Is Drinking Too Much Whey Protein Dangerous?

When consumed in moderation, whey protein can speed up your progress in the gym and make weight loss easier.
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Whey protein is one of the bestselling sports supplements worldwide. It's a favorite choice for fitness enthusiasts of all ages and types, from weekend warriors to pro bodybuilders to endurance athletes. In fact, it's not uncommon for dieters and gym-goers to replace one or more meals with protein shakes.


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But what happens if you drink too much whey protein? Will you lose weight and build muscle faster, or it is just a waste of money? In this case, the old saying ​"Less is more"​ appears to be true.


When you consume too much protein, the excess is excreted in urine or stored as glycogen and fat. It may also cause digestive problems, especially in those with lactose intolerance.

Is Whey Protein Really Healthy?

Different people consume whey protein for different reasons. Some take the supplement to build mass and strength. Others drink protein shakes to get leaner and stay full longer. Clinical evidence confirms these diet and health benefits.


A 2017 research paper published in the journal Nutrients compared the effects of whey, soy and leucine supplements on body composition and muscular strength. Whey protein supplementation has been shown to increase the number of skeletal muscle satellite cells, which may lead to enhanced athletic performance. It also ​promotes muscle growth and improves recovery time​, making it ideal for athletes and gym-goers.


Furthermore, whey protein ​helps reduce body fat​ and preserves lean mass when combined with strength training. Another study, which appeared in Obesity Surgery in 2017, has found that whey may accelerate weight loss following bariatric surgery. ​Lactoferrin​ and ​lactalbumin​, two naturally occurring compounds in whey protein, appear to improve glycemic control, insulin sensitivity and metabolic health. These findings show that ​whey protein may benefit those with diabetes​ — and prevent people from developing this disease in the first place.


Read more:Can Diabetics Use Whey Protein Shakes?

Whey Protein Side Effects

This product is derived from milk, which contains ​lactose. Therefore, it's not the best choice for those who are lactose intolerant or allergic to milk. When consumed in appropriate doses, it's likely safe for healthy adults and children.

As WebMD points out, ​too much whey protein may cause digestive distress, fatigue, nausea and poor appetite​. Bloating, diarrhea and stomach cramps are common among those who consume whey in high doses. Whey protein side effects are largely caused by lactose.

According to the National Institutes of Health, about 65 percent of all people have lactose intolerance. This condition occurs when your body doesn't produce enough lactase, an enzyme that breaks down lactose. Researchers suggest that it may also have genetic causes, because it tends to run in families. However, some whey protein brands contain little or no lactose, so they're less likely to cause adverse reactions. You shouldn't consume whey protein if you have an allergy to milk.

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

Does Whey Affect Your Kidneys?

If you're drinking a protein shake twice a day or more, you may wonder how safe it really is. There are many rumors about protein powder side effects on the kidneys. The truth is that ​dietary protein doesn't affect renal function​. A 2014 study, published in the journal Nutrition, confirms that high protein intakes have no negative effects on kidney health in the elderly.

Excess protein, though, can be detrimental to those with chronic kidney disease, according to the journal Current Opinion in Clinical Nutrition and Metabolic Health. Researchers suggest that consuming too much protein may worsen this condition.

Tammy Sanders, RD, LDN, CDE, at DaVita®, a dialysis clinic chain, recommends that dialysis patients use one scoop of whey protein per day. They can add some to their morning coffee as well as to low-potassium fruit juices and homemade desserts. Depending on the brand, one scoop delivers about 10 to 50 grams of protein.

Read more:15 New Ways to Use Protein Powder That Will Blow Your Mind

Whey Protein and Liver Health

Contrary to popular belief, whey protein ​won't damage your liver​. You've probably heard of elite athletes who developed liver disease or died from cirrhosis. However, that's likely due to their use of ​anabolic steroids​, which causes hepatotoxicity.

Too much whey protein, though, ​can worsen existing liver diseases​, such as cirrhosis and hepatic encephalopathy. Dietary protein increases ammonia concentrations, which in turn, may affect hepatic function in people with liver problems. According to a 2014 study in Hepatology International, excess protein may worsen hepatic encephalopathy symptoms in up to 35 percent of cirrhotics. Furthermore, one-third of those who have this disease are protein intolerant.

If you have liver problems, consult your doctor before taking whey or other protein supplements. She is the only one who can determine whether these products are safe for you.


Unless directed otherwise by a doctor or dietitian, a high-protein diet is not recommended for people with existing liver or kidney problems as it may worsen their symptoms.

What About Weight Gain?

Whey protein and high-protein diets, in general, support weight loss and may improve body composition. They suppress appetite and keep you full longer, promote lean muscle growth and boost your metabolism. However, drinking too much protein can have the opposite effect.

Just like carbs, this nutrient provides ​4 calories per gram​. One scoop of whey protein isolate delivers about 16 grams of protein, 8 grams of carbs and 103 calories. Whey protein concentrate is higher in both carbs and protein, so it has more calories as well. Some brands contain 20 to 25 grams of protein per scoop.

If you drink three protein shakes per day, that's about 309 calories, 48 grams of protein and 24 grams of carbs at the least. It may not seem like much, but those shakes are not the only sources of calories in your diet. Therefore, the calories will add up, which ​may lead to weight gain​. If you've never used this supplement, start with one scoop and adjust your daily intake along the way.

How Much Is Too Much?

The recommended daily intake of protein — from both food and supplements — is ​0.8 gram per kilogram of body weight​ and 1.2 to 1.5 grams for people with disorders that may cause muscle wasting. Not everyone agrees with these guidelines, though. According to a 2016 review in the journal Food & Function, proper protein intake depends on your activity level. Researchers recommend:

  • 1.6 grams of protein per kilogram of body weight for high activity levels
  • 1.3 grams of protein per kilogram for moderate activity levels
  • 1 gram of protein per kilogram for minimal activity levels

The more active you are, the higher your protein requirements. If you consume too much protein, the excess is ​excreted in urine​ or ​converted to glucose​ and stored as glycogen and fat. Therefore, drinking several shakes a day won't speed up progress in the gym or help you lose weight faster unless you are highly active.

For best results, consume whey protein before and/or after training. This supplement ​digests quickly​, so it's ideal before exercise when your body needs a quick source of energy, as well as post-workout when it's used for muscle building and repair.