How to Choose Between Milk or Water for Your Protein Shake

Whether you're sipping a post-workout shake or blending a quick meal replacement, how you mix your protein powder matters. The two most common choices milk and water offer very different experiences when it comes to taste, texture, and nutritional impact. But is one really better than the other?

According to registered dietitians, both milk and water have their benefits and your personal goals should guide your choice.

Mixing Protein Powder With Water: Light and Lean

Water is calorie-free, making it an ideal base if you're aiming to lose weight or reduce your daily intake. It also digests quickly and won’t add extra fat, sugar, or carbs to your shake.

Benefits of using water include:

• Zero calories, which helps with weight management

• Faster digestion, ideal for a pre- or post-workout shake

• Fewer stomach issues, especially for those with dairy sensitivity

• Convenience, since it doesn’t require refrigeration

Registered dietitian Kevin Park, RDN, explains that water is a safe, easy choice that keeps things simple and light. “It’s also ideal if you're using a flavored protein powder and want to avoid altering the taste,” he notes.

Mixing Protein Powder With Milk: Creamy and Nutrient-Dense

Milk especially dairy milk adds a creamy texture and richer flavor to protein shakes. It also provides essential nutrients that support muscle recovery and energy levels.

One cup of dairy milk typically contains:

• 8 grams of protein

• 12 grams of carbohydrates

• Calcium, potassium, and vitamin D

• Casein, a slow-digesting protein that supports sustained muscle repair

If you're using protein shakes to build muscle, replace a meal, or recover after workouts, milk may be the better option. It not only boosts the shake’s protein content but also delivers longer-lasting energy. Park adds, “You’re gaining more, longer-lasting fuel from the extra nutrients.”

How Different Protein Powders React to Liquids

The type of protein powder you use also plays a role in choosing the right liquid. According to Yasi Ansari, RDN, protein powders made from plant-based sources like soy, pea, or hemp tend to absorb more liquid and need 10–12 ounces of milk or water for best results. Whey or casein protein, derived from milk, typically mixes well with just 8 ounces of liquid.

Plant-Based Milks: A Middle Ground

For those avoiding dairy or looking for a lighter option with more flavor than water, plant-based milks are a great compromise. Many are fortified with essential nutrients like calcium and vitamin D and offer a variety of textures and benefits.

Here’s a quick breakdown of popular plant milks:

• Soy milk: Highest in protein (around 6–7g per cup)

• Oat milk: Creamy, with added fiber and moderate calories

• Almond milk: Light and low in calories, but only 1–2g of protein

• Coconut milk: Very low in carbs, but also low in protein

"Each plant-based milk offers unique benefits, and the choice depends on your dietary needs and taste preferences," says Ansari.

So, Which One Is Better?

There’s no single right answer it all depends on your personal health goals and dietary preferences.

Choose water if you:

• Are watching calories or trying to lose weight

• Want fast digestion

• Have dairy intolerance or sensitive digestion

• Need a quick, convenient shake

Choose milk if you:

• Need a meal replacement or extra fuel

• Are looking to build muscle or recover after workouts

• Want a creamier, more satisfying shake

• Prefer a nutrient boost from calcium and vitamin D

Choose plant-based milk if you:

• Avoid dairy for personal or health reasons

• Want more flavor and texture than water, but fewer calories than dairy

• Are seeking plant-powered nutrition with added benefits like fiber or lower sugar

The Bottom Line

Milk makes your shake richer and more nutritious, while water keeps it lean and easy on the stomach. The best option depends on your body’s needs and your daily goals—whether that’s gaining strength, staying energized, or keeping calories in check.

Share this article or subscribe to our newsletter for more science-backed wellness insights.