Right, here it is. I checked back to the chapter with the studies conducted on identical twins, and the conclusion that "almost all of the differences in weight in a population are due to genetics". That's what I had in mind earlier on today, the key word being "a population". As in, the research mentions twins being reared apart, but is there some place to check what this "apart" was? I.e. if both were, said, in families of the same country and approximatively same social level, what does it say the most: that genetics are really so much more important, or that the difference wasn't so blatant because the environments themselves weren't that different?
For instance, if in a pair of identical twins, one was raised in a standard American family and the other in a traditional Japanese family (with traditional food, that is, not western food), would the second twin still be as overweight as the first one? I'm not sure the studies took that into account, but I didn't find many details either, so...
(I'm using the Japanese/Asian example, because it's not rare to see a person of Asian origin remain thin if on their traditional diet, but grow overweight if eating the western way. Cf. the author of the "Japanese women don't get fat" book, who did get fat when she switched to pizzas etc. during her studies. I guess she would be a person with a tendency to gain weight--genetics--but her normal environment wouldn't let this appear, sort of.)
I need to fully read that chapter again, anyway.
The last clear definite function of men — muscles aching to work, minds aching to create beyond the single need — this is man.
— John Steinbeck, The Grapes of Wrath —
Color Me Fit