> Obesity is largely a function of culture.

It relates to sugary and fatty food availability. So, yes it's cultural and can be improved by improved the system.

But, its root is the incapability of human beings on avoiding the 'temptation' of unhealthy food.

Asking people to stop eating too much and too bad does not work because our survival instincts tell us that to not eat when you can is stupid. So, changes in availability of unhealthy food are needed to improve the population health.

Your point does not invalidate my point, but both describe our society.

Sure, and I didn't mean to come across as obtuse, my point was that it's hard to find truly culture-insensitive aspects of the human experience.

Even the basics like our tastes in food, and what traits we find physically attractive, are steered by culture. You're right of course that ultimately we're wired to enjoy sugar, fat, and salt, in a way that works against our health when they are available in effectively limitless quantities.

I don't agree with Most of our behaviour is based on instinct. We allow perfect strangers into our homes to fix the plumbing. (Bruce Schneier wrote a great book about this kind of trust. [0]) A baby can learn to enjoy the company of a Malamute. Even our instinct to avoid being eaten by wolves, seems to be negotiable.

> changes in availability of unhealthy food are needed to improve the population health.

Agreed.

[0] https://www.schneier.com/books/liars_and_outliers/

>I don't agree with Most of our behaviour is based on instinct. We allow perfect strangers into our homes to fix the plumbing.

And we stay in the house to keep watch on them.

>A baby can learn to enjoy the company of a Malamute. Even our instinct to avoid being eaten by wolves,

You have to first establish that we have an instinct to avoid being eaten by wolves. And how that would work in humans that don't live where there are wolves for thousands of years.....

Hmmm. It's also a process of blind optimization on the part of companies that sell food. If they stumble into things that are addictive, that short-circuit the reward function in human appetite functions, they make more profit. Industrialization, marketing, high quality feedback mechanisms - they all add up to exploiting the human choice function.

Yes, industrialization of food is a function of culture. It's a tough one to fight against though, because marketing is also a culture generator; it needs constant oppositional effort.

If that is the case, then why are people in the same culture not equally fat?

Because it's not the only factor. Culture is an important factor but not the only one.

Income is another factor. Richer people had access to better food and better medical advice that pressures then to eat healthier.

Genetics are also another factor. Some people are better at accumulating fat than others.

That other elements does not remove cultural influence. You eat what is available to you in your region, what your parents cook, etc.

e.g. A country may tax sugary drinks to reduce availability and that reduces obesity in the country.