Comment by ellyagg | Hacker News Reader

Comment by ellyagg | Hacker News Reader

There's a totally different way to live that also has mounting evidence, and it's a way that sounds a lot more satisfying to me.

For awhile now, the "obesity paradox" has been a thing, where segments of the population who are a little heavier than one would expect actually have the best all-cause mortality rates.

Recently there's been some pushback on this "paradox", but the one I want to call attention to is here:

http://annals.org/aim/article/2499472/relationship-among-bod...

The problem with the obesity paradox is that it's been based on the flawed BMI. In this study, they actually did DEXA scans of elderly women's body fat percentage, and those with the highest BMI and lowest body fat percentage had the best all-cause mortality rates.

This suggests plenty of calories plus strength training is in the running for a longevity lifestyle. This makes sense intuitively and if one is familiar with the panoply of beneficial physiological effects from exercise on the human body. And, it would not come as a shock to find that increased strength from greater muscle improves, e.g., balance and coordination to prevent accidents in the elderly, nor that increased muscle mass provides a protective tissue reserve for fighting disease without the concomitant downsides of adipose.

Don't be faked out by BMI; it's no different from the Dow Jones Index (something easy to calculate with pen and paper, or in your head), that gives you a low-resolution signal at best. If you have a BMI of 50 (or 16) you have problems, but you already knew that.

It's bizarre that people worship it, but then again, simplicity has always beat having to think.

Very nice analogy. What's the equivalent of the S&P 500 then? :-)

You can be a bit healthier by just doing a whole variety of things and accepting the average, than by letting an expert choose what things you should do. ;-)

The equivalent is probably a 2D DXA scan with body composition report. Supposedly it can measure the amount of bone, muscle, and fat in your body to within 1% of actual values. Those scans are widely available for <$50.

BMI is still a pretty good proxy measurement. There's a very high correlation between BMI and body fat content. People like to complain that BMI is useless because a few weightlifters show up as "obese" but those are so rare as to be statistically insignificant.

> People like to complain that BMI is useless because a