Plant-based farts

Have you ever found that some foods make you a bit (or a lot) gassier?

It’s no surprise that eating more plants (like vegetables) is good for your overall health including your heart, metabolism, and gut. But sometimes those health benefits can be a little . . . smelly.

Gut health (and flatulence) is due, in part, to our friendly gut microbes (our “microbiome”). This microbiome lives inside us and has been a hot topic for several years now. More and more research shows how important these health-promoting bacteria, viruses, etc. are for so many aspects of our physical and mental health even though they live in our gut.

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 are beneficial to our health. Yes, the fact that their metabolism helps us is what makes them “friendly” gut microbes.

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


What foods contain 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.

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 Western-type diet (high-fat, low fibre) versus a fibre-enriched (low-fat) 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 or farts. 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. 

How can you eat more plants and handle more farts/flatulence?

Eat more plants, just be prepared for better health and . . . more poop and farts. Of course, if you’re around others you can try to pass gas in a bathroom or outside whenever possible. If you don’t get the chance to discreetly slip away in time, then simply excusing yourself afterwards should do the trick.

Even in light of this flatulent finding, plants are oh so good for your health, so here are some of my favourite plant-based meals and resources:

  • For breakfast enjoy a fruit salad, smoothie, chia pudding, banana oatmeal, or whole-grain toast with avocado and sliced tomatoes
  • For lunch try a salad, add lots of veggies to your sandwich, and enjoy fruits, vegetables, and nuts as snacks
  • For dinner, fill half of your plate with vegetables, one-quarter with a whole grain like brown rice or quinoa, and the other quarter with your protein of choice.

Backgrounder article:

About the study:

  • This particular study is a small randomized controlled trial, so that’s pretty strong evidence especially applicable to the population of the participants: healthy men between 18 and 38 years old.
  • Note that all studies have limitations. That’s why it’s important to look at multiple studies, giving more weight to the ones that have a better design to answer the questions being asked.

Study strength is rated a 6/7 according to this chart: