How to Ease Low-Carb Constipation

Whenever you make changes to the way you eat, you can expect to experience some changes in digestion. Many people on low-carb diets experience constipation when they first make the change, but it usually gets better with time.

However, constipation can be caused by factors other than your diet. Certain medications and some health conditions can also be the culprit. While dietary changes are a common cause of bowel changes, if constipation persists, talk to your doctor.

If you’ve recently started a low-carb eating plan and are experiencing “keto constipation,” there are several ways you can ease the symptoms and help your body adjust.

What Is Constipation?

Constipation is generally described as having fewer than three bowel movements per week—however, what’s considered “normal” varies widely from person to person.

If you usually have a bowel movement each day and suddenly you don’t pass stool for several days, you’re straining to have a bowel movement, and/or you’re experiencing abdominal pain and bloated, you’re likely constipated.

Constipation happens for a number of reasons. If you get dehydrated, your stool can get dried out, making it harder to pass. In some cases, the hard, dry, stool can get stuck and lead to a fecal impaction.

Sometimes, constipation is caused by problems with the intestines rather than the stool. Medications, health conditions, your level of physical activity, and even stress can make the bowel work more slowly, which means stool will take longer to move through the intestines.

If you’ve recently had surgery, general anesthesia also causes nerve signals to your bowel to slow down, though the effect is temporary.

Conditions that affect your nervous system, like multiple sclerosis and Parkinson’s disease, can also cause constipation.

In some cases, there may be problems in the last part of the bowel or near the opening of the rectum that prevents stool from passing normally. Hemorrhoids, anal fissures, and rectal prolapse are common conditions that get worse when you strain to have a bowel movement.

Serious health problems like anal cancer or complications from inflammatory bowel disease can also cause bowel changes. However, these conditions usually have other signs and symptoms, like rectal bleeding, fever, and weight loss.

Low-Carb and Keto Constipation 

Any change to your diet can lead to changes in your bowel habits, especially when you first get started. In studies on children with epilepsy being treated with the Keto diet, constipation is a well-known side effect.

While it generally doesn’t last long and can be treated, some people find the side effect of continued constipation to be troubling enough that they give up on a low-carb diet.

One reason people on low-carb and Keto diets experience constipation is that they’re usually eating less fiber (soluble fiber, insoluble fiber, or both). Reduced fiber intake is especially common when people are unsure about what can be included on a low-carb diet.

Foods that are high-fiber and nutritious, but low in digestible carbohydrates, are a staple of a well-rounded low-carb diet.

For example, you might eat fewer starchy vegetables but not realize you should increase the number of non-starchy vegetables you eat.

While fiber is a carbohydrate, most low-carb diets don’t factor it in as part of your daily carb allowance, since it doesn’t have an impact on your blood sugar.

Even if you understand your diet plan and goals, eating low-carb or according to the Keto diet may still cause constipation. If it happens to you, use these tips and tricks to ease your symptoms until your body adjusts to the change.

Stay Hydrated

Drinking enough water each day is important to your overall health, but proper hydration is especially important for regular bowel function. When you aren’t drinking enough water, your body begins pulling water from your colon to combat dehydration.

When the water leaves your intestines, it’s no longer there to help hydrate stool and lubricate it as it passes through, which can lead to constipation.

Not all fluids are created equal when it comes to staying hydrated. Avoid excess alcohol and caffeinated beverages, which can be constipating. If you struggle with gas and bloating, avoid carbonated, sparkling, or seltzer drinks.

Eat Non-Starchy Vegetables

Even though they do have carb counts, some low-carb diets don’t count low-carb vegetables, like leafy greens.

Non-starchy vegetables are high in fiber, have lots of nutrition, and are very low in digestible carbohydrates. These qualities mean they have little to no impact on your blood sugar levels, making them a good low-carb choice compared to starchy vegetables.

You can also increase the gut health benefits by lightly salting your veggies. On a low-carb diet, especially one where you've committed to reducing or cutting out processed foods, the sodium balance in your body will change. The altered fluid balance can contribute to constipation.

