[yaakov34]

There is also this commonly held notion that if you "live right", with healthy habits, food, and exercise, you will live to 98 in perfect health, and probably die of an instant heart attack while in bed with a young lover. It's of course true that obesity and lack of exercise increase health risks at all ages, but that risk was never going to be 0. The notion that I mentioned basically makes health problems into a morality play. I've even seen people get angry at the fact that statins can reduce heart disease risk in an "unearned" way - they can't accept that. The fact is that blood vessels and everything else lose function with increasing age, at a different rate for different people.

[henrikschroder]

> There is also this commonly held notion that if you "live right"

One of humanity's greatest questions is "Why do bad things happen to good people?"

The inconvenient truth, of course, is that the universe is cold and uncaring, and random chance and statistics means that bad things will happen.

But we humans hate that answer. We crave structure, patterns, cause and effect, order. Why did flooding destroy a city? You must have angered the gods with your sinful ways! There we go. Cause and effect. Peace of mind. Rules have been created. The universe makes sense again.

Why do young people get cancer? They ate the wrong food! They didn't exercise enough! They didn't fight the cancer! They did this, they didn't that. Cause and effect. They broke the rules. And as long as I don't break the rules, bad things will not happen to me. I will never anger the gods, eat the wrong food, or forget to exercise, and those who do, they're immoral and deserve the bad things that happen to them!

And that is why this is a morality play.

[rmchugh]

I've seen this described as the Just World fallacy. It's pretty engrained in our culture, with supposed religious mechanisms being gradually supplanted by pop scientific theories.

[kornish]

Here's a well-researched and well-phrased blog post on the Just World Fallacy that you (and grandparent post) may find interesting: https://youarenotsosmart.com/2010/06/07/the-just-world-falla...

[1123581321]

It is a fact that lifestyle affects likelihood and progression of heart disease. Rare cases that end life early for genetic reasons do not change this. It is unfortunate that some people assume all early heart problems are avoidable, but only because sharing an opinion is unnecessary, not because the assumption is likely wrong.

The morality of not taking care of oneself is subjective, of course.

Edit: I should say I lost a sibling to incurable cancer at a young age. I have heard no end of useless advice about her diet, special almonds, clinics, etc. So I strongly believe in not sharing advice that helps a majority when talking to a particular person, even though I know there are ways to live that reduce likelihood of some cancers.

[yaakov34]

It is a fact that the effect exists, but I think that you are also victim to the popular idea that this effect is extremely powerful or even overwhelming, making "taking care of yourself" a powerful morality tale. Here is a quote from a large study:

"having a BMI between 30 and 35 shortened life by an average of 0–1 years, having a BMI between 35 and 40 shortened life by 1–3 years, and having a BMI above 40 shortened life by 1–7 years"

(This is easily googlable, I don't want to turn this message into a journal article)

Note that the error bars on the effect are quite large (1 to 7 years even for extreme obesity). Now it's true that a lot of things hide in an "average", and there is a lot to discuss here, and I am definitely not discouraging anybody from acquiring healthy habits and lifestyle, but... it's just not a simple story of reward for virtue and punishment for sins. Genetic factors which we have no control over probably have a greater effect. Which is not a story that people want to hear.

[1123581321]

Sure, I understand what you are saying. Those are actually significant findings, though. Keep in mind how good we are at keeping people with progressed heart disease alive. The relatively few years' reduction in lifespan masks, in my cases, early onset of heart disease and years of expensive emergency response, frequent hospitalization, transplants, reduced quality of life, and so on. Better is to look at large meta studies about bmi, smoking, diet, and physical activity as they affect rates of disease as well as mortality. I quickly searched and found many results.

Respectfully, I haven't said anything about living until a very old age. I am only talking about a few diseases and I understand there are a lot of ways to die. I have also said the morality of not trying to extend lifespan is subjective.

[treehau5]

What about going the other way? how does having a BMI of 25 to 30, 20 to 25, 15 to 20 work?

[yaakov34]

The same study says that low BMI is also associated with lower lifespan, and the statistically optimum BMI for white people is 23 to 25 (there are racial differences in all the numbers, which I think also challenges the idea of assigning moral qualities to them).

However, I don't know if I would give too much thought to the effect for low BMI - it could just be that people with extremely low BMI tend to have some disease process which causes that; only a small minority of them are rail-thin athletes. For high and extremely high BMI, there are known causal mechanisms for disease, so it's a different story.

[shanacarp]

We have a huge environment we live in, plus we shape are environment to an extraordinary high degree. Furthermore, we're actually quite sensitive as organisms to those changes, including in ways where it's only now coming out in some cases because our previous equipment wasn't sensitive enough to register what was happening. We also actually know very little about genetics, genomics, and epigenetic despite posturing that we do. That's why the error bars are big

Fundamentally, actually shrinking that error bar for many diseases is one of the biggest hard science and math problems of the future.

It's going to be so exciting!