Does Mass Gainer Make You Poop?

January 9, 2024 |

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In this article, I will discuss if and why mass gainers can make you poop more often than usual.

Some mass gainer ingredients can overload your gastrointestinal system, making you poop more often. Besides that, these compounds can disturb gut function, leading to bloating, constipation, or smelly farts.

The sections below cover the underlying reasons for these bowel irregularities. Plus, you would find some easy ways to prevent these adversities.

So, stay tuned and read on till the end to find out the solution;

Why Does Mass Gainer Make You Poop?

Mass gainers can make you frequently poop due to multiple reasons. Some individuals are more susceptible to this problem than others, like those who are milk intolerant or gluten allergic.

However, non-allergic people can also suffer from bowel problems after using gainers.

Following are the reasons these supplements can make anyone visit the bathroom frequently;

Presence of Lactose

Lactose molecules conjugated with milk proteins (whey, casein proteins) are the primary cause of bowel disturbance in people with lactase deficiency. These individuals cannot produce lactase enzymes (to digest lactose) in their intestines.

Resultantly, lactose stays in the gut and interacts with microbes present over there.

Bacterial reactions convert lactose molecules into methane and carbon dioxide, which impair normal digestive functions, causing abdominal pain and diarrhea.

A review of scientific literature confirms that lactose intake is responsible for many GI problems, including frequent, loose stools.

Inclusion of Gluten

Just like lactose intolerant people face digestive stress after consuming dairy, gluten-intolerant people face troubles after eating cereals and grains that contain gluten.

Gainer supplements are carb-rich products and their carbohydrate content is derived from different sources. Hence, most are not gluten-free and may cause frequent poops.

A gastroenterological study shows that gluten-sensitive people may suffer from diarrhea upon using gluten carbs.

Addition of Artificial sweeteners

Most gainers contain artificial flavoring to balance the bland taste of the supplement and make them palatable, but this taste-fix comes with the disadvantage of digestive unrest.

Our gut does not have the enzymes to break down most artificial sweeteners used in the market.

Resultantly, these molecules stay in the gut and come in contact with intestinal bacteria, which start fermenting them. Products of this fermentation are usually foul-smelling and harmful to the gut lining.

Hence, bowel movement is disturbed, and you will likely suffer from diarrhea if you take a high dose of sweeteners (by consuming large mass gainer servings).

Presence of Creatine

The growth-promoting amino acid creatine is another cause of mass gainer diarrhea. It disturbs the normal fluid balance in the gut lining, making absorptive tissues either work excessively or poorly.

And in case of malfunctioning, most of the water passes along with feces through the large intestine. Resultantly, you get loose stools frequently.

A study on athletes stated diarrhea as the most frequent adverse effect of creatine supplementation. It concluded that a 10-gram creatine intake could increase the chances of diarrhea by many folds.

High-calorie servings

Another reason you may go to the toilet more often after taking a mass gainer is that you have dumped more calories and nutrients into your gut than it can effectively digest and absorb.

When your intestinal tissues are overloaded, they can absorb nutrients past a certain limit. Hence, the rest of the material passes out as feces.

Can mass gainer cause constipation?

Yes, taking mass gainers can increase the probability of constipation, especially if you do not take enough fiber and water in your routine diet.

The culprit behind this defecation unrest is your favorite ingredient of the supplement – PROTEIN!

Protein molecules take longer to digest than carbs, making bowel movements slower.

However, intestinal walls continuously absorb water molecules, and fecal substance gets harder gradually. As a result, getting rid of these hard stools becomes difficult.

The osmotic amino acids in the gainer further augment the process as they can increase water retention in gut muscles, making stools even harder.

However, you can escape constipation from high-protein content by adjusting your diet plan consciously. Tips in the last section can help you fix this problem.

Besides high-protein, mass gainer constipation can also result from food intolerance. As these supplements contain many whey and carb components, they can upset your gut if you are sensitive to dairy or gluten products.

Why does mass gainer make me fart?

Artificial sweeteners are a primary cause of mass gainer farts. As we know, these molecules are fermented by gut microbes, and the fermentation products are often bad-smelling gases.

Hence, you often become gassy after taking a gaining drink.

Similarly, whey proteins and lactose are also popular for casing flatulence. This problem is found in all population segments but worsens in lactose intolerant people.

Along with bowel problems, mass gainers can make you feel sick in other ways too.

Read my findings on ‘mass gainer side effects’ for detailed information regarding multiple side effects mass gainers can cause.

How to avoid mass gainer bowel problems?

