Admittedly a minor point of interest, but the last famine in England happened in 1623 and was local to an area called Westmorland [0]. That was 150 years before the Industrial Revolution, so the 10% figure might not be very reliable.
England was the first nation to escape from famine. A national market began to take shape shortly after the civil war, and the national market transformed traditional famine into a question of high prices. Jethro Tull began his experiments in 1701, and Charles Townsend began taking notes about fertilizer shortly afterwards, and when the public became aware of their work, the Agricultural Revolution began, and then, shortly afterwards, the Industrial Revolution. But obviously, most of the world continued to experience famine into the 1900s.
There is some evidence that there are health benefits that are specific to the fasting mode. This has mostly been studied in the context of chemotherapy, where fasting can protect against some of the side-effects of chemotherapy:
https://pmc.ncbi.nlm.nih.gov/articles/PMC5870384/
Most of this has only been studied in animals, not humans, but in animals the results were clear:
"Fasting before chemotherapy (CT) was shown to protect healthy cells from treatment toxicity by reducing the expression of some oncogenes, such as RAS and the AKT signaling pathway [2]. This reduction is mediated by the decrease of circulating insulin-like growth factor 1 (IGF-1) and glucose. In addition, starvation and calorie restriction activate other oncogenes in cancer cells, induce autophagy, and decrease cellular growth rates while increasing sensitivity to antimitotic drugs [2]."
If we assume that we have been shaped by millions of years of frequent famine, then our evolution has been shaped by famine. It is possible that our immune system simply makes the assumption that we will soon face famine, and therefore some important tasks, such as extreme autophagy, are normally postponed till the famine arrives. However, in the modern era the famine never arrives, and so we may have to induce it by artificial means.
I have experimented with very long fasts. My longest fast ever was in September of 2015 when I managed to go 12 straight days on nothing but water.
Obviously, any health benefits from that incident might have been psychosomatic, since I was expecting health benefits. But all the same, I did find some of the health benefits to be shocking and completely unexpected. Since at least 1995, and possibly 1990, I had a mole on my skin on my left arm. I wasn't worried about it, so I simply ignored it. I had it on my arm at least 20 years, maybe 25 years. I recall one morning in November of 2015 when I was in my kitchen, making breakfast, and I reached over to pour myself some coffee, and of course my arm was in my field of vision, and after a moment of thinking something was different, it occurred to me that the mole was gone. It had been there at least 20 years, and then it disappeared, at some point during the weeks after I had done the 12 day fast. I don't know when it disappeared, it just slowly faded away at some point between September and November. There was no remaining sign of it on my arm.
Again, that might have been purely psychosomatic, but it was interesting.