Does Skim Milk Count Towards Daily Water Intake? The Surprising Hydration Facts

November 3, 2025 •

4 min read

Did you know that studies show some beverages are more hydrating than plain water for longer periods? This scientific finding gives new context to the question: does skim milk count towards daily water intake, confirming it's an excellent source of fluid and more, especially after intense exercise.

Quick Summary

Skim milk is a valid source of daily fluid intake, providing hydration through its high water content along with electrolytes, protein, and carbohydrates. Research indicates that these components help the body retain fluids more effectively than plain water in certain situations, such as post-exercise, but plain water should remain the primary beverage for most daily hydration needs.

Key Points

Skim Milk is Hydrating: Skim milk is approximately 90% water and actively contributes to your daily fluid intake, much like other beverages.
Superior Fluid Retention: The electrolytes, protein, and carbohydrates in skim milk help the body retain fluid more effectively and for longer periods compared to plain water.
Scientifically Backed Hydration: The Beverage Hydration Index (BHI) confirms that skim milk has a higher hydrating capacity than water, showing less fluid loss in the hours after consumption.
Best for Post-Workout Recovery: With its perfect blend of water, electrolytes, protein, and carbs, skim milk is an ideal beverage for rehydration and muscle repair after intense exercise.
Water is Still Key for Everyday Intake: While milk offers enhanced hydration, plain water remains the most practical and calorie-free choice for routine, everyday hydration.
Nutrient-Dense Hydration: Choosing skim milk provides the added benefits of calcium, protein, and vitamin D along with hydration, unlike plain water which is purely fluid.
Calorie Consideration: Be mindful that unlike water, milk contains calories and sugars, so it should be integrated thoughtfully into your overall dietary plan, not as a full replacement for water.

Milk's Composition: More Than Just Water

For a long time, the advice for staying hydrated focused solely on drinking plain water. While water is undoubtedly essential and calorie-free, modern nutrition science paints a more complex picture of what truly makes a beverage effective at hydrating the body. It turns out that other compounds within a drink can significantly influence how well and for how long the body retains fluid.

At its core, milk is approximately 90% water. But what sets it apart is the powerful blend of additional nutrients it contains, even in its fat-free form. Skim milk is a source of electrolytes, such as sodium and potassium, along with protein and natural sugars (lactose). This combination is crucial to understanding its hydrating properties. When you consume a liquid, its composition affects the body's digestive and fluid-absorption processes. The electrolytes help regulate fluid balance, while the macronutrients (protein and carbohydrates) slow down gastric emptying, resulting in a more gradual and prolonged absorption of fluid into the bloodstream. This contrasts with plain water, which is absorbed more quickly and can lead to faster urination and fluid loss.

The Science Behind the Beverage Hydration Index (BHI)

In 2016, researchers at Loughborough University developed the Beverage Hydration Index (BHI) to scientifically compare how different beverages affect hydration. The study measured urine output over a four-hour period after subjects consumed various fluids, with still water serving as the baseline (BHI of 1.0). The results were surprising to many: skim milk actually performed better than water, registering a significantly higher BHI (1.58). This indicates that the body retained more of the fluid from skim milk than from an equal volume of plain water over the study period. Other beverages, like orange juice and oral rehydration solutions, also scored high, while drinks like cola and coffee were on par with water.

The reason for milk's high BHI lies in its nutritional content. The combination of water, electrolytes, protein, and carbs creates a solution that is better retained by the body. The electrolytes help balance fluid levels, while the protein and carbohydrates slow digestion, allowing for a more sustained release of fluids into the system rather than a rapid flush that triggers urination.

When is Skim Milk the Best Hydrating Choice?

While skim milk is demonstrably effective at rehydrating, it's not meant to replace plain water entirely. Water is calorie-free and remains the gold standard for routine, everyday hydration. However, there are specific scenarios where skim milk's unique nutrient profile makes it a superior option.

