There's a phrase about a person "being what they eat" and I think it'd be great if that was literally true. Imagine all those big Macs, chocolate bars and other junk foods there would be walking around the place; it might teach them a lesson.
Instead, it refers to a person's health being dependent upon how they eat. Eat badly and a person's health will reflect that or eat healthily and a person is likely to be healthy generally. In my experience, those who focus on healthy eating often have a mind to keeping physically active and have a good emotional and mental health as well. Those who do not tend to be the opposite.
Unfortunately, it's usually those with lower incomes who eat most badly. I'm not sure if that's simply because junk foods are cheaper because I do not think they are. I'm not sure if it's an education thing, learned habits from parents for instance, laziness, or if it's an intelligence thing. I'm sure there's multiple reasons with discipline and effort being among them. It takes effort to make buy fresh produce and make healthy meals and it takes discipline to stay away from sugary and carbohydrate foods that often taste so good. I'm no expert though, I'm just speaking generally.
I'm not wealthy, but I try to eat fresh produce, whole foods, and it's often time consuming and an effort but I know what the result will be from heating badly. Obesity, health issues, lack of energy and movement and usually an early grave.
We all have the choice to eat healthily and to exercise or not. It doesn't mean we won't have trouble along the way if we do but I believe life should be lived as best as possible and if eating well and staying active helps us enjoy life more then why wouldn't we do that?