What Are the Best Drinks for Hydration?
Not all drinks hydrate equally. The Beverage Hydration Index ranks common drinks by how well your body retains their fluid.
While plain water is the gold standard for hydration, research from Loughborough University published in the American Journal of Clinical Nutrition introduced the Beverage Hydration Index (BHI) in 2016, ranking drinks by how effectively the body retains their fluid over four hours. The results surprised many: milk, oral rehydration solutions, and even orange juice outperformed plain water in fluid retention. The key factors are electrolyte content (which slows fluid excretion), calorie density (which slows gastric emptying), and macronutrient composition. Understanding these rankings can help you make smarter hydration choices throughout the day.
Beverage Hydration Index Rankings
| Rank | Beverage | Hydration Score | Key Factor |
|---|---|---|---|
| 1 | Oral Rehydration Solution | 1.54 Optimal electrolyte balance for absorption | |
| 2 | Skim Milk | 1.58 Lactose, protein, and sodium slow excretion | |
| 3 | Whole Milk | 1.50 Fat content slows gastric emptying | |
| 4 | Orange Juice | 1.10 Potassium and natural sugars | |
| 5 | Water | 1.00 Reference baseline | |
| 6 | Tea (black, no sugar) | 0.96 Minimal diuretic effect at normal doses | |
| 7 | Coffee | 0.95 Mild caffeine diuretic offset by fluid | |
| 8 | Sports Drinks | 1.05 Electrolytes and carbohydrates | |
| 9 | Beer (low ABV) | 0.90 Alcohol's diuretic effect is dose-dependent | |
| 10 | Sparkling Water | 0.99 Virtually identical to still water |
Top Hydrating Drink Categories Explained
Milk and Dairy Drinks
Milk ranks highest on the BHI because it contains lactose (a sugar that slows gastric emptying), protein (casein and whey), sodium, and potassium. These nutrients cause the body to retain fluid longer than plain water. Skim milk slightly outperforms whole milk in some studies.
Electrolyte Solutions (ORS & Sports Drinks)
Oral rehydration solutions contain the WHO-recommended ratio of sodium, glucose, and potassium optimized for intestinal absorption. Sports drinks like Gatorade contain lower electrolyte concentrations but still outperform water for retention. Best used during heavy sweating or illness.
Coconut Water
Often called nature's sports drink, coconut water contains approximately 600 mg of potassium per cup, along with natural sugars, magnesium, and some sodium. It hydrates comparably to commercial sports drinks for mild to moderate exercise but may lack sufficient sodium for heavy sweating.
Fruit Juices and Smoothies
Orange juice, watermelon juice, and other fruit-based drinks score well due to their natural sugar and potassium content. The caloric load slows stomach emptying, extending fluid absorption. Diluting juice 50/50 with water optimizes hydration while reducing sugar intake.
Drinks That Are Less Hydrating Than You Think
Alcohol
Alcohol inhibits antidiuretic hormone (ADH/vasopressin), causing the kidneys to excrete more fluid. Beer (4-5% ABV) has a mild net-negative effect, but spirits and wine (12-40% ABV) are significantly dehydrating. For every alcoholic drink, aim to drink an equal volume of water.
High-Sugar Sodas
While the fluid content of soda contributes to hydration, excessive sugar (39g per 12-oz can) can cause osmotic shifts in the gut, potentially pulling water into the intestines and causing digestive discomfort. Diet soda hydrates similarly to water.
Energy Drinks
High caffeine content (150-300 mg per can) combined with sugar and other stimulants makes energy drinks a less efficient hydration choice. The diuretic effect at these caffeine levels is more pronounced than with coffee.
Protein Shakes (concentrated)
Very high-protein drinks increase urea production, which requires extra water for kidney excretion. While the fluid content helps, concentrated protein shakes should be accompanied by additional water intake.
Smart Hydration Strategies by Situation
- For everyday hydration, plain water remains the simplest and most accessible choice
- After exercise lasting over 60 minutes, choose drinks with electrolytes to replace sodium and potassium lost in sweat
- When recovering from illness with vomiting or diarrhea, use oral rehydration solutions rather than plain water or sports drinks
- For a hydrating snack, whole fruits like watermelon (92% water) and cucumbers (96% water) provide fluid plus fiber and nutrients
- If you dislike plain water, try herbal teas, infused water, or diluted juice as effective alternatives
- Milk is an excellent post-exercise recovery drink that hydrates better than water while providing protein for muscle repair
- Start your morning with 16 oz of water before any caffeinated beverages to rehydrate after overnight fluid loss
Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. Hydration needs vary by individual, activity level, climate, and health conditions. People with kidney disease, diabetes, or lactose intolerance should consult their healthcare provider about optimal beverage choices.
Frequently Asked Questions
Is milk really more hydrating than water?
According to the Beverage Hydration Index research, yes. Milk's combination of lactose, protein, fat, and electrolytes causes the body to retain its fluid content longer than plain water. Skim milk scored 1.58 on the BHI compared to water's baseline of 1.00. This does not mean you should replace water with milk, but it shows milk is an excellent hydration option.
Are sports drinks better than water for hydration?
For everyday hydration, water is sufficient and has zero calories. Sports drinks are better than water specifically when you are sweating heavily for over 60 minutes, as they replace lost sodium, potassium, and provide carbohydrates for energy. For light activity or sedentary periods, sports drinks add unnecessary sugar and calories.
Does sparkling water hydrate as well as still water?
Yes. Research confirms that sparkling water hydrates virtually identically to still water, scoring 0.99 on the Beverage Hydration Index (compared to 1.00 for still water). The carbonation does not impair fluid absorption. Some people find sparkling water helps them drink more fluid because they enjoy it more.
What is the single most hydrating drink?
Oral rehydration solutions (ORS) are the most efficiently absorbed fluid, designed with the optimal ratio of sodium, glucose, and water for intestinal absorption. However, for healthy individuals with normal hydration needs, skim milk, water, and herbal tea are all excellent everyday choices. The best hydrating drink is the one you will consistently consume.
Does temperature affect how well a drink hydrates you?
Temperature has a minimal effect on hydration efficiency. Cold drinks may empty from the stomach slightly faster, but the difference in total fluid absorption is negligible. The most important factor is drinking enough total volume. Choose whatever temperature encourages you to drink more.
Log Every Beverage You Drink
Vari lets you track water, coffee, tea, juice, and more so you can see your total daily hydration from all sources.