Post-Intense Exercise: After a strenuous workout, your body has lost significant fluids and electrolytes through sweat and needs to replenish glycogen stores. Skim milk offers the ideal trifecta for recovery: water for rehydration, protein for muscle repair, and carbohydrates to restore energy. Research supports that milk is more effective than water or many sports drinks for post-exercise recovery.
Mild Dehydration: For minor cases of dehydration, such as when you feel parched after being out in the heat, the electrolytes in skim milk can help your body retain fluids more effectively and get you back to a balanced state.
Nutrient-Enhanced Hydration: For individuals who find plain water unappealing or are trying to increase their intake of key nutrients like calcium and Vitamin D, incorporating a glass of skim milk is a great strategy. It offers hydration alongside valuable nutritional benefits.

Foods and Beverages that Contribute to Daily Water Intake

Beyond water and milk, many other sources can help you meet your daily fluid needs. The total water intake includes liquids from beverages and water-rich foods.

Fruits and Vegetables: Watermelon, strawberries, cantaloupe, peaches, oranges, cucumbers, lettuce, and celery are all excellent sources of water.
Tea and Coffee: Despite their caffeine content, moderate consumption of tea and coffee contributes positively to hydration due to their high water content.
Soups and Broths: These are liquids that are naturally high in water and also provide sodium and other electrolytes, similar to milk.
Juices and Smoothies: Fruit juices and smoothies contain water, but their sugar and calorie content should be monitored.
Oral Rehydration Solutions: Products designed to treat dehydration contain a specific balance of water, sugar, and electrolytes for maximum fluid retention.

Skim Milk vs. Water for Hydration: A Comparison


Feature	Skim Milk	Water
Water Content	~90%	100%
Calorie Content	Higher (~83 kcal/cup)	Zero
Nutrients	Protein, Calcium, Vitamins, Electrolytes	None (can contain minerals depending on source)
Hydration Efficiency (BHI)	Higher than water, retains fluid longer	Baseline, absorbs quickly, faster fluid loss
Taste/Flavor	Mild, creamy flavor	Neutral
Ideal Use	Post-exercise, specific nutrient needs	Everyday, general hydration, calorie-free fluid
Effect on Appetite	Higher satiety due to protein and fat	Does not significantly affect satiety

Conclusion: Finding the Right Balance for Your Diet

Yes, skim milk absolutely counts towards your daily water intake, and research suggests it's a remarkably effective hydrating beverage due to its combination of water, electrolytes, and macronutrients. These components allow the body to retain its fluids for a longer period than with plain water, which can be especially beneficial in certain scenarios like post-workout recovery. However, this does not mean you should replace all your water with milk. For daily, routine hydration, water remains the best, calorie-free option. The key is to see skim milk as a nutritious and efficient tool in your hydration toolkit, not as a complete substitute for water. Incorporating a variety of fluids and water-rich foods, including a glass of skim milk, is the best approach for a balanced diet and optimal hydration.

For more information on overall healthy hydration, visit the NHS website.

Frequently Asked Questions

Studies using the Beverage Hydration Index (BHI) show that skim milk is actually more hydrating than water over a four-hour period. This is because its electrolytes, protein, and carbs help the body absorb and retain fluids for longer.

No. While skim milk is hydrating, it contains calories and natural sugars. Replacing all your water with milk would significantly increase your calorie intake, which may not align with your dietary goals. Water should be your primary fluid source.

The protein and carbohydrates in milk slow down its passage through the stomach. This slower absorption rate, combined with the presence of electrolytes like sodium and potassium, helps your body hold onto the fluid for a longer duration.

Skim milk contains a higher percentage of water than whole milk. While both are very hydrating, some research suggests skim milk may be slightly more effective for fluid retention due to its lower fat content.

Yes, skim milk is an excellent recovery drink. It provides water, carbohydrates to replenish energy stores, protein to repair muscles, and electrolytes to replace those lost through sweat.

Yes, almost all beverages containing water, including coffee and tea (in moderation), contribute to your daily fluid intake. It's a common myth that caffeinated drinks dehydrate you, but the hydrating effect from their water content outweighs the mild diuretic effect of caffeine.

Signs of dehydration can include thirst, fatigue, dizziness, dry mouth, and dark-colored urine. Monitoring your urine color is a simple way to gauge your hydration status; pale yellow or clear urine is a good sign of proper hydration.