Urban humans have lost much of their ability to digest plants (opens in new tab)

Ha, seems like what all those kooky carnivore diet proponents have been saying all along... (disclosure: am on carnivore diet). Yeah, I personally believe the microbiome plays a big part, I know for sure mine was messed up growing up and increasingly so, after rounds of antibiotics, sugary foods, etc. etc.

But I've also come to the conclusion humans are facultative carnivores, that plants have always been a fallback food.

Maybe this explains why every lunch at Pura Vida makes me feel bloated these days... maybe I should just keep at it and this (gas) too shall pass

It'd be interesting to see more data that could help narrow down potential factors in the difference of gut microbes.

Highly processed foods and use of prescription drugs (especially antibiotics) come to mind. I could see both of those being different for rural vs urban populations and would likely have some impact on microbiomes.

When you inoculate cattle rumen normally the shared water trough keeps it going. So you might inoculate some cattle then the rest will also get inoculated. It might even be tied individual cows losing the inoculation, the herd can keep it going.

Similarly having camels with cattle does this, since camels naturally have gut bacteria of value they pass it on through shared water.

Once thing I noticed going from sharing a beer with our goats to soft drink, beer being a brown bottle, soft drink being clear there would be a lot of cud in the bottle.

Of course in modern society digesting plants more efficiently is bad. More energy makes you fatter and roughage is good.