> Well the driving part doesn't matter, the thing we care about is how hard it is for someone to get to a place with affordable healthy food, however they get there.

Can’t be much harder than it was 100 years ago, when everyone was extremely poor by today standards, and visiting a grocery store was often a whole day trip, no? Obesity didn’t seem to have been a problem at that time. Seems like it really is not about lack of access to affordable healthy food, which today, by any historical standard, is very easy even in most deprived places in US.

> If it's an urban area where a significant portion of people don't have easy access to a car, then you wouldn't look at driving times.

Most poor people in urban areas do have easy access to a car. Cars are extremely cheap in US, poor Americans enjoy high consumption levels by global standards, which typically entails access to cars.

In any case, for this to support your argument, which that lack of access to affordable healthy food drives obesity, we’d need to have that in urban areas, carless people are significantly more obese than people with cars. To reiterate, your argument is that drivers are less obese than people who are too poor to drive. Is it actually the case? I seriously doubt it, but you’re welcome to show data supporting your theory.

> These are called food deserts, and there is a ton of research on them. From what I've read there is not a direct line between food deserts and higher obesity rates, but it is a relevant factor, especially when abundant dollar stores and fast food places are offering cheaper and more accessible food than the nearest grocery stores (if there are any).

Yes, I’ve heard about this stuff, and most of this stuff is highly motivated logic with extremely meager support in facts. Even you admit that the whole food desert thing has little actual observed causal impact on obesity rates. Instead, the poor just go to convenience stores and buy crap, and they do this even if they have healthy options easily available (this is true, because otherwise you’d see clear correlation that people close to grocery stores with cheap and healthy food are not obese, which you don’t).

Here, let me propose an alternative theory, which matches facts on the ground much better: many poor people in US are low in conscientiousness and long term thinking, and so instead of engaging in relatively complex activity of buying bulk staples and cooking simple and healthy meals, prefer to spend extra for convenience of unhealthy foods from dollar stores and fast food. This is possible, because their “poverty” is not an absolute level, but rather relative measure. By this I mean the fact that by global standard, American poor enjoy quite high consumption levels, so they can easily afford these unhealthy habits. Making healthy food easier to obtain for them will, as you admit, not change much, because people will just not take advantage of it, instead preferring easy and unhealthy food instead. Instead, what you’d need to do is to immiserate them even more by either taking away convenient and unhealthy options nearby, or reduce their purchasing power to make them unaffordable. This is, of course, seen as immoral, so it will not happen.