winjim
Smash the cistern
It's important to note, amidst all this talk of choices, that some people are more 'hard wired' than others. There are genetic and epigenetic factors at work. For example, a fetus which is small for gestational age may initiate a starvation response meaning that after birth and for the rest of their life, they have a greater propensity to eat as much as they can and store the energy as fat. This has an effect on not only their weight but also morbidities such as CV disease, diabetes etc.The bottom line is, Humans are hardwired to fill up when there is plentiful food in order to survive the famine that's round the corner - the legacy of our hunter-gatherer past. Except in this day and age, and certainly in the western world, famine in incredibly unlikely. But our bodies still want us to eat as much as possible - just in case.
And... here's the interesting bit, the starvation response is achieved by DNA methylation in utero, silencing various genes and activating others. This methylation is itself heritable, meaning that the starvation response is passed down through the generations. So if your grandmother had a small baby, it is possible that you and your children will have that epigenetic alteration and be prone to overeating and obesity.
Then you have the effect of particularly fat and sugar combinations which are not found 'naturally', triggering hormonal responses which we've not properly adapted to, be it addictive pleasure responses or simply messing with our sense of satiety. We haven't evolved to eat this sort of modern diet and it does weird things to our brain.
I'm sure there's more, that's all just basic biology before we even get into psychological and socioeconomic issues. So anybody who claims that it's a 'simple' matter of 'choice' needs to think about their own circumstances and how they may differ from others not just at a superficial level but also at a deeper level, possibly going back generations.
Yes I have just taken a nutrition exam and yes I think I did alright in it, thanks for asking.