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If you’re taking protein shakes and noticing that you feel extra thirsty, you’re not alone. I’ve had clients and friends at the gym ask me what’s up with feeling like they just can’t drink enough water after their protein shakes.
But are protein shakes actually the cause for feeling so thirsty? No, protein shakes are rarely the sole reason why you feel more thirsty. Increased thirst is more likely due to a combination of factors such as sweating more due to longer, more intense training sessions, changes in carb and fiber intake, and environmental factors.
To help you troubleshoot why you’re feeling so dehydrated and what to do about it, I’ll discuss the following in this article:
- What scientific studies say about protein intake & dehydration
- 7 reasons why you might feel more thirsty
- How much water to drink when taking protein powder
- What else to consider if you’re thirsty after drinking protein shakes
Protein Shakes & Dehydration: What’s the Connection?
The current scientific studies on protein intake and dehydration don’t look specifically at protein shakes or protein powders, just overall protein intake and dehydration.
Based on these studies, individuals with extremely high protein intakes have shown signs of dehydration. However, the effects are insignificant and not just because of a higher protein intake.
As an example, endurance athletes following an extremely high protein diet (246g of protein per day for an athlete weighing 150lbs, or 1.6g of protein per pound of body weight) showed signs of dehydration through more concentrated urine, but they didn’t feel more thirsty.
As such, with a high protein intake, the athletes’ kidneys had to work harder to clear away the waste products that are left over when the body breaks down protein.
But as endurance athletes, they also would have had a high training load, which creates additional metabolic waste products in the body for the kidneys to deal with.
Another more recent study also analyzed individuals who consumed 1.6g of protein per pound of body weight. Researchers noted a higher amount of nitrogen in the participants’ urine but concluded that high protein intake had a minimal effect on hydration.
Key Takeaway: It’s probably not the whey protein that’s making you feel thirsty after drinking a shake.
7 Reasons Why You’re Thirsty After Drinking Protein Shakes
If you’re thirsty after drinking protein shakes, it is unlikely that your thirst has to do with the added protein. Rather, it’s more likely one or more other factors in addition to your higher protein intake that causes you to feel more thirsty.
1. You’re Consuming Fewer Carbs
Often, an increase in protein intake comes along with a decrease in carb intake, especially for people looking to lose weight or cut body fat. Carbohydrates store water, so as the amount of stored carbohydrate (glycogen) in your body decreases, your body releases stored water.
This explains why many people will see a large initial drop on the scales when they start a low-carb diet.
As body water stores drop, your body will increase thirst signals to bring total body water back into balance.
- Related Article: Drinking Whey Protein On An Empty Stomach – 3 Things To Know
2. You’re Consuming More Carbs
Even though fewer carbs can make you thirsty, more carbs can make you thirsty, too. If you’ve increased both your protein and carbohydrate intake for performance or bulking goals, your body needs more water to assist with digesting a higher overall food volume.
Your total calorie intake may remain the same. But if you now have more calories coming from carbs than before, those carbs will pull water into the cells as part of glycogen storage in your muscles and liver. Your body will increase thirst to meet its needs for water outside of the storage cells.
For example, your blood cells and digestive tract need water. Your body will make you feel thirsty so these needs are met.
- Related Article: Does Creatine Make You Thirsty? 6 Reasons
3. You’re Consuming More Fiber
Using protein powder can be part of an overall change in nutrition to start eating healthier. This can mean you eat more fruits, vegetables, legumes, and whole grains than before, along with adding protein powder.
These fruits, vegetables, legumes, and whole grains will provide more dietary fiber. Dietary fiber draws water into the digestive tract to help move things along. It’s great for helping with digestion, but it can also make you thirsty.
- Related Article: Bodybuilding & Fiber: Everything You Need To Know
4. You’re Moving More
If protein powder is part of a plan to eat healthier, you might also include more activity in your day. Even if you’re not intentionally including more exercise, focusing on eating better can give you more energy, causing you to fidget, take extra steps, and move more in general.
All of this extra movement can increase your respiration rate (breathing) and the small amount of sweating you do during the day. Even when you don’t notice it, you lose small amounts of water throughout the day through your mouth and pores.
Your body will increase your thirst signals to make up for these water losses.
5. You’re Sweating More
If you add protein powder and train harder in the gym to lose weight or gain muscle, you could be sweating more in your workouts, which is making you thirstier.
Or, it could just have to do with the weather. Perhaps you start taking protein powder in the spring as part of your diet plan leading up to the summer. The warmer weather in the spring and summer months could make you sweat more, too.
Regardless of the root reason, if you sweat more, you’ll feel thirstier, and you’ll need to drink more to make up for the water lost through sweat.
6. You’re Using Plant-Based or Sweetened Protein Powder
Compared to animal-based protein powders (like whey protein or egg white protein powder), most plant-based protein powders (rice, pea, hemp, and soy) have a higher carbohydrate content. Or, your protein powder has added carbohydrates from sugars.
