How to Avoid the Smelly Side Effects of Eating Legumes!

brain health healthy eating healthy recipes real food resilience sugarfree Apr 18, 2022

Remember that nursery rhyme from many years ago?

“Beans, beans, The magical fruit,

The more you eat, The more you toot!

The more you toot, the better you feel

So let’s eat beans, With every meal!”

A couple of weeks ago, I was discussing food choices with a friend (it’s a favourite topic of mine!) and she was asking for some healthy snack ideas.  “Veggies and hummus!” I replied.  She hesitated, and then admitted that legumes like chickpeas make her … pass gas!

We all know that eating more plants (like vegetables) is good for your overall health including your heart, metabolism, and gut. But sometimes those health benefits can come with some less desirable side effects!

Gut health (and flatulence) is due, in part, to our friendly gut microbes (our “microbiome”). This microbiome lives inside us and is a topic I've written about before. More and more research shows how important these health-promoting bacteria, viruses, etc. are for so many aspects of our physical and mental health.

The health impacts of our gut microbiome come from the fact that—like us—they need to eat, digest, and metabolize nutritious foods, and excrete waste products so they can stay alive and prosper. This means these microbes eat some of what we eat and after they digest and metabolize it, their waste products, some of which are beneficial to our health, are left behind!  And the fact that their metabolism helps us is why we call them “friendly” gut microbes.

What causes the gas?

Beans (a type of legume) and other plants contain some sugars that we cannot digest. We are missing an enzyme that is required to break them down higher up in the digestive tract. When these undigested beans get to the colon, the bacteria in the colon begin to ferment the sugars and that’s what produces the gas.

So, what do our friendly gut microbes love to eat?   Fibre!

Plant-based foods like vegetables, fruits, nuts, seeds, legumes, and whole grains are ones we already know are very good for us. In addition to fibre, these plants also contain a lot of vitamins, minerals, essential fatty acids, and other health-promoting compounds. Some of the positive effects of plant-based foods are due to the nutrients they contain and other effects are due to how our gut microbes metabolize them.

Why else eat beans?

  • High in protein ― eating 1/2 cup (4 ounces) of cooked beans is equivalent to eating two ounces of lean protein.
  • Lots of fibre ― a 1/2 cup serving of cooked dry beans has 4 to 10 grams of fibre.
  • Rich in complex carbohydrates. Complex carbohydrates are known as “smart carbs.”
  • Rich in antioxidants.
  • Low in fat.
  • Have a low glycemic index.

And all of these features make them very healthy for your brain and body!


Recent Research

A recent study published in the journal Nutrients looked at how eating different diets can affect our friendly gut microbes. In this case, researchers looked at the impacts of a typical Western-type diet (high-fat, low fibre) versus a fibre-enriched Mediterranean diet.

While this study only looked at 18 healthy men 18-38 years old, the study methods were pretty strong. It was a randomized controlled trial. Randomization is when participants don’t choose how they participate in a study. In this case, they were randomly assigned to either the Western or Mediterranean diet for two weeks. During that time participants tracked a few different abdominal functions, one of which was their “anal gas evacuations,” otherwise known as flatulence. After those two weeks on their new diet, there was a two-week “washout period” where they ate a “standard” (moderate fat) diet to reacclimate their digestion and gut microbes. Then, for the final two weeks they “crossed over” into the other diet. This means that each participant did both diets for two weeks, so they served as their own “control.” One more strength of this study is that participants were given pre-portioned food, so this study didn’t ask them what they ate and rely on their memory, instead, it gave them what to eat and how much, so this improves the quality of the study.

The researchers found that when participants were eating the Mediterranean diet, they had “remarkably” more volume (more poop) and metabolic activity from their friendly gut microbes. They also experienced more flatulence with a larger volume of gas. 

The bottom line is that we already know that eating more plants is good for our digestive and overall health, this study uncovers a bit more about the reasons why. Plant-based foods with fibre feed our friendly gut microbes, resulting in them being happier and more metabolically active . . . and releasing more gas. 

Want to Reduce the Gas?  Some Tips for Prepping and Eating Beans

  1. Soak before cooking.  Studies have shown that soaking dried beans for 8-12 hours before cooking can help to reduce the quantity of indigestible sugars. If using canned beans, rinse them thoroughly.
  2. Eat lots of vegetables along with your beans, particularly green ones.
  3. Gradually add beans to your diet.  And start with mung or aduki beans as they are easy to digest because they are lower in the complex sugars that are not easily broken down by the human digestive enzymes.
  4. Chew and savour your food!  Beans are carbohydrates, so their digestion starts in the mouth. So savour them before swallowing to begin the process of digestion.
  5. In Japan and East Asia they eat seaweed (Kombu or Wakame) with the beans as it makes the beans more digestible, more nutritious and tastes great!
  6. Use digestive spices ― in India they cook beans with ginger, turmeric and sometimes fennel or asafetida to make them more digestible.

Even with the risk of flatulence, plants are oh so good for your health, not to mention very tasty (see the recipe below!), so it’s worth taking the time to let your digestive system get used to them!


Recipe:  Spicy Bean Salad


  • 1 cup Mung Beans, rinsed well (soaked if dry)
  • 1/4 - 1/2 cup Chickpeas, rinsed well (optional - start slowly)
  • 1/2 cup Aduki Beans, rinsed well 
  • 1 cup Green Beans, cooked and sliced into 1-inch pieces
  • 1 Red Onion, finely sliced
  • 1/2 Cucumber, thinly sliced
  • 1/4 Yellow Bell Pepper, chopped
  • Handful of Parsley, finely chopped
  • 2 teaspoons Extra Virgin Olive Oil 
  • 1 tablespoon Lemon juice
  • 1/2 teaspoon Turmeric powder
  • 3/4 teaspoon Cumin powder
  • 1/2 teaspoon Curry Powder
  • Sea Salt, to taste


  1. Prep and combine all the vegetables in a large bowl. 
  2. Combine olive oil, lemon juice and spices for the dressing, and pour over the vegetables.  
  3. Mix thoroughly and taste for seasonings. 
  4. Can be served immediately, or stored in the fridge for 1 - 2 days.


Barber, C., Mego, M., Sabater, C., Vallejo, F., Bendezu, R. A., Masihy, M., Guarner, F., Espín, J. C., Margolles, A., & Azpiroz, F. (2021). Differential Effects of Western and Mediterranean-Type Diets on Gut Microbiota: A Metagenomics and Metabolomics Approach. Nutrients, 13(8), 2638.

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