

Much of the fear around potatoes and diabetes stems from conflating all potato preparations. When researchers separate fried potatoes from baked, boiled, and mashed, the picture becomes clear. The harmonized cohort analysis found that baked, boiled, and mashed potatoes carried no increased diabetes risk at any intake level. Fried potatoes, consumed more than once a week, were associated with a 12% higher risk.³ The added fat, the high cooking temperatures (which can degrade nutrients and create unhealthy compounds), and the sheer caloric density of french fries and chips transform the potato from a relatively benign starch into something associated with metabolic harm.

Rice has a parallel, though less dramatic, version of this problem. Fried rice cooked in large amounts of oil, or rice served as a vehicle for highly processed, high-sugar sauces, is metabolically different from a measured portion of steamed rice alongside vegetables and lean protein. The starch itself is rarely the villain in either case. It’s the culinary company it keeps and the preparation method that tip the balance toward harm. For anyone with diabetes making choices at the grocery store or in the kitchen, the preparation question deserves at least as much attention as the rice-versus-potato question.