Does Whey Protein Cause Constipation?

Whey protein powder is known to have various advantages, from muscle growth to an increase in daily protein intake. However, it also causes digestive issues like constipation, protein fats, and even bloating. It may result from the mode of preparation or the brand you are taking.

Constipation through the intake of whey protein might also result from taking too much of it. So, it is pertinent that you consider the brand, the way you prepare it, and the usual dose required per day.

If you’re interested, read more about the causes of constipation due to whey protein intake.

Does Whey Protein Cause Constipation?

Whey protein supplements cause constipation, but it mostly depends on the person taking them. The probabilities of constipation from whey protein powders also sometimes rely on the brand.

Too much protein sometimes contributes to constipation, so we always recommend staying within the prescribed dose of protein intake daily. However, we advise that if you often get constipated from the intake of whey protein, reduce the intake and ensure you get enough fiber from vegetables and fruits.

We also recommend that you stay hydrated when you are on a high-protein diet and seek the advice of a professional medical expert as to how to deal with the issue.

Causes of Constipation via Whey Protein Powder

Does Whey Protein Cause Constipation?

Lactose Intolerance

Lactose intolerance is a significant reason individuals tend to be constipated when taking whey protein regularly. Lactose intolerant people are open to side effects regarding whey protein.

The most popular forms of supplemental protein, whey and casein, contain milk and can be harmful if a person is incapable of digesting lactose. However, they can address this issue by switching to a lactose-free protein powder or mixing the whey protein powder with almond milk or water.

If this approach does not work, you can try to find another cause of the problem.

Sugar Alcohols

Most people’s system does not agree with a high quantity of sugar, even though dietary supplement manufacturers need to make their protein powder taste good.

Sugar alcohols are those low-calorie sugar substitutes that trigger blood sugar in the process of contributing to the sweetness and weight of whey protein powder. So, it is pertinent to consider if the ingredients of your protein powder contain sugar alcohol like sorbitol, whey protein hydrolysate, isomalt, maltitol, mannitol, and xylitol.

However, you can fix this problem by switching to sugar alcohol-free whey protein powder. You can also go for protein powders sweetened with sugar or stevia.

Low or High Fiber

Another leading cause of constipation when drinking whey protein shakes is the absence of fiber or too much fiber. Low fiber leads to constipation by hindering the flow of your stool. Too much fiber, on the other hand, leads to constipation by stocking your stool and rendering it very hard to pass. 

Notwithstanding the general notion that a person should go for a protein powder high in fiber, it is essential to note that it contains primary soluble fiber that stocks up one’s stool. However, you can fix this by taking enough water or going for a lower-fiber protein powder with five grams or less fiber per serving.

More Protein Shakes, Less Whole Foods

Constipation can also result from insufficient vitamins and minerals from whole foods. Vitamins and minerals help with healthy digestion, and constipation happens when they are absent.

Taking fewer whole foods like vegetables and fruits while consuming more protein shakes will undoubtedly lead to constipation. You can address this by increasing the consumption of whole foods and reducing the intake of any whey protein supplement.


How the whey protein powder is prepared also leads to constipation or other digestive problems. Exposing the powder to air during preparation can hinder its digestion after consumption.

Address this lapse by ensuring that you avoid the presence of air during the preparation of the protein shake.

Low-carb Whey Protein

Whey protein with too few carbohydrates can eventually cause gas and constipation as protein takes more time before digesting than carbohydrates. The higher the number of carbohydrates in your protein shake, the sooner it will vanish from your stomach.

You can combat this by switching to a protein powder that digests quickly, like soy.

How to Prevent Constipation From Whey Protein Isolate Consumption

Stay Hydrated

A lack of water or low water concentration causes protein powder constipation, making it pertinent to drink enough water all the time.

Athletes and bodybuilders mainly consume whey protein to increase their performance during training. However, this implies that they tend to sweat more than any other person. As a result, we often advise those who consume more protein shakes should take enough water to replace the ones they lose by sweating during training.

Also, it is essential to note that too much intake can lead to dehydration. Therefore, one should not go beyond the prescribed dose.

Consume a Moderate Quantity of Fiber

Fiber is a consumable part of plants and carbohydrates that do not digest easily. You can also obtain it from plants, fruits, vegetables, grains, nuts, legumes and seeds.

There are two types of fiber: soluble and insoluble fiber. Soluble fiber includes carrots, oranges, peas, beans, lemon, etc. Meanwhile, insoluble fiber includes cauliflower, wheat flour, potatoes, wheat bran, etc.

Soluble fiber is known to slow digestion, while insoluble fiber hastens the process. Therefore, we recommend consuming a moderate quantity of fiber to prevent protein powder constipation.

Frequently Asked Questions

Does protein make you poop?

High protein diets can cause diarrhea or make you poop since some people resort to processed and dairy foods to meet their protein targets.

However, to avoid diarrhea that results from whey protein intake, go for a dairy-free, sugar-alcohol-free, and additive-free protein powder. You can also switch to a protein powder low in insoluble fiber.

How much is whey protein safe per day?

Whey protein, which contains essential amino acids, is known to be relatively safe for intake by various people without any occurring side effects. Going by the saying “too much of everything is terrible,” there is a recommended daily dose.

1-2 scoops, equivalent to 25-50 grams per day, are the recommended daily whey protein powder dose. Also, we advise that you check the package of the whey protein product to see if there is a prescribed dose. If there is, go by it.

Is whey protein harmful to the kidney?

Too much whey protein can hinder your kidneys’ proper functioning through urinary volume, calcium excretion, and plasma urea content. As a result, it puts pressure on the kidney and eventually causes kidney stones. 

To neutralize this side effect of whey protein, take enough water and fiber.


Does Whey Protein Cause Constipation?

Whey protein powder causes constipation depending on the person consuming it, the quantity consumed, and how you prepare it. This article has carefully laid down the causes of whey protein powder constipation and the various ways to avoid it. 

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Nathan Lloyd, MSc

I’m a personal trainer, based in Boulder, Colorado.
I service clients physically in the Boulder area, mainly in the ONE Boulder Fitness Gym, but am also available for online consulting and coaching.

If you’re interested in my personal coaching programs, please contact me via the contact page.