Does White Rice Hydrate You? A Closer Look at the Facts

November 28, 2025 •

4 min read

Approximately 70% of cooked rice is water, suggesting it contributes to daily fluid intake. However, the notion that simply eating white rice is a reliable hydration strategy is more complex. Understanding how the body processes carbohydrates in rice is key to knowing if and how it supports your hydration.

Quick Summary

Cooked white rice provides fluid, but factors like carbohydrate load and processing methods influence its overall hydrating effect. The starchy cooking liquid, or rice water, is often more effective for rehydration, particularly in cases of illness.

Key Points

Cooked rice is mostly water: Approximately 70% of cooked white rice is water, meaning it does contribute to your daily fluid intake.
Carbohydrate load impacts hydration: The high carbohydrate content can cause water to be used for converting glucose to glycogen, which can temporarily reduce available fluids.
Rice water is more effective for rehydration: The starchy liquid from boiling rice, especially with added salt, is a better source for rehydrating, particularly for mild digestive issues.
Not a replacement for water: Cooked white rice should not be considered a primary or reliable source of hydration; plain water and high-water-content foods are more efficient.
Balanced diet is key: The best approach is to consume white rice in moderation as part of a balanced meal with other hydrating foods like fruits and vegetables.
Watch for water retention: For some, the high carbohydrate content of white rice can contribute to water retention, causing bloating.

The Water Content of Cooked White Rice

When you cook white rice, it absorbs a significant amount of water. As a result, a serving of cooked white rice contains roughly 70% water by weight. This makes it a source of food-based fluid, contributing to your overall hydration, similar to other water-rich foods. While eating cooked rice can certainly add fluid to your system, it is not a primary or standalone solution for rehydration, especially during significant fluid loss.

The Role of Carbohydrates and Glycogen

White rice is primarily a source of carbohydrates, which your body converts to glucose for energy. This glucose can be stored in the muscles and liver as glycogen. The process of storing glycogen requires water; specifically, about 4 grams of water are needed for every 1 gram of glycogen stored. If your glycogen stores are depleted, consuming a large amount of carbohydrates from white rice could cause water to shift to replenish these stores. Some studies suggest that in this specific state, the water needed for glycogen storage could potentially create a temporary net dehydrating effect, although the water absorbed during cooking would still contribute some fluid. In contrast, consuming refined carbohydrates can also lead to water retention and bloating in some individuals.

The Special Case of Rice Water

Unlike solid cooked rice, the leftover starchy liquid from boiling rice, known as rice water, has been traditionally used as a rehydration fluid in some cultures. Historically, particularly in cases of diarrhea, rice water was given to children to help replenish lost fluids.

Benefits of Rice Water for Rehydration

Replenishes Lost Fluids: Drinking rice water directly helps restore fluids lost due to heat, vomiting, or diarrhea.
Contains Electrolytes: Though not a balanced oral rehydration solution (ORS), it can contain electrolytes like potassium and magnesium, especially if prepared with a pinch of salt.
Soothes Digestion: The starchy nature of rice water can have a soothing effect on the gut, which can be beneficial during digestive upset.
Hypo-osmotic Properties: Some research suggests that the low osmolality of rice water can lead to increased water absorption in the intestines.

Comparison: Cooked Rice vs. Rice Water for Hydration


Feature	Cooked White Rice	Rice Water (with Salt)	Plain Water
Primary Function	Energy source, moderate fluid contribution	Fluid and mild electrolyte replacement	Direct fluid replacement
Water Content	~70% water by weight	>95% water	100% water
Carbohydrate Load	High, impacting glycogen storage	Low to moderate	None
Electrolyte Source	Minimal	Provides some electrolytes (K, Mg, Na)	None
Digestive Impact	Provides resistant starch, can cause bloating in excess	Soothes upset stomachs	Neutral
Best For	General energy and moderate fluid	Rehydration during mild illness	Daily, optimal hydration

Better Food Choices for Hydration

For optimal hydration, particularly for preventing dehydration during exercise or hot weather, foods with a high water content and a good balance of electrolytes are recommended. These include:

Fruits: Watermelon, strawberries, cantaloupe, peaches, and oranges.
Vegetables: Cucumbers, lettuce, celery, and spinach.
Dairy: Skim milk and yogurt can be effective due to their water, protein, and electrolyte content.
Soups and Broths: These contain both fluid and electrolytes, making them excellent for rehydration.

Incorporating White Rice into a Balanced Hydration Strategy

Pair with High-Water Foods: Serve white rice alongside water-rich vegetables like cucumber salad or a stir-fry with broccoli and bell peppers. This increases the overall hydrating potential of your meal.
Control Portion Sizes: To avoid the potential for excessive water retention linked to high carbohydrate intake, consume white rice in moderation as part of a balanced meal.
Stay Hydrated Separately: Do not rely on white rice alone to meet your fluid needs. Continue to drink plenty of plain water throughout the day.
Consider Whole Grains: While white rice provides some benefits, whole grains like brown rice may help flush out excess water and promote digestion due to higher fiber content.

Conclusion

While cooked white rice does contain water and contributes to your daily fluid intake, it is not a highly effective tool for active rehydration. Its carbohydrate content can cause water to be utilized for glycogen storage, and excessive intake can lead to water retention. The traditional use of rice water is a more direct approach to rehydration, especially when enhanced with salt for electrolytes, and can be particularly useful during illness. However, for general, daily hydration, water-rich fruits, vegetables, and plain water are superior. For a truly effective electrolyte solution, a commercially prepared or properly formulated homemade ORS remains the standard of care for severe dehydration.

For more detailed information on rice-based oral rehydration solutions, refer to the systematic reviews cited on the National Institutes of Health website.

Frequently Asked Questions

No, you should not rely on white rice as a substitute for drinking water. While cooked rice contains a significant amount of water, it is not a direct replacement for the fluid your body needs from beverages. Plain water is the most efficient and direct way to stay hydrated.

Historically, rice water has been used as a folk remedy for diarrhea and mild dehydration. Some studies suggest it can be mildly effective due to its water, starch, and electrolyte content when salt is added, but it is not a substitute for standard oral rehydration solutions recommended by health organizations.

For some people, especially when consumed in large quantities, the refined carbohydrates in white rice can cause water retention, which may lead to a bloated feeling. Keeping portion sizes in check and pairing it with fiber-rich foods can help mitigate this effect.

Cooked white rice contains very few minerals, so its impact on electrolyte balance is minimal. Rice water, especially with added salt, is more effective at providing a minor boost of electrolytes like sodium, potassium, and magnesium to help maintain balance during fluid loss.

Both cooked white and brown rice contain a high percentage of water. However, brown rice retains more of its nutrients and fiber, which helps promote healthy digestion. Both are food-based sources of water, but neither is an optimal hydration strategy on its own.

Water-rich foods like cucumbers, watermelon, berries, leafy greens, and broths are much better for rehydration than white rice. These foods not only provide fluids but also deliver electrolytes and vitamins crucial for proper hydration.

To increase the hydrating effect of a white rice meal, pair it with plenty of vegetables that have a high water content. You can also have it with a broth-based soup or a glass of water to ensure you are getting adequate fluids.