>Here I feel the need for an aside. Many, many people will tell you that the key to reducing bean gas is to eat more beans. Eating more beans, they argue, works because it allows our digestive systems, and the microbiome in them, to acclimate to the beans. Over time, they say, the gassiness will go down. This makes no sense to me. If these oligosaccharides are food for bacteria in our gut, common sense would say that feeding that bacteria more food would, if anything, do the opposite by supporting their population growth while giving them plenty of raw material to digest. It wasn't within the scope of this project to test (and, I suspect, disprove) this theory, but count me as highly doubtful. If anything, I have to imagine that eating more beans more often just makes people more used to being gassy, and that, in turn, makes them notice it less. (Their significant others might have a very different take…)

I agree with this in principle but have to point out a few flaws in practice.

First, the immediate product of fermentation is not methane, despite what your high school biology teacher told you. It's hydrogen. In fact, bacteria do not produce methane at all! Only archaea are capable of methanogenesis. This is a rather surprising fact nobody mentioned in school:

https://en.wikipedia.org/wiki/Methanogenesis

>Organisms capable of producing methane for energy conservation have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria.

So there is some room for error here. When methanogenesis occurs, the volume of gas is reduced by 80%:

4 H2 + CO2 >> CH4 + 2 H2O (l)

But I have never seen any evidence that the amount of archaea or the extent of methanogenesis in the digestive tract varies with diet. However, it does change under certain circumstances, and more methane in enteric gas is generally correlated with less hydrogen:

https://www.jstage.jst.go.jp/article/bmfh/45/1/45_2025-044/_...

>However, methane gas production was not changed by dietary intake, suggesting that intervention with prebiotics may be necessary.

https://iopscience.iop.org/article/10.1088/1752-7155/7/2/024...

>Usually patients produce either hydrogen or methane, and only rarely there are significant co-producers, as typically the methane is produced at the expense of hydrogen by microbial conversion of carbon dioxide. Various studies show that methanogens occur in about a third of all adult humans

(The second study is less optimistic than I am about methanogens reducing intestinal discomfort.)

But there is another thing that can change the amount of noticeable farting: unnoticeable farting. The digestive tract has its own nervous subsystem which reacts to stimuli and processes information. It's plausible that if you produce a lot of gas for a long time, your digestive tract learns to let it out gently. This may reduce irritation of the epithelium.