If you’ve recently started following a vegan diet, an unexpected (and frustrating) increase in bloating and gas may have tempered your initial excitement. Why would such a nutrient-dense diet cause such annoying symptoms, and is there anything you can do to stop it?
As a vegan dietitian, I’ll discuss the potential causes of vegan diet-related bloating and provide practical tips for easing it.
What is bloating?
Bloating is defined as a swollen feeling or feeling of fullness caused by fluid or gas retention. It may or may not be accompanied by abdominal distention, which is the visible increase in the size of the abdomen.
Why you might be feeling bloated on a vegan diet
If you’re new to the vegan lifestyle, there are a few reasons why you might be feeling gassier than usual.
High fiber intake
One of the most significant benefits of 100% plant-based diets is the plethora of fiber-rich foods you can enjoy.
While most Americans struggle to get the daily recommended amount of fiber, vegans often have no trouble getting enough as long as they eat a variety of whole and minimally processed fruits, vegetables, beans, nuts, and whole grains.
Fiber is great for improving gut health, supporting a healthy immune system, and fighting inflammation, but too much of a good thing can be difficult for the gut to manage at first.
Some gas and bloating with fiber intake is normal, but the digestive system will take a while to adjust if it isn’t used to large amounts of fiber. If you’ve switched to a whole food plant-based diet after eating a relatively low-fiber diet, you’ve probably noticed a significant increase in bloating or flatulence.
Another factor is the increased volume of plant-based meals. Meals based on whole plant foods tend to be lower in calories, so many people end up eating larger volumes of food to get enough calories and stay satisfied throughout the day. Larger meals, especially when high in fiber, can take longer for the body to digest.
The longer food sits in the digestive tract, the more opportunity there is for gas production.
FODMAPs
Plant-based diets tend to be high in a variety of compounds grouped under the term “FODMAPs”, which stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.
These short-chain carbohydrates can cause symptoms of bloating and abdominal pain in people with Irritable Bowel Syndrome (IBS). Some people may be sensitive to one or more of these compounds.
A low-FODMAP diet is often recommended and effective for helping people identify their trigger foods so that they can avoid them and ease uncomfortable IBS symptoms. It’s important to work with a registered dietitian trained in FODMAP elimination diets to make sure you aren’t unnecessarily restricting foods you aren’t sensitive to, however.
People without IBS usually have no issues with tolerating FODMAPs.
Not chewing thoroughly
Eating too quickly can be another cause of bloating. When you don’t chew your food thoroughly, your digestive enzymes may not be able to reach as much of it. This can lengthen the time needed for digestion.
If you tend to eat quickly, try taking a moment to center yourself before you begin eating. Avoid eating while scrolling on your phone or watching a show, as these can be distracting. If you’re ravenous at mealtimes because you’ve gone too long without eating, try having a small snack on hand to help manage your hunger levels.
Other causes of bloating & gas
When trying to determine if it’s your vegan diet that’s truly causing bloating, it’s important to be aware of other factors that may play a role.
- Constipation. Constipation is less likely on a plant-based diet thanks to the high fiber content, but it can still occur as a side effect of certain medications or inadequate water intake.
- Small intestinal bacterial overgrowth (SIBO). This is a medical condition where the number of gut bacteria in the small intestine is much higher than normal. In healthy people, most gut bacteria are located in the large intestine. With SIBO, an excessive amount of these bacteria spill into the small intestine. SIBO requires medical treatment to resolve.
- Gastroparesis. This medical condition slows the digestive tract and significantly increases the amount of time it takes to digest and absorb a meal. Bloating is common, especially when eating high-fat or high-fiber meals.
- Antibiotic therapy. Antibiotics are live-saving medications that unfortunately kill off the good bacteria in your gut in addition to pathogenic bacteria. Being on antibiotics long-term can throw off the balance of your gut microbiome and lead to bloating, gas, and abdominal distention.
- Celiac disease. This is an autoimmune condition where the immune system treats gluten, the protein found in wheat, as an invader. With this condition, gluten physically damages the lining of the intestines. People with Celiac disease who don’t avoid gluten experience significant gastrointestinal symptoms as a result, which can include bloating and gas.
How to reduce gas & bloating on a vegan diet
It’s important to remember that some level of gas and bloating is normal on a vegan diet thanks to the many prebiotic foods included in this dietary pattern.
