Absolutely… but you should be having more than just the protein powder and water. Try adding some complex carbs and/or healthy fats so that you’re getting a more well-rounded meal and you won’t be starving within an hour. Also, if you’re going to replace a meal with protein powder, opt for a slower digesting variety such as Casein as opposed to Whey. (Whey digests quickly and will be out of your system in about an hour).
Some healthy carb options to add to your shake would be spinach, kale, berries, strawberries, blueberries, raspberries, an apple, a banana, oats, or yams.
Some healthy fat options to add to your protein shake might be avocado (great in green smoothies), natural peanut butter, natural almond butter, coconut oil, flaxseed oil or ground flaxseed.
Also consider using unsweetened almond milk or sugar free coconut milk instead of water to make it even more filling!