which humans did for millenia without getting too damn fat until about the 1990s
That’s the really mysterious bit to me.
I don’t think excessive quantities are likely to be the problem, though. I read a caloric breakdown once of the lifestyle of a 10th-century Scandinavian farmer; the energy requirements turn out to be absurd by modern standards, something like six thousand kcal just to stay upright at the end of the day in peak season. (Winter life was a bit more sedentary, but still strenuous by modern standards.) If you’re consuming that much food regularly, an extra five hundred kcal here or there is a rounding error; it’s implausible that everyone back then just happened to manage their consumption to within a few percent. Nor was the civilization as a whole calorie-bound, as best we can tell. But judging from skeletal evidence, they didn’t suffer from many of the diseases of civilization that we do.
The obvious diff here is exertion, but the nutritional literature I’ve read tends to downplay its role. Or you could blame portion sizes relative to exertion, but larger portions are only fattening because of the excess calories, which brings us back to the original mystery. So either some novel aspect of the post-1900 diet is making modern Westerners fat, or the archaeology or the nutritional science is wrong, or I’m missing a step. And I don’t think I’m missing a step.
If I had to venture a guess, I might blame lots of simple sugars in the modern diet—honey was the only sweetener available for most of human history, and it was rare and expensive. But that’s extremely tentative and feels a little glib.
This article contains links to several peer-reviewed research studies on the matter.
[e]xamined samples collectively consisting of over 20,000 animals from 24 populations of animals representing eight species living with or around humans in industrialized societies. In all populations, the estimated coefficient for the trend of body weight over time was positive (i.e. increasing). Surprisingly, we find that over the past several decades, average mid-life body weights have risen among primates and rodents living in research colonies, as well as among feral rodents and domestic dogs and cats.
That’s the really mysterious bit to me.
I don’t think excessive quantities are likely to be the problem, though. I read a caloric breakdown once of the lifestyle of a 10th-century Scandinavian farmer; the energy requirements turn out to be absurd by modern standards, something like six thousand kcal just to stay upright at the end of the day in peak season. (Winter life was a bit more sedentary, but still strenuous by modern standards.) If you’re consuming that much food regularly, an extra five hundred kcal here or there is a rounding error; it’s implausible that everyone back then just happened to manage their consumption to within a few percent. Nor was the civilization as a whole calorie-bound, as best we can tell. But judging from skeletal evidence, they didn’t suffer from many of the diseases of civilization that we do.
The obvious diff here is exertion, but the nutritional literature I’ve read tends to downplay its role. Or you could blame portion sizes relative to exertion, but larger portions are only fattening because of the excess calories, which brings us back to the original mystery. So either some novel aspect of the post-1900 diet is making modern Westerners fat, or the archaeology or the nutritional science is wrong, or I’m missing a step. And I don’t think I’m missing a step.
If I had to venture a guess, I might blame lots of simple sugars in the modern diet—honey was the only sweetener available for most of human history, and it was rare and expensive. But that’s extremely tentative and feels a little glib.
The really creepy part? Whatever it is, it’s making Western animals fat. Including the ones that aren’t fed scraps of human food.
That is remarkably interesting-if-true. Data?
This article contains links to several peer-reviewed research studies on the matter.