Plant-based foods are rich in fiber, polyphenols, and other prebiotics which fuel the growth of beneficial, anti-inflammatory bacteria in the gut, keeping these bacteria healthy and active. Our gut bacteria ferment dietary fiber and provide us with a number of health benefits, but a side effect of this is the production of gas.
Gas production is especially noticeable when beginning a plant-based diet or incorporating more whole, fiber-rich foods at meals. It can take a while for your digestive system to adjust.
Fortunately, there are some strategies to help prevent excessive gas production.
1. Increase fiber intake gradually
Switching from a standard Western diet or vegan diet high in processed foods to a vegan diet high in whole, high-fiber foods overnight can overwhelm your digestive tract and lead to excessive gas and bloating. This isn’t dangerous, just inconvenient and uncomfortable.
Try the following tips for increasing your fiber intake gradually:
- Alternate between refined grains and whole grains. For example, you may want to alternate between white and brown rice with curries. You could also have whole-grain oatmeal at breakfast, white pasta at lunch, and a mix of brown and white rice at dinner.
- Focus on easier-digesting proteins. Tofu is relatively low in fiber and is easier to digest than whole beans like black beans, chickpeas, and kidney beans. Red lentils are often easier to digest as well since they become very soft when cooked. Another option is seitan, made primarily from vital wheat gluten and either tofu, pea protein powder, or chickpeas. Seitan is lower in fiber since it isn’t made from whole beans, and tempeh is generally well-tolerated thanks to being a fermented food.
- Soak and rinse your beans. Soaking dried beans overnight can help remove excess raffinose, a natural sugar that is particularly associated with gas production. If using canned beans, rinse them well under plenty of cool water.
- Cook your vegetables. Cooking softens the fiber present in raw vegetables and makes it easier for the body to digest. Try alternating raw salads with cooked vegetables at mealtimes. A side of roasted vegetables, vegetables simmered in soup or curries, and sauteed greens are all excellent options.
- Eat some blended foods. Like cooking, blending softens and breaks down some of the dietary fiber in plant-based foods. Blended soups, hummus, vegan refried beans, creamy dal, and white bean dips can all help.
2. Hydrate
Water is required in order to properly digest our food, including fiber, so staying hydrated can help prevent symptoms of bloating. Soluble fiber, in particular, attracts water. If there isn’t enough water present in the surrounding tissues to pull into the intestines, constipation and bloating can occur.
Spreading your water intake throughout the day, not just at mealtimes, will help ensure an adequate supply of water to assist with digestion as your body needs it. Shoot for about 8 cups of water a day.
3. Sip on peppermint tea
Peppermint oil can relax the digestive tract1 and may help ease bloating. Peppermint tea naturally contains peppermint oil, a known antispasmodic, so feel free to try this calming herbal tea in combination with the other strategies on this list.
4. Consider a digestive enzyme supplement
If you’ve increased your fiber intake gradually, are drinking enough water, and have given your gut a few months to adjust, a digestive enzyme supplement may help. Most commercially available digestive enzyme supplements contain a variety of enzymes, most of which have no proven benefit for healthy people.
However, alpha-galactosidase is one enzyme that some vegans find helpful. This enzyme helps digest dietary fiber in the foods we eat. Humans don’t naturally produce this enzyme and can’t digest fiber ourselves, which is where our gut bacteria come in. However, the extra assistance from supplemental enzymes is sometimes needed.
Unfortunately, the most well-known brand of alpha-galactosidase, Beano, may not be vegan. It no longer contains gelatin but does contain magnesium stearate, which is often sourced from animals. Fortunately, vegan versions such as Bean-Zyme are available.
Summary
It’s normal to experience an increase in gas and bloating when switching to a vegan or plant-based diet, but these symptoms are usually a good sign that you’re fueling the beneficial bacteria that live in your gut.
Fortunately, there are some ways to ease these symptoms as your gut adjusts to a higher-fiber diet.
Increasing fiber gradually, drinking enough water, seeking medical treatment for underlying health concerns, and considering digestive enzymes if needed are all strategies that can help you feel your best while reaping the health benefits of a vegan diet.
The scientific information in this article was accurate at the time of publishing but may change over time as new research becomes available.
References
- Alammar N, Wang L, Saberi B, et al. The impact of peppermint oil on the irritable bowel syndrome: a meta-analysis of the pooled clinical data. BMC Complement Altern Med. 2019;19(1):21. Published 2019 Jan 17. doi:10.1186/s12906-018-2409-0
