Do Protein Shakes Make You Poop? What You Need to Know

Protein shakes are a convenient way to nourish your body after a workout or when you’re pressed for time.

They’re popular enough that, according to data from 2016, 46% of Americans report consuming protein drinks and shakes regularly. 

But some people experience gastrointestinal effects that prompt the uncomfortable question—do protein shakes make you poop?

While protein on its own is unlikely to cause a bowel movement, there are some ingredients in protein shakes, like artificial sweeteners, that can cause this effect or other gastrointestinal symptoms. 

Keep reading to learn more about the ingredients in protein shakes and how they may affect your gastrointestinal health. 

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Do Protein Shakes Make You Poop? 

There are several possible ingredients in protein shakes that can affect your gastrointestinal (GI) system, including fiber content, lactose, and artificial sweeteners.

Fiber Content

Protein shakes vary in fiber content. Most protein shakes, especially those made from animal sources of protein, contain little-to-no fiber.

Over time, eating a high-protein diet consisting of low-fiber protein shakes without supplementing your diet with additional sources of fiber can lead to chronic constipation.

On the other hand, some plant-based protein shakes contain higher amounts of fiber, like those made with hemp seed.

Eating more dietary fiber than your body is used to can cause GI symptoms, including bloating, gas, cramps, and increased bowel movements.

Whey and Casein

Protein shakes made from whey and casein contain lactose, which can cause GI upset in people with lactose intolerance.

These symptoms can include bloating, diarrhea, gas, nausea, stomach cramps, and vomiting.  

Other Ingredients

Artificial sweeteners are common ingredients in protein shakes to help keep the carbs and calories low.

Sugar alcohols are a type of sugar-free sweeteners that can be added to protein shakes. 

Examples of sugar alcohols include:

• Sorbitol.
• Xylitol.
• Erythritol.
• Maltitol.
• Isomalt.
• Lactitol.

Though they’re recognized as safe for consumption, they can have a laxative effect in some people, especially when consumed in large amounts.

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Pooping After Eating

Feeling the urge to have a bowel movement soon after eating is a normal physiological response referred to as the gastrocolic reflex. People with gastrocolic reflux feel the need to go to the bathroom after most meals, including protein shakes. 

Gastrocolic reflex is believed to be a symptom of irritable bowel syndrome (IBS). 

Do All Protein Shakes Make You Poop?

No, all protein shakes are not guaranteed to make you poop. If you’re feeling the urge to use the bathroom after drinking a protein shake, consider speaking with your doctor or dietitian about the ingredients included and the effects or symptoms you experience.

If you continue to experience the same urge to defecate after trying multiple kinds of protein shakes, reach out to your doctor.  

Potential Side Effects of Protein Shakes

No protein shake contains exactly the same ingredients.

Depending on your protein shake of choice, you may experience certain side effects after consumption.

Increased Bowel Movements

Drinking protein shakes that contain high amounts of fiber can cause you to have more bowel movements than usual.

Shakes that contain sugar alcohols like sorbitol or xylitol may also cause you to have more bowel movements.

Constipation

Many protein shakes don’t contain much, if any, fiber. Eating a high-protein diet lacking in fiber can lead to constipation.

It’s also important to note that eating too much fiber—including protein shakes rich in fiber—can worsen constipation in some people.

If you’re drinking protein shakes high in fiber, be sure to compensate by drinking plenty of water throughout the day.

Stomach Upset

Drinking protein shakes made from whey or casein can cause stomach upset, including cramps, bloating, and gas, if you are lactose intolerant. 

If you’re not lactose intolerant, there are other potential ingredients in protein shakes that can cause GI distress, including sugar alcohols like sorbitol, maltitol, or xylitol.

How Much Protein is Too Much?

Dietary protein recommendations vary depending on age, activity level, health status, and other factors. 

According to the National Academies of Medicine, most adults should aim to consume a minimum of 0.8 grams of protein for every kilogram of body weight each day. 

If you’re pregnant or breastfeeding, that recommendation increases to 1.1-1.3 grams of protein per kilogram of body weight per day. And if you’re trying to grow muscle, aim for 1.6 grams of protein per kilogram of body weight.

Because muscle mass declines significantly with age, some research suggests that individuals 60 years and older should eat 25-30 grams of protein per meal.

However, eating too much protein can have negative effects on our health.

The risks associated with consuming higher amounts than recommended include:

• Bone loss.
• Impaired kidney function. 
• Increased cancer risk.

To healthfully meet your protein needs, it's important to take several factors into consideration, including your age, weight, activity level, and overall health.

Working with a registered dietitian can help you to determine your optimal daily protein intake according to your unique circumstances.

Tips for Preventing Digestive Issues from Protein Shakes

Finding a protein shake that works well for your health needs and digestive system may take some trial and error.

Regardless of which protein shake you consume, aim to incorporate the following strategies into your routine:

• Drink plenty of water throughout the day.
• Eat a balanced, and nutrient-dense diet that provides adequate amounts of protein, fats, and fibers from a variety of food sources every day. 
• Avoid ingredients that cause GI discomfort, which may include sugar alcohols or lactose (if you have lactose intolerance).

Takeaway

Though protein on its own is unlikely to cause you to have a bowel movement, some ingredients used in protein shakes can cause you to go to the bathroom, like sugar alcohols. 

How a Dietitian Can Help

Working with a registered dietitian will help you find protein shakes that work with your body and help you learn how to incorporate them into a balanced and nutrient-rich diet.

At Nourish, all appointments are done online to make it easier to accommodate your schedule.

In addition to individual counseling, you can also download the Nourish app to access free resources like meal plans and other helpful handouts. 

You can find a dietitian through Nourish to start optimizing your nutrition.