As far as I know, during Ramadan you're only allowed to eat and drink when it's dark, which is more like a pretty extreme version of intermittent fasting (depending on daylight duration).

And the Iftar tradition basically to break fast with a giant meal each sun downn. Makes it seem even more extreme up and down.

yes depending on your daylight, approximately, it takes between 13 and 18 hours. I am fasting one month a year, more than 10 years, and I can’t call extreme, it’s more like need

I wonder whether anyone has studied the weight (or even gut bacteria) of observant muslims compared to the population at large.

Ramadan is for one month and you'd be hard pressed to find a lot of obese people seeing as much of the Islamic world is not only still developing or war torn, but also very poor. You would have to do a study of ones closer to normal western standards of a daily diet to get a better control. Otherwise of course the weight of a country where you work 12-16 hours a day and eat 1600 calories max is going to be full of thin, lightweight individuals. The fact that they fast one month out of the year would have no large scale effect. Also, during Ramadan, you can eat/drink before and after sunset/sunrise. So if you gorge, your stomach size increases and then naturally adjusts to the schedule so you whole digestive system sustains itself over a longer period of time as opposed to churning calories as they are incurred.

Edit: my comments on the Islamic world were not a slight. It's a factor that should heavily be taken into consideration when comparing them against Western nations that do not have even remotely the same medical problems in regards to weight.

Kuwait, Qatar, and Saudi Arabia have some of the highest obesity rates in the world.

https://data.worldobesity.org/rankings/

You said: "you'd be hard pressed to find a lot of obese people". ~41 million isn't enough?

>...obese people seeing as much of the Islamic world...

Thanks for cutting of a very important part of my actual statement to paint me as some ignorant moron.

Also, 41 million are not obese. Now your articulating another data point to suit your narrative. I'm talking in the grand scheme. My argument was never "hur dur there aren't obese people in the Islamic world!"

The US alone has 30-45%[0] obesity among 300 million meaning. The Islamic world has 1.8 billion. Assuming we just use the same statistic on the high end of the American side for the three countries you named, that is still only 18 million. The US has 96 million on the low end. If you factor what I actually said, the Islamic world, it's again, an even smaller percentage than the 1.25% I quoted earlier.

[0]https://www.cdc.gov/nchs/products/databriefs/db360.htm

There wasn't really a good place to cut the quote, so I trusted people to follow the thread. I have no intent to paint you as anything and don't think a reasonable reader would be convinced you're ignorant from what I replied with.

I have no real narrative to speak of in this conversation either, my only intent was to point out why I thought the great-grand-parent post had included those data points.

People binge on sugary drinks when they break the fast then stay up all night eating meat and rice. This doesn't do good things for insulin resistance.

ROCOR's Lenten fast would make a more interesting study.