While you don't want to consume high amounts of salt, you do need to get adequate amounts in your diet. It's easy to make sure you're getting a healthy amount—simply salt your food to taste or add a pinch while cooking.

Add Natural Laxative Foods

Many foods have a natural laxative effect. Foods that are full of fiber and omega-3 fatty acids promote regular healthy bowel function.

Some of the most popular options include:

If you're on a low-carb diet you'll want to avoid high-sugar fruit. Instead, opt for low-sugar fruit like berries and citrus fruit, which can be a great source of fiber.

With lots of essential vitamins and minerals, as well as fiber, in a tiny package, nuts and seeds are a quick, easy, way to combat constipation.

Flax and chia are among the most versatile and nutritious options. With more soluble fiber than other varieties, flax and chia seeds are popular natural dietary remedies for constipation.

You can easily add many of these foods to your morning yogurt (which is also full of good-for-gut probiotics) or use them as ingredients for a fiber-fueled smoothie.

Many great sources of fiber are acceptable on a low-carb diet, but that doesn't mean you want to overdo it. Overeating—even healthy foods, and particularly those that have lots of fiber—can lead to digestive discomfort.

Try Fiber Supplements

While you should focus on getting as much dietary fiber from food sources as possible, fiber supplements can also be helpful if you’re struggling with constipation.

The most common ones (e.g. Metamucil and Fiberall) are made from psyllium husks. Psyllium is mostly soluble fiber but has some insoluble fiber as well. Once the powder has been mixed with water, you need to drink it fairly quickly—otherwise, it can get sludgy and thick as the fiber absorbs fluid.

If you’re on a low-carb or Keto diet, however, these options may present a problem: These products, which come as a powder you mix into water or your morning coffee, contain a fair amount of sugar.

There are "sugar-free" versions, but they contain ​maltodextrin— a sugar substitute that raises blood glucose just as much as sugar does.

You can also take psyllium capsules, though you need to take more of them to equal the effect of the powder—be sure you take them with plenty of water.

An alternative to powders or capsules is purchasing whole psyllium husks at your local health food store.

Benefiber is another popular fiber supplement. It’s entirely soluble fiber, unlike psyllium, so it dissolves it in water or mixes into soft foods like yogurt without changing the texture.

Other fiber supplements are primarily insoluble fiber. One example is wheat bran. While it can be an effective dietary remedy for constipation, it can be high in carbs. If you’re on a low-carb diet, watch the starch content of bran cereals.

Don't Overdo Dairy

When you’re reducing carbs, you might find yourself adding more dairy products to your diet, especially cottage cheese and yogurt.

While milk is often associated with the gastrointestinal symptoms of lactose intolerance, some people actually find milk products constipating.

If you’ve recently started eating low-carb and have added more cheese, milk, and yogurt to your diet, try cutting back and see if your symptoms improve.

You can also try switching milk for non-dairy alternatives like rice, almond, and soy milk.

Mind Your Magnesium

If you’re low in magnesium, one common side effect of magnesium deficiency is constipation.

While you want to avoid nutrient deficiencies, whenever you eliminate certain food groups from your diet or reduce your intake, you do run the risk of not getting enough of certain vitamin and minerals. Luckily, it’s easy to find other sources of these key nutrients that won’t have a negative impact on your diet.

Many low-carb foods, like green leafy vegetables, nuts and seeds, soy, legumes, fish, and yogurt are good sources of magnesium.

If you’re deficient in magnesium and not able to replace it adequately through food, consider taking a supplement. However, some forms of magnesium are absorbed better than others.

If you are taking a form your body doesn’t absorb well, you could find yourself going from one end of the bowel spectrum to the other, as these supplements can cause diarrhea.

Give Probiotics a Go

The research on probiotics is far from conclusive, but some preliminary studies indicate certain foods, such as yogurt and kefir, may have an impact on the bacterial colonies (or microflora) of our colons.