As described above, those extra carbs are water-loving. Each gram of carbohydrate will suck in 3-4 grams of water, so the carbs in your protein powder will make you feel thirstier.
7. You’re Significantly Exceeding Protein Targets
If you eat at or above the high end of 1.6g of protein per pound of body weight, your body needs extra water to help the kidneys flush out the waste products that come from digesting so much protein.
Protein intake at 1.6g per pound of body weight would mean a 200lb person eating 320g of protein per day. This level of protein intake is excessive and is not needed to meet performance or body composition goals.
How Much More Water Should You Drink When Supplementing With Protein?
In general, I recommend taking your body weight in pounds and dividing it by two to get the number of ounces of water you should drink each day. You can then adjust as needed based on your thirst and the color of your urine.
Try the amount of water you get from the calculation above for at least 3 days. If you need to pee more than once per hour and your urine is completely clear (colorless and odorless), it is probably too much water.
On the other hand, if you rarely need to pee and your urine is bright or dark in color and/or strong-smelling, it is not enough water.
The goal is to consume enough water so that you pee every 1-2 hours during the day on average, and your urine is pale with little to no odor.
It would be great to be able to provide a formula for exactly how much to drink for every scoop of protein powder, but there are so many variables for each person that I cannot make a sweeping recommendation.
Exercise volume, frequency, and intensity; food choices and quantity; and rate of respiration and perspiration can all impact hydration needs.
For example, some people live in places with very dry climates and lots of indoor heating (which dries the air), which means they will need to drink more water. Other people live in damper climates with high humidity, and they don’t need to drink as much water.
Other Ways To Avoid Dehydration When Consuming Higher Protein
Set Reminders to Drink Water Throughout the Day
Put reminders in your calendar or set an alarm on your phone to go off periodically throughout the day to remind you to drink water.
You can also get a Smart Water Bottle to help keep you on track with your planned water intake for the day.
Consume More Electrolytes
Dehydration isn’t resolved just by drinking more water. When it comes to hydration, beverages containing electrolytes (dissolved salts) and carbohydrates can also help you avoid dehydration. They help draw water into the bloodstream rather than just passing straight through your digestive system and out the other end.
If you’re looking specifically for a sports recovery drink, look for one containing electrolytes and moderate amounts of carbohydrates. Gatorade is a well-known recovery drink for this very reason.
Outside of training, adding electrolytes to water makes it more hydrating than plain water. Check out electrolyte tablets such as LMNT to sprinkle in your water during the day.
Consume Fruits and Vegetables With a High Water Content
I mentioned earlier that consuming more fiber through fruits and vegetables can make you more thirsty.
However, some fruits and vegetables (such as grapes, melons, and tomatoes) have a high water content. Consuming these foods, along with drinking more water, can help you stay hydrated throughout the day.
Certain medications and beverages have a diuretic effect, meaning they increase urination. Coffee and other caffeinated beverages like black tea, soda, or pre-workout energy drinks are known for this.
Avoiding beverages and medications (unless you really need them) that have a diuretic effect can prevent you from feeling thirsty throughout the day.
What To Read Next
- Do Protein Shakes Cause Constipation? (Causes & How To Fix)
- Can Protein Shakes Make You Nauseous? (Yes, Here’s Why)
- Protein Shakes & Diarrhea: Causes + Fixes Explained
Spada, T. C., Silva, J. M. R. D., Francisco, L. S., Marçal, L. J., Antonangelo, L., Zanetta, D. M. T., Yu, L., & Burdmann, E. A. (2018). High intensity resistance training causes muscle damage and increases biomarkers of acute kidney injury in healthy individuals. PloS one, 13(11), e0205791. https://doi.org/10.1371/journal.pone.0205791
Martin, W.F., Cerundolo, L.H., Pikosky, M.A., Gaine, P.C., Maresh, C.M., Armstrong, L.E., Bolster, D.R., & Rodriguez, N.R. (2006). Effects of Dietary Protein Intake on Indexes of Hydration. Journal of the American Dietetic Association, 106(4), 587-589. https://doi.org/10.1016/j.jada.2006.01.011.
Fernández-Elías VE, Ortega JF, Nelson RK, Mora-Rodriguez R. Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans. Eur J Appl Physiol. 2015 Sep;115(9):1919-26. doi: 10.1007/s00421-015-3175-z. Epub 2015 Apr 25. PMID: 25911631.
Millard-Stafford, M.; Snow, T.K.; Jones, M.L.; Suh, H. The Beverage Hydration Index: Influence of Electrolytes, Carbohydrate and Protein. Nutrients 2021, 13, 2933. https://doi.org/10.3390/nu13092933
About The Author
Lauren Graham is a Precision Nutrition Level 1 certified nutrition coach. She focuses on helping busy professionals balance healthy eating and purposeful movement. Lauren has a background in competitive swimming and is currently competing as a CrossFit athlete. She has a passion for training, teaching, and writing.