AFAICT, the genetic inference is simply that -- the inference any biologist would make based on the what seems to be invariant behavior (namely that most people who try to diet fail). But the "n is tiny" argument that you make above about the stats is much more of an objection to a biological argument that it is to a social one. There is zero justification to consider diet failure a biological invariant if all you have is data on one population in one time period -- it doesn't matter how many people are in that population.
.........................
No doubt you're right.
This is why, right after questioning the stats I wrote:
"But let's assume it is true and see where that takes us."
Because really, I'm much more interested in the biological and social questions than I am statistics which are useful and revealing but not my thing (I feel the same way about say, the ballet - lovely and enriching and I love to go but I'd much rather spend an evening working on the Tesla coil).
I did find this statement of yours intriguing:
Genetics operates by making us more or less sensitive to environmental stimulus (using environment here to cover every realm from the micro-cellular to the macro-ecological). It does not stop us from being influenced by the environment. Including the social environment, which is one of the most important. Including in a long term, one way direction, like getting fatter. (Or taller). And it doesn't at all proscribe what can be done by willpower. It only determines what is easier and what is harder -- and part of how much.
........
Yes the nature/nurture thing should be as dead as Caesar.
But beyond that I'm fascinated by your use (perhaps merely convenient) of the word "willpower". What a pity something as fundamental as eating must now - many of us feel - be treated as a Herculean test of our will and, it's quietly implied, character.
.d.