Can Protein Drinks Cause Upset Stomach?

Protein supplements can fill a gap in your diet, but be wary of their side effects.
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Protein drinks make it easier to boost your protein intake. They're a nutritional supplement that can help if you don't like to eat a lot but need more protein in your diet or if you're vegan or vegetarian. If you have stomach pain after eating protein or a protein supplement, you might be eating too much or having the wrong kind of protein.



Protein powder can upset your stomach if you're allergic to the ingredients or consume too much.

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The Importance of Protein

Think of protein as a building block for your muscles. When you ingest protein your body breaks it down into amino acids, which then float around your bloodstream. Those amino acids can then combine to form muscle tissue wherever it's needed.

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Since muscle is built from protein, it's important to eat protein if you want to build muscle. Meat from animals is abundant in protein. Lean protein sources like chicken and fish are low in fat, whereas red meat sources like beef are high in fat. Plant sources of protein include quinoa, nuts, beans and tofu.

Protein and Weight Loss

Fat, carbohydrates and protein are the three macronutrients. Of those three, protein takes the most energy for your body to digest. In fact, 20 to 30 percent of the energy you get from the protein you eat is spent on digesting the protein itself, according to a 2015 paper published in the The American Journal of Clinical Nutrition.

The same paper also explains that eating protein keeps hunger at bay longer than fat or carbs. That may be due to the fact that protein-rich foods take more energy to break down and digest than carbs or fat. That also means it can be taxing on your digestive system to eat excessive amounts of protein.


How Much Protein to Eat

For the average adult, the Dietary Guidelines for Americans recommends getting 10 to 35 percent of your total calories from protein. This recommendation is vague, which is why some health professionals recommend calculating your protein needs based off your weight.

An article from Harvard Health Publishing recommends eating 1 gram of protein per .36 pounds of bodyweight. All you have to do is multiply your bodyweight in pounds by .36 to find your daily protein needs.


Read more: How Much Protein Is Right For You?

If you're lifting weights and trying to gain muscle, your protein requirements might be a little higher. Weightlifting causes damages and makes the protein in muscle break down. To rebuild the muscle you should have a slightly higher protein intake than normal.


How Much Is Too Much?

A 2018 research study published in the British Journal of Sports Medicine shows that eating over 1.6 grams per kilogram of bodyweight doesn't have any additional benefit. That translates to about .72 grams of protein per pound of bodyweight.


Protein drinks can help you hit this number, but some people are convinced that more protein will be better and consume too much. A 2016 paper published in the Royal Society of Chemistry shows that a long-term diet above 2 grams of protein per kilograms of bodyweight per day can mess with your digestive system. Keep your protein intake in check to avoid stomach discomfort.

Whey Protein Stomach Ache

One of the most popular protein supplements is whey protein. To make whey protein cows are milked, and the milk is sent to a manufacturing facility. Then, the milk is tested for safety. In the process of making cheese from the milk, curds are formed and a liquid separates itself and floats on top. This liquid is taken and dehydrated to turn into powdered whey.


Since it's derived from dairy, whey protein can upset the stomach if you're lactose intolerant. When you're lactose intolerant it means you can't digest the main sugar in dairy, which is lactose. Even if you're not lactose intolerant you might be allergic to dairy. Check with your doctor if you can't figure out why whey protein is making your stomach upset.

Careful With Your Mixer

What you mix your protein powder with can change how taxing it is on your stomach. Whey protein is often mixed with milk. Since it's made from dairy, milk makes the powder taste even better.


However, you might want to mix it with water to make it lighter on your stomach. If you're blending your powder up in a smoothie with other ingredients, try isolating the powder and mixing it with water.


Allergic Reaction to Soy Protein

Opting for a vegetarian source of protein is typically safer for your stomach, especially if you're lactose intolerant. If you've switched, and you're still having problems, check the type of plant-based protein that you're using. If it's made from soy, you could have a soy allergy.


Soy allergy is relatively common. Soy is a legume which puts it in the same family as foods like pinto and black beans. You may also be allergic to these foods if you can't eat soy.

If you're allergic to soy, and you have protein powder containing soy, you'll probably have other symptoms in addition to stomach discomfort. You might have itchy eyes or throat. Itchy hives might develop on your skin, and your chest might feel tight. Check with your doctor to find out if you're allergic to soy.

Protein Timing and Digestive Problems

Since protein can be taxing on your digestive system, you shouldn't have it too close to an intense workout or athletic competition. When you exercise your blood flow is diverted away from your internal organs and out to your muscles. When this happens, your digestive system doesn't get the resources it needs to properly digest food.

That can cause stomach discomfort. Try taking your protein supplement at least two hours before exercise to give it time to digest. You can also save it for after your workout, when your blood begins returning to your digestive system.

Read more: 8 Things to Consider When Choosing a Protein Powder and Our 5 Top Picks

Check for Artificial Sweeteners

Whether you opt for animal or plant protein, beware of artificial sweeteners. While some people can consume sweeteners without adverse effects, some people report stomach discomfort.


It's also possible to develop irritable bowel syndrome from sweeteners such as stevia and sucralose. If your stomach hurts after drinking your protein powder, try switching to a brand that doesn't use sweeteners.

When You Should Switch Brands

It would be nice to be able to trust every single brand of protein powder you see online or on the shelves of your store, but that's not the case. Supplement manufacturing isn't always up to par.

As a supplement, the FDA leaves it up to the manufacturer to ensure the safety of the product. Since the industry isn't tightly regulated, you might not be getting exactly what you think you're getting.

If your protein powder gives you a stomach ache, and you're not allergic to any of the ingredients, try switching brands. You may be consuming mystery ingredients.




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