Onions: ubiquitous in almost all cuisines as an essential base upon which to build flavors. They're tasty, and bring so much to a dish...including for many, gas and gastrointestinal discomfort. So, do onions make you fart?
First of all, I want to specify that there is no way I can diagnose the exact reason for your gassiness from an article. That'd be impossible. To do that I'd need to meet you, ask a lot of specific questions, and smell all of your stinky farts (kidding on that last one).
What I can offer, however, is some compelling information on the scientific make-up of onions, and potential implications for certain people.
Onions are super high in FODMAPs. FODMAP is short for fermentable oli-, di-, mono-saccharides, and polyols. Basically, FODMAPs are sugars your body has a hard time breaking down, and they're notoriously super-fermentable and highly osmotic.
This means the bacteria in your gut flock to the FODMAP sugars and try their best to break them down. And this process can lead to a lot of gas and bloating.
FODMAPs also attract lots of water to the intestines, so FODMAPs often bring on diarrhea. If you want to learn more about FODMAPs and which foods are higher and lower in them, check out this legit resource from Standford University.
Seeing as onions are one of the highest FODMAP offenders, it is highly plausible that they can lead to stinky, smelly farts.
If you suspect onions make you fart, I would suggest reducing the amount of onions, and FODMAPs in general, that you eat in one sitting (think smaller portions of these foods, or try to space them out throughout your day).
Garlic is also full of FODMAPs (sad, I know), so try adding flavor to dishes with fresh or dried herbs, spices, or flavored oils. This article will give you an even clearer understanding of foods to eat and avoid when your intestines are acting up.
Otherwise, enjoy your onions, and your farts too.