With the following tips, you can prevent gut unrest and the problems mentioned earlier when using a mass gainer;

Take multiple, small servings

As we discussed above, one of the main reasons mass gainers make you poop is that you have suddenly started taking too many calories. And your digestive system is not accustomed to utilizing all the nutrients you have started taking.

An easy remedy is to start with small doses or at least lower the serving size and take multiple servings if you want a bulk of calories from your supplement daily.

For example, if you want to consume a mass gainer worth 600 calories, its per scoop content is about 300 calories. You should take two shakes at a different time of the day, each containing one scoop, instead of having a 600kcal drink in one go.

In this way, your body can manage the calorie content easily, and the risk of overdosing on proteins and artificial sweeteners is also reduced.

Drink more water

Your bowel movements are significantly affected by the fluid balance in your body. This balance can be upset when you make major dietary changes like converting to a high-calorie, high-protein diet without adjusting your water intake.

More protein intake increases water utilization in the body and may lead to dehydration. In turn, dehydration can slow down digestion and is also a potential cause of constipation.

Hence, if you are taking mass gainers, it is best to increase your daily water intake so that your digestive system can properly manage its functions.

What I recommend is to make hydration a fun activity!

Try fun options like infused water, green teas, coconut water, lemonades, and fruit juices. This makes the process more enjoyable and also adds many nutritional benefits.

Use Probiotics

Probiotics are the friendly microbes in various food items that positively affect the gut microbiome.

And if your gut microbiota is healthy and flourishing, you can escape most digestive troubles, including bowel irregularities.

Scientific evidence proves that probiotic intake helps prevent constipation and diarrhea. Moreover, probiotics are often recommended to treat acute diarrhea.

And besides probiotics, you can also help your friendly gut bacteria by taking some prebiotics because these ingredients act as food for gut microbes.

You can buy probiotic and prebiotic supplements, but the best way to get them is through natural food.

Here is a small list of food items to help you with this selection;

pro & prebiotic sources

Try Green tea

Green tea is a highly effective way to cure bowel problems like frequent loose poops, and it also helps you increase your water intake.

Plus, herbal extracts increase the absorptive ratio of different nutrients in the bloodstream.

Ginger, chamomile, fennel, fresh mint, and cinnamon tea are some of the most effective green tea options that prevent and relieve gut problems.

And the best thing about this drink is you can make it with an easy, all-rounder recipe no matter what flavor you want. Here is how you can do it;

  • Simmer a cup of water and put some pieces of your desired herb (ginger, mint, cinnamon, etc.) into it.
  • Let it boil for a few minutes.
  • Add a spoonful of honey, maple syrup, or a pinch of sugar to sweeten it. Honey is the best option because it contains prebiotics and antioxidants.
  • And Voila! Your soothing drink is ready in less than five minutes.

Add fiber to your diet

Eating fibrous foods can also prevent bowel irregularities because dietary fiber maintains the consistency of bowel movements. It is especially effective in preventing constipation.

Choose the right mass gainer supplement

Last but not least, you can avoid many side effects if you go for a quality product that suits your personal needs. If you are a lactose intolerant person, choosing a lactose-free product would likely reduce the risk of frequent poops and farts.

Likewise, if you are gluten allergic, the best approach is to look for a gluten-free gainer. If you think artificial flavors are causing trouble, try an unflavored, unsweetened product.

However, such products are rare, and you also miss some of the great benefits of quitting whey components or grain carbs. One product that we have found beneficial in this respect is CrazyNutrition Mass Gainer.

CrazyNutrition Mass Gainer bottle

It is my number one recommendation for gaining lean mass due to multiple reasons. The first one is DigiZyme Complex- a blend of five enzymes, including lactase, cellulose, amylase, protease, and lipase.

This blend helps you digest whey components even if you suffer from milk intolerance.

Besides milk, it has no other allergens. However, it do contains a good amount of healthy low glycemic carbs from gluten-free oat flour, flaxseeds powder, and Carb10 (pea starch).

Thus, you get a healthy, gluten-free boost in your calorie intake.

To further reduce the probability of digestive problems, it contains herbal extracts from Panax, Rosa roxburghii, and Astragalus, which help its high-calorie ingredients absorb faster.

So, in my opinion, this mass gainer is the best product out there as it does not make you sick with GI ailments.


Mass gainers can disturb normal bowel movements, especially in people who cannot digest lactose or gluten properly in their intestines.

In addition, artificial sweeteners, high-calorie count, and creatine-rich formulations can also cause mass gainers, making you poop repeatedly.

However, you can minimize this trouble by making suitable changes to your diet, like drinking a lot of water, consuming more fiber, and taking multiple but small doses of the gaining supplement.


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