Constipation on a Vegan Diet: Common Causes and How to Relieve It
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Feeling Constipated on a Vegan Diet? Here’s How to Get Things Moving

Feeling Constipated on a Vegan Diet? Here’s How to Get Things Moving
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Updated on August 6, 2025
by
Beza Tekola, MD
If you’ve recently started eating a vegan diet, you’re not alone. About 1 percent of people in the United States identify as vegan, and some research shows veganism is on the rise domestically and worldwide.

Eating vegan (eliminating animal products, including meat, fish, eggs, and honey) may have its upsides, such as lower environmental impact, affordability, and certain health perks like weight management and improved digestion.

 But it may also have potential downsides, such as nutritional deficiencies or gastrointestinal concerns, if not properly managed.

Because switching to a vegan diet requires big shifts in previous eating patterns, it may affect your digestive system and possibly lead to constipation. Here’s why that happens and what you can do about it.

Dietary Fiber and Digestion

Adopting a vegan diet can alter your fiber intake, which may lead to noticeable changes in your poop.

Fiber is the part of a (typically plant-based) food that, for the most part, is not digested in the GI tract. The Academy of Nutrition and Dietetics recommends a minimum daily intake of fiber at 25 grams (g) for women and 38 g for men under the age of 50.

There are two main types of dietary fiber — soluble and insoluble — and they’re both important for digestion, but they don’t behave the same way in your body.

 Here’s how they differ:
  • ‌Soluble Fiber This type of fiber dissolves in water, so once in the GI tract, it soaks up water and turns into a gel. This slows digestion, making you feel full longer. Food sources include nuts, seeds, beans, lentils, peas, and some fruits and veggies.

  • ‌Insoluble Fiber This type of fiber does not dissolve in water, so it adds bulk to stool and appears to speed up the passage of foods through the stomach and intestines. It also helps to “sweep” the GI tract clean of carcinogens and other toxins. Food sources include wheat bran, vegetables, and whole grains.

Why Going Vegan May Lead to Constipation

Here’s a breakdown of two of the most likely reasons people might feel constipated after starting a vegan diet and how to remedy them.

1. You’re Getting Enough (or Too Much) Fiber and Not Enough Water

Healthy vegan diets tend to be higher in fiber. Indeed, one‌ systematic review analyzing 43 studies on dietary fiber intake found that vegan dieters consumed the most fiber — about 44 g per day — while vegetarians consumed 38 g per day, and omnivores consumed 21 g. Authors also found that vegans met the adequate intake of dietary fiber, whereas only women vegetarians met it, and meat-eaters did not.

Getting enough fiber is crucial for keeping you regular, but it only works if you’re also getting enough water.

 Why? Staying hydrated makes stools softer and easier to pass, and pairing a fibrous diet with plenty of water and frequent exercise can promote healthy bowel movements.

 In other words, skimping on water intake with a high-fiber diet may lead to feeling constipated.
The Fix: To prevent this, ensure you’re getting enough fluids. As a rule of thumb, this is about eight 8-ounce (oz) glasses of water per day, according to the Cleveland Clinic.

More specifically, the National Academy of Sciences recommends women consume 2.7 liters (L) — that’s nearly 11.5 cups — of total water per day and men drink 3.7 liters per day, or about 15.5 cups. This includes food, beverages, and drinking water.

Note that these are general guidelines, and hydration requirements differ by individual needs. Various factors like exercise, illness, and environment can also affect how hydrated you are. Be sure to speak to your doctor or a registered dietitian if you are considering starting a vegan diet or if you already eat vegan for guidance on how much water you need per day.

2. You’re Not Eating Enough Fiber

While vegan diets tend to be higher in fiber, there’s a catch: Over the past few years the availability of plant-based food options (meat alternatives, frozen dinners, yogurts, cheeses, jerky, and more) have increased in supermarkets. Sales in this category topped $5 billion in 2019.

This innovation and growth offers options and flexibility for vegans, vegetarians, and plant-based eaters, but these new foods may not be the healthiest. Many are highly processed, which means they typically don’t offer the same level of nutrition as whole foods do, and it’s important to keep in mind that much of the research done on the benefits of a vegan diet has been based on whole foods.

These newer plant-based products may decrease the amount of fiber (and other nutrients) you’re consuming for two reasons:

  • They lack fiber themselves
  • They’re replacing fiber-filled foods from your diet

‌The Fix:‌ If you’re new to a vegan diet or eat vegan and incorporate these more processed plant-based foods, keep track of how much fiber you’re consuming, and aim to eat mostly whole foods most of the time.

If you’re drinking the recommended amount of water and eating enough fiber, but you’re still constipated, speak with your doctor. This is especially important if constipation lasts more than three weeks or if you experience additional symptoms like blood in your poop, unintentional weight loss, or severe pain with bowel movements.

The Takeaway

  • Eating vegan offers potential benefits like improved digestion, weight management, and a lower environmental impact.
  • Switching to a vegan diet can come with a big increase in fiber intake, which supports digestion but requires enough water to avoid constipation.
  • Constipation may occur if you don’t drink enough fluids or if you rely too heavily on processed vegan foods, which might have lower fiber contents, instead of whole, fiber-rich foods.
  • If you’ve started a vegan diet and constipation lasts more than a few weeks or is accompanied by pain, blood, or weight loss, it’s important to see a doctor to rule out other health issues.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Jones JM. In U.S., 4% Identify as Vegetarian, 1% as Vegan. Gallup. August 24, 2023.
  2. Bali A et al. The Impact of a Vegan Diet on Many Aspects of Health: The Overlooked Side of Veganism. Cureus. February 18, 2023.
  3. Viroli G et al. Exploring Benefits and Barriers of Plant-Based Diets: Health, Environmental Impact, Food Accessibility and Acceptability. Nutrients. November 8, 2023.
  4. Is a Vegan Diet Healthy? Cleveland Clinic. July 3, 2024.
  5. Ellis E. Dietary Fiber. Academy of Nutrition and Dietetics. November 3, 2020.
  6. Higdon J et al. Fiber. Oregon State University Linus Pauling Institute. March 2019.
  7. Neufingerl N et al. Nutrient Intake and Status in Adults Consuming Plant-Based Diets Compared to Meat-Eaters: A Systematic Review. Nutrients. December 23, 2021.
  8. Why Is Fiber So Important? Cleveland Clinic. May 1, 2025.
  9. Constipation. Cleveland Clinic. July 18, 2023.
  10. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. National Academy of Sciences. 2005.
  11. Gaan K. Plant-Based Food Retail Sales Hit $5 Billion. Good Food Institute. March 3, 2020.
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Beza Tekola, MD

Medical Reviewer

Kelly Plowe, MS, RD

Author

Kelly Plowe is a registered dietitian and nutrition communications expert. She has carved a unique career path by blending her expertise in nutrition with her love for communication across diverse sectors, including consumer product goods, food service, health tech, and media.

Kelly holds a bachelor’s degree in dietetics and kinesiology from Michigan State University and a master's degree in advertising from Boston University. She has written for EatingWell, Headspace, Livestrong.com, Verywell Fit, Aramark, and Beachbody.

As a dietitian, she plays a pivotal role in guiding individuals toward healthier lifestyles. Her expertise, honed over years of experience, and her educational background underscore her unique ability to bridge the gap between science and storytelling. Her work has been at the intersection of informing and inspiring, where she has helped people make healthier choices through compelling content and messaging.

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