In some cases, having the right kind of bacteria (and in the right amounts) may help with certain bowel symptoms.

While the research on gut health is still evolving, there are many ways to try probiotics and see if they benefit you. Aside from dietary sources, there are also probiotic capsules, gummies, and even drinks.

Use Fish Oil

Some research suggests that inadequate amounts of omega-3 fatty acids in our diets can contribute to constipation. Fish like salmon are rich dietary sources of omega-3s that work well on a low-carb diet.

If you don’t eat a lot of oily fish, you can also try adding a fish oil supplement, though they can have side effects.

People taking fish oil supplements sometimes experience:

  • Nausea
  • Heartburn
  • Diarrhea
  • Abdominal pain
  • A fishy aftertaste in the mouth, especially when burping

If you try fish oil supplements and find these side effects troubling, talk to your doctor about ways to lessen them or consider trying to get more omega-3s from dietary sources instead.

Move Your Body

Getting regular exercise, even something as simple as a lunchtime stroll or taking the dog for a walk after dinner, can help address several potential causes of constipation.

Increased activity encourages your bowels to get moving. Exercise can also help reduce stress, anxiety, and tension which can all contribute to constipation.

Should You Use Laxatives?

Unless your doctor advises you to, avoid stimulant and herbal laxatives or enemas until you’ve tried other methods to treat constipation. Stimulant laxatives, enemas, and herbal remedies like Senna, come with their own side effects and risks—and they may not provide long-term relief.

Other over-the-counter products like stool softeners can help ease the symptoms of constipation without the stimulant effect. These products can be helpful if your constipation is caused by hard, dry, stool, but may not work for other causes.

If you are sure a dietary change is causing constipation but these tips don't ease your symptoms, be sure to talk to your doctor. Constipation can be caused by a number of health conditions and knowing the reason you're experiencing it will help you find the right treatment.

Was this page helpful?

Article Sources

  1. Bazzano LA, Hu T, Reynolds K, et al. Effects of low-carbohydrate and low-fat diets: a randomized trialAnn Intern Med. 2014;161(5):309–318. doi:10.7326/M14-0180

  2. Liu LW. Chronic constipation: current treatment optionsCan J Gastroenterol. 2011;25 Suppl B(Suppl B):22B–28B.

  3. Araghizadeh F. Fecal impactionClin Colon Rectal Surg. 2005;18(2):116–119. doi:10.1055/s-2005-870893

  4. Andrews CN, Storr M. The pathophysiology of chronic constipationCan J Gastroenterol. 2011;25 Suppl B(Suppl B):16B–21B.

  5. Andresen V, Whorwell P, Fortea J, Auzière S. An exploration of the barriers to the confident diagnosis of irritable bowel syndrome: A survey among general practitioners, gastroenterologists and experts in five European countriesUnited European Gastroenterol J. 2015;3(1):39–52. doi:10.1177/2050640614558344

  6. Wibisono C, Rowe N, Beavis E, et al. Ten-year single-center experience of the ketogenic diet: factors influencing efficacy, tolerability, and compliance. J Pediatr. 2015;166(4):1030-6.e1. doi:10.1016/j.jpeds.2014.12.018

  7. Oh R, Uppaluri KR. Low Carbohydrate Diet. In: StatPearls. Updated May 13, 2019.

  8. Masood W, Uppaluri KR. Ketogenic Diet. StatPearls. Updated March 21, 2019.

  9. Cozma-Petruţ A, Loghin F, Miere D, Dumitraşcu DL. Diet in irritable bowel syndrome: What to recommend, not what to forbid to patients!World J Gastroenterol. 2017;23(21):3771–3783. doi:10.3748/wjg.v23.i21.3771

  10. Reis DJ, Ilardi SS, Punt SEW. The anxiolytic effect of probiotics: A systematic review and meta-analysis of the clinical and preclinical literaturePLoS One. 2018;13(6):e0199041. doi:10.1371/journal.pone.0199041

Additional Reading