Do Protein Shakes Make You Poop?

Photo of author
Written By Nicolette
Nicolette has been a certified dietician and nutritionist for over ten years, whose work has been featured in the likes of Reader’s Digest, Eat This, Not That, Everyday Health, and Shape. She believes in emphasizing a holistic approach toward food and nutrition.

Have you been hitting the gym hard and recently added protein shakes to help you achieve your fitness goals? If so, you’re not alone! Protein powder is a popular and delicious supplement. But do protein shakes make you poop?

Have you noticed changes in your bathroom habits since increasing your protein intake? Do you find yourself running to the toilet more frequently or feeling constipated? It’s a question many of my clients have asked me when they have recently increased the amount of protein they consume.

I’ll explore the connection between protein and bowel movements to answer this question. And explore the research into whether consuming protein powder makes you poop?

Do protein shakes cause bowel movements?

Protein shakes can lead to increased bowel movements, but only if consumed excessively or if you have underlying medical conditions. Protein shakes may also cause you to poop more or become constipated if you are dehydrated, lactose intolerant, or do not consume enough fiber in your diet.

Let’s look at why protein shakes could be causing you to increase your defecation.

Reasons Protein Shakes are Making You Poop More:

If you are lactose intolerant

If you are lactose intolerant, you will know this already, you cannot properly digest lactose, a sugar found in milk and dairy products. Unfortunately, you might not know you are. And considering the most famous protein in the market is whey protein, made from cow’s milk. Being lactose intolerant, you may have diarrhea by adding protein shakes to your diet.

Mixing protein powder with either milk or water is recommended when consuming a protein shake, as stated in the instructions on most protein supplement tubs. Mixing it with juice is not recommended by manufacturers, as it can make the taste of your protein shake unappealing.

Additionally, if you are on a calorie-restricted diet, avoiding the added calories that come with fruit juice is best. If lactose intolerant, drinking popular protein shakes such as whey protein may not be an option.

What can you do?

If you want to avoid this, you need to consume lactose-free protein. You can go for soy protein which is a plant-based protein.

Is your protein take excessive?

Everything, including water, is bad for health if taken in excess. Similarly, consuming protein in excess can give you problems like diarrhea. This happens because your body tries to get rid of excess protein, which results in more visits to the bathroom.

What can you do?

If you have been consuming too much protein recently, limit it. Everybody has different protein demands. According to research, a person working out should take 1.6g – 1.7g per kg of weight of the individual.

So, you must calculate the amount of protein your body needs and take the protein according to that. Also, you need to drink enough water to keep yourself hydrated.

If you cannot handle sugar alcohol

Your digestion will be affected directly if you are sensitive to sugar alcohol. Protein powders are supposed to be sweet to maintain their taste, but using sugar can be unhealthy. So, the added sugar and alcohol to these products can cause digestion problems.

What can you do?

To save yourself from this, make sure that you are checking all the ingredients before buying your protein. The ingredients should not have the following:

  • Mannitol
  • Sorbitol
  • Xylitol
  • Lactitol
  • Isomalt
  • Maltitol
  • Hydrogenated starch hydrolysates (HSH). 

To make it sweet, you can look for a protein powder with stevia or sugar. 

Your protein has less fiber

If you lack fiber, the protein you have been taking might not make you poop a lot. Interestingly, it might make you feel constipated. The fiber in your food helps with digestion.

However, your protein, which lacks fiber, makes your stool dry. This results in your bowel taking the water from the gut lumen, which makes the stool very hard to pass through.

What can you do?

Add fresh fruits, salads, seeds, and protein shake to your diet to avoid this situation. This will balance the demand for fiber by your body and might help you with constipation. You can also increase the amount of water you have been drinking to help the poop to pass through.

Cannot digest gluten

Some of our bowels have a hard time digesting gluten. This protein is found in several grains. Additionally, gluten can activate your immune system’s attack mode and cause constipation. This can also indicate your celiac disease, which is a digestion-related problem. 

