Just jumping here on this topic because I've been reading up and been super into fasting the last couple of years
I find it fascinating, BUT just to be clear it is NOT about starving yourself, but more about healing your body and changing our habit of consuming food constantly and mindlessly! (Like, 24/7, no breaks, snack after snack) Which historically, humans never did until after the 1970's or so.
Also fasting is strictly not recommended for kids, adolescents, pregnant and breastfeeding women, people with any serious illnesses, malnourished/underweight and people with EDs.
But basically the point is that nowadays we have food available to us everywhere, at all times. We are speaking of the wealthy, developed, first-world countries and not of any place suffering from food scarcity of course. But in the past people lived by the principle of "fasting and feasting". There were periods of times abundant with different kinds of foods and times when you had very little and had to save your resources.
The most interesting thing to me is and you only realize it when you hear it from all these researchers which is that humans wouldn't have survived if we didn't have the ability to go a day without food. Like, you don't die right when you sleep or when you have to go out in the morning and find something to eat first (hunt, colllect and prepare food before refrigerators exitsted).
I personally usually skip breakfast, too and usually fast for 16-18 (sometimes 20) hours. Which is not extreme at all, most people are just used to eating all day, late into the night and having snacks available constantly which never gives your digestive system a longer break.
Even if you normally consume food between 9 am and 5 pm, that gives you a 16 hour break between your last meal in the evening and your breakfast the next day, which is perfect. Some people can't even go 12 hours without snacking on some chips, poopcorn or choccy first, because it is such a strong habit. In the previous century people used to eat much smaller portions and usually have three main meals a day and before fast-food and food-deliveries were even possible the whole preparation of food would obviuosly take more time. The convenient, consumerist lifestyle of many in our society today is very different.