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Can Too Much Protein Cause Constipation? (From a Dietitian)

Isaac Robertson
Published by Isaac Robertson | Co-Founder & Chief Editor
Last updated: August 18, 2023
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A high-protein diet is great for keeping you in shape, but if you feel stuffed up lately, chances are you’re eating too much protein.

Excess protein may cause digestive issues, including constipation, and may have other adverse effects, too.

So, through in-depth research, let us find out whether high-protein consumption causes constipation and how you can avoid it.

Quick Summary

  • Consuming too much protein and less fiber in your diet can result in constipation.
  • To avoid constipation while consuming a high-protein diet, include non-starchy vegetables like spinach, and cabbage.
  • Remedies for constipation are drinking more water, working out, and increasing your fiber intake.

Does a High-Protein Diet Cause Constipation?

man seated down holding his bellyache

Yes, but it is not the protein but the lack of fiber in your diet that is directly causing it.

A high-protein diet or low-carb diets such as the Atkins diet or keto diet are focused on eating animal proteins.

Unfortunately, animal proteins such as eggs, fish, and red meat do not have fiber at all.

Fiber is a form of carbohydrate that our bodies can’t digest. Instead, insoluble fiber absorbs water and passes through the GI tract (Gastrointestinal tract) smoothly.

Then, it sweeps through our bowels, carrying everything out. It also adds weight and softens our stool to push it easily out of our bodies.

“Fiber helps stabilize transit time – how fast the food moves through the digestive tract.”

– Dr. Joanne L. Slavin, Professor of Food Science & Nutrition at the University of Minnesota

So, lack of fiber causes slow bowel movement, often resulting in hard stools, thus causing constipation.

Ways To Avoid Protein-Related Constipation

bowl of kale, and a plate filled with spinach

If you’re currently on a high-protein diet and want to prevent constipation, your best bet is to keep your meals balanced.

  • Include non-starchy vegetables such as dark leafy greens vegetables: kale, spinach, Asian greens, cabbage. They are low in carbs and high in fiber.
  • Balance your animal protein intake with plant-based proteins such as lentils, peanuts, kidney beans, and almonds.
  • Check the protein shakes you consume. Although they normally don’t cause constipation, consuming large amounts or components such as lactose or gluten may cause digestive issues.
  • Drink more fluids.

Remedies for Constipation

woman chugging a drink of water, man warming up in a field

Constipation may cause fatigue over time so, here are things you can do when you are constipated.

1. Increase your fiber intake

Enough fiber is the key to healthy bowel movements. So, make sure you eat more fiber in your diet, especially insoluble fiber found in wholegrain foods, root vegetables, beans, pulses, and lentils (also high in soluble fiber).

2. Drink more water

Increasing your water intake helps soften stool and move it easily through the GI tract, relieving constipation. Carrying around a water bottle ensures you drink plenty of it!

3. Exercise

Doing a digestion-friendly exercise such as a 15-minute walk or jog an hour after you had your meal, helps relieve constipation because it improves your blood flow.

Related: Yoga Poses for Constipation

4. Eat probiotic foods

Probiotic foods contain “good” bacteria that are safe and help improve bowel movements and soften hard stools.

What's a Normal Protein Intake?

glass and pitcher of milk, and a tray filled with food filled with protein

The right amount of protein to take depends on several factors such as your age, gender, activity, health, and total diet.

However, it is usually determined by your body weight.

The recommended dietary allowance (RDA) is 0.36 grams of protein per pound (0.8 grams per kg) of your body mass [1].

It’s about 56 grams per day for an average man with an inactive lifestyle (not exercising) and an estimated 46 grams per day for an average woman with an inactive lifestyle.

Those who have an active lifestyle, eating 1.2 to 1.7 grams per kg of body weight each day do them well.

Elite athletes need to consume more protein for weight loss and improved athletic performance. The International Journal of Sports Nutrition recommends 1.6 to 2.4 grams of protein per kg body weight per day.

Unsure about the right amount of protein for your needs? Ask a dietitian or a nutritionist to get more specific numbers to achieve the best results.

If you are looking to add a protein supplement to your diet, make sure you check out our article on the best whey protein powders on the market.

What Are the Side Effects of Too Much Protein?

man showing off his belly fats while squeezing it, woman smelling her breath with her hands

High dietary protein intake may be the cause of constipation and other negative effects on human health, such as diarrhea, gaining weight, dehydration, etc.

  • Diarrhea - Eating too much dairy products and processed food plus lack of fiber may cause diarrhea.  Avoid diarrhea: limit fried foods, avoid caffeinated beverages, increase your fiber intake, and reduce excess fat consumption.
  • Weight Gain - Eating fewer carbs and consuming more protein help you lose weight and  grow muscles. However, it may lead to excess calories that are stored as fat, resulting in an increased body weight.
  • Dehydration - High protein diets cause your kidneys to work overtime to flush out excess nitrogen found in the protein’s amino acids out of your system. As a result, you urinate a lot, feel more thirsty than usual, and worse, wreck your kidneys over time.
  • Calcium loss - Some protein sources are high in acid that binds with calcium and is excreted in the urine, resulting in loss of calcium. It is said to cause bone issues over time; however, no research proves it yet.
  • Heart Disease - Increased protein intake from red meat and full-fat dairy foods increases risks of heart disease because they contain high saturated fat that can build up around the blood vessels. It is best to eat heart-healthy meals.
  • Risk of cancer - Eating protein in large quantities, especially those coming from red and processed meat is linked to increased cancer risk. It is because these high-protein foods are considered carcinogenic.
  • Bad breath - As our bodies break down protein’s amino acids, it releases ammonia that produces a strong odor on our breath; so, extra protein may lead to bad breath.

Related Articles:

Keep Your High-Protein Diets Balanced

Protein is our body’s building blocks that helps muscle gain and repair muscle fibers.

However, too much protein and less fiber cause constipation and health problems, so make sure you eat protein right and maintain a healthy diet.

It means eating lean protein, whole grains, enough carbs, and a lot more fiber from fruit and vegetables and drinking plenty of water. If you adopt healthy habits, your overall health will improve.

Don’t forget to share your experience in the comment section.


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