What can you do?

Gluten is found in wheat, barley grain, and rye. So, if your proteins have these, you better refrain from using them. You can also opt for premade shakes not made from such grains. 

To make sure of it, you need to check the shake’s ingredients and ensure that it is gluten-free.

Why Some People Experience Diarrhea When Adding Protein Shakes to Their Diet

Do Protein Shakes Make You Poop

Diarrhea is a less common but possible lousy effect of drinking protein shakes. Lactose is the carb that makes up most of the whey protein.

Some people may not be able to absorb lactose well. As you know, this is called lactose intolerant in the medical world. This happens when our bodies don’t make enough lactase enzymes, which are usually used to help break down lactose. 

When lactose-intolerant people drink protein shakes, their intestines do not take in lactose. Lactose that hasn’t been broken down goes to our large intestine, which mixes with bacteria and causes digestive problems like bloating, gas, and diarrhea.

What can you do?

The condition of lactose intolerance is broad and can be avoided by avoiding dairy products. I would advise you to switch to a whey protein isolate. This might help in reducing gastrointestinal discomfort.

A whey protein isolate is a more refined form of whey protein powder with barely any fat or lactose. Protein shakes made from a plant-based protein are another option.

Does Whey Protein Go to Waste If You Get Constipated After Drinking It?

It’s possible that your body can still digest the protein in the powder. This means that the amino acids from the protein can still be absorbed and function as intended. 

However, in doing so, if this causes you digestive discomfort, it is probably not worth it to keep using that protein powder.

What can you do?

Ensure you’re drinking enough water and eating enough fiber-rich foods, and consider switching from pure whey to a slower-digesting protein source, such as casein protein.

Top Five Tips to Avoid Protein-Related Excrement Problems

1. Stay hydrated

Drink enough water throughout the day to keep things moving smoothly. Proper hydration is essential for proper digestion and bowel movement.

2. Get your daily dose of fiber

Include plenty of fruits, vegetables, and whole grains to increase your fiber intake. Fiber helps to promote regular bowel movements and can help prevent constipation.

3. Don’t overdo it with protein

Consuming too much protein can lead to constipation, so be mindful of your protein intake and consider spreading it throughout the day.

4. Experiment with different types of protein

Whey protein supplements may cause digestive symptoms in people with lactose intolerance. If you experience uncomfortable symptoms or that whey protein causes constipation consider eating high-protein foods instead. You could try switching to whey isolate powder or a non-dairy protein powder. Switching to a slower-digesting protein source, such as casein or soy protein, may suit your digestive system better.

5. Time your protein intake

Avoid consuming protein powder close to bedtime, which can cause indigestion and affect sleep.

FAQ on pooping after a protein shake

​Why Can High-Protein Diets Cause Constipation Or Diarrhea?

High-protein diets can cause constipation or diarrhea for a variety of reasons. One reason is that protein is harder to digest than carbohydrates. It can take longer for the body to break down and absorb the nutrients, which can cause a delay in bowel movements.

Another reason is that high-protein diets may not provide enough fiber, which is essential for maintaining regular bowel movements. Also, some people are intolerant to specific proteins, such as the lactose in dairy products, which can cause stomach upset, bloating, and diarrhea.

Are There Any Added Benefits of Protein Shakes versus Consuming Real Food?

Protein shakes can be a convenient way to increase protein intake, especially for those who have busy lifestyles or have difficulty getting enough protein from whole foods. They can benefit individuals trying to gain muscle mass, but it’s important to note that natural, whole foods can also provide essential nutrients that protein shakes may not contain. In particular, many manufactured ready-to-drink protein shakes have very little fiber. 

On the other hand, whole foods contain fiber, vitamins, and minerals important for overall health. Getting a balance of different types of nutrients will help prevent nutrient deficiencies. So don’t just switch your diet to protein or meal replacement supplements.

You might even get the same, if not better, with natural food alternatives.

