Does Rice Have a Diuretic Effect?

October 24, 2025 •

4 min read

While some online sources suggest that rice acts as a diuretic, modern scientific consensus indicates that the opposite is true. Rice, particularly when cooked, promotes fluid retention in the body, primarily through its carbohydrate content, which binds to water molecules.

Quick Summary

The diuretic effect of rice is largely a myth; cooked rice actually promotes fluid retention due to its carbohydrates binding with water. This guide explores the different types of rice and their impact on fluid balance and electrolyte levels.

Key Points

Rice is not a diuretic: Contrary to some myths, cooked rice promotes fluid retention, not excretion.
Carbohydrates and water retention: The high carbohydrate content in rice is stored as glycogen, which binds water, causing the body to retain fluids.
White vs. brown rice: Brown rice contains higher levels of potassium and phosphorus than white rice, which is a consideration for those with kidney disease.
Rice water for rehydration: Rice water can contain electrolytes like potassium, and when combined with salt, can be used to aid in rehydration, not to cause diuresis.
The 'rice diet' effect: The diuretic effect associated with historical 'rice diets' was due to severe sodium restriction, not the rice itself.
Electrolyte content: While rice has some electrolytes, it is not a primary source compared to other foods and is not considered a diuretic.

Understanding Diuretics and Rice

Diuretics are substances that promote increased urination, helping the body get rid of excess water and sodium. While some foods and herbs are known to have mild diuretic properties, rice is not among them. The primary role of cooked rice in the body's fluid balance is actually to help retain water, a mechanism essential for energy storage and overall hydration. For every gram of glycogen (stored carbohydrate) in the body, approximately three grams of water are also stored. Since rice is a carbohydrate-rich food, eating it leads to increased glycogen storage and, consequently, water retention.

The Role of Carbohydrates in Fluid Balance

The intricate relationship between carbohydrates and hydration is crucial for athletic performance and general health. When you eat rice, your body converts the carbohydrates into glucose, which is then stored as glycogen in your muscles and liver. This process is what causes the body to hold onto water. For this reason, athletes often 'carb-load' with foods like rice before a major event to increase their energy and hydration levels. This mechanism highlights why the idea of rice being a diuretic is unfounded.

Comparing White and Brown Rice

The type of rice you consume can affect its impact on your body, though not in a way that makes it a diuretic. The main difference lies in the mineral content, particularly potassium and phosphorus, which are important for those with kidney-related dietary restrictions.


Feature	White Rice	Brown Rice
Processing	Milled and polished, removing the outer husk and bran layer.	Only the outer husk is removed, keeping the nutrient-rich bran layer.
Potassium Content	Lower in potassium.	Higher in potassium.
Phosphorus Content	Lower in phosphorus.	Higher in phosphorus.
Fiber Content	Lower in fiber.	Significantly higher in fiber.
Glycemic Index	Higher glycemic index due to processing.	Lower glycemic index.
Fluid Impact	Primarily promotes fluid retention through carbohydrate-glycogen conversion, similar to brown rice.	Promotes fluid retention through carbohydrate-glycogen conversion, with slightly higher electrolytes.

For individuals with compromised kidney function, the higher potassium and phosphorus levels in brown rice can be a concern, making white rice the preferred option as advised by healthcare professionals. However, neither variety possesses true diuretic properties. For most healthy individuals, both types of rice are a safe and energy-rich part of a balanced diet.

The Case of Rice Water

Interestingly, while cooked rice is not a diuretic, the liquid byproduct of boiling it, known as rice water, is sometimes used as a rehydration remedy. This is because rice water contains electrolytes like potassium and magnesium, which can help replenish lost fluids and maintain fluid balance, similar to a mild oral rehydration solution. However, this effect is for rehydration, not diuresis. Furthermore, some studies indicate rice water may contain trace amounts of arsenic, depending on the rice source, so it should be consumed in moderation.

The Importance of Electrolytes

Fluid balance is a complex physiological process that depends on a delicate balance of water and electrolytes, such as sodium and potassium. While rice does contain some electrolytes, it is a relatively minor source compared to foods like fruits and vegetables. The misconception about rice being a diuretic might stem from a misunderstanding of how the body regulates fluid through different dietary components. Carbohydrates play a role in water storage, while other compounds might influence urination more directly.

Conclusion: No Diuretic Effect, but a Role in Hydration

In summary, the notion that rice has a diuretic effect is a common myth. The scientific evidence indicates that rice, a carbohydrate-dense food, primarily contributes to fluid retention through the process of storing glycogen. While some rice-based products, like rice water with added salts, can be used for rehydration, this is different from a diuretic action that promotes water excretion. The varying mineral content between white and brown rice can influence dietary choices, especially for those with kidney conditions, but neither type is a true diuretic. Always consult a healthcare professional for dietary advice, particularly concerning fluid balance and underlying health conditions.

What About the 'Rice Diet'?

Historically, the 'rice diet' was a severely restricted, low-sodium diet that used rice as a base and was primarily used to treat hypertension and kidney disease. Any diuretic effect observed on this diet would have been due to the extremely low sodium intake rather than the rice itself. When sodium intake is drastically cut, the kidneys excrete more water to help balance electrolyte concentrations, creating a diuretic-like response. The rice merely served as a low-sodium, high-carbohydrate food source for this regimen, not as the diuretic agent itself.

Frequently Asked Questions

No, rice is not a natural diuretic. Instead, its high carbohydrate content causes the body to retain water by storing it alongside glycogen in the muscles and liver.

The misconception may come from older traditional medicine beliefs or from the effects of the historical 'rice diet,' which was severely low in sodium. Any diuretic effect was caused by the sodium restriction, not the rice.

No, brown rice does not have a diuretic effect. Like white rice, its carbohydrates cause fluid retention. Brown rice does, however, contain higher levels of potassium and phosphorus, which is a key nutritional difference.

Rice water, the liquid left after boiling rice, is not a diuretic. It contains electrolytes and is sometimes used as a mild rehydration remedy, but it does not promote increased urination.

Yes, a diet severely restricted in sodium, like the historical 'rice diet,' can cause a diuretic effect. This is because the body increases water and salt excretion to balance its internal electrolyte levels due to the lack of dietary sodium.

For individuals with compromised kidney function who need to limit potassium and phosphorus intake, white rice is often a better choice than brown rice due to its lower mineral content.

For athletes, rice is a valuable source of carbohydrates used for 'carb-loading' before endurance events. The storage of these carbohydrates as glycogen also helps retain water, which is important for maintaining hydration during physical exertion.