How Do Protein Shakes Affect Your Stomach?

Protein shakes can affect your stomach in various ways, depending on factors such as the amount consumed, the quality of the protein, and any underlying health conditions you may have.

Consuming excessive or low-quality protein can lead to stomach discomfort, bloating, and gas. People who are lactose intolerant may experience stomach upset if they consume protein shakes that contain lactose. On the other hand, consuming moderate amounts of high-quality protein from a reputable source may aid digestion, reduce hunger, and keep you full for longer.

Does Too Much Protein Cause Side Effects?

Too much protein can cause several side effects, such as stomach upset, bloating, gas, and constipation. It can also put a strain on your kidneys, which can cause kidney damage over time. Additionally, excessive protein intake can lead to an imbalanced diet, as you may consume less of other important nutrients.

The recommended daily protein intake varies depending on age, sex, and activity level. What might be too much protein for you may not be enough for someone else to achieve their fitness goals.

Will My Morning Protein Shake Have a Coffee-Like Influence on My Bowels?

It’s possible that your morning protein shake could have a similar effect on your bowels as coffee does. Whether or not it does would depend on your tolerance to caffeine or other ingredients that might have a stimulating effect, as well as your overall diet and lifestyle.

The best way to find out is to pay attention to how your body reacts after you drink it and make any adjustments.

How Much Protein is Too much?

Men’s and women’s recommended daily protein intake is suggested at 0.8 grams per kilogram of body weight per day. Some athletes and bodybuilders admit to consuming 3-4 grams per kilogram of body weight per day.

Suppose you have optimized your hydration levels and fiber consumption and are not suffering constipation or excessive bowel movement. In that case, you may increase your protein intake above the level or the general recommendation.

Many studies examine the ideal ratio; however, how much is too much is worth experimenting with both from a tolerance and individual fitness goal and performance perspective. Figuring out whether you are overeating protein is up to you to test and figure out based on your fitness requirements.

Are High-Protein Diets Safe?

High-protein diets can be safe for most people if followed correctly. However, you must ensure you get protein from various sources, not just red meat or protein shakes. Try to balance your diet with plenty of fruits, vegetables, and whole grains. 

What Protein Supplements Could I Take If I am Lactose Intolerant?

  • Pea protein supplements
  • Soy protein supplements
  • Rice protein supplements
  • Egg white protein supplements
  • Hemp protein supplements

These are all alternative protein sources to milk-based proteins, such as whey or casein, suitable for lactose-intolerant people. They are also good options for vegetarians and vegans. They are easy to digest and provide a high-quality source of protein.

However, be warned – the taste or texture may not be what you are used to with Whey. But again, this is the compromise you, unfortunately, must endure if you are lactose intolerant.

Key Points

Does protein make you poop?

  • Protein shakes can lead to increased bowel movements, but only if consumed excessively or if you have underlying medical conditions.
  • Avoid whey or milk-based protein supplements and use more plant-based ones if lactose is intolerant.
  • To avoid over-excreting or constipation when supplementing with protein shakes, be hydrated and consume enough fiber in your diet.


Supporting Research

Phillips, S. M., & Van Loon, L. J. (2002). What Are the Dietary Protein Requirements of Physically Active Individuals? New Evidence on the Effects of Exercise on Protein Utilization During Post-Exercise Recovery. Journal of Nutrition, 132(8), 3214S-3224S.

U.S. National Library of Medicine. (2022). Celiac disease – sprue. MedlinePlus Medical Encyclopedia. Retrieved from

Silanikove, N., Leitner, G., & Merin, U. (year). The Interrelationships between Lactose Intolerance and the Modern Dairy Industry: Global Perspectives in Evolutional and Historical Backgrounds.

Photo of author

Written By


Nicolette has been a certified dietician and nutritionist for over ten years, whose work has been featured in the likes of Reader’s Digest, Eat This, Not That, Everyday Health, and Shape. She believes in emphasizing a holistic approach toward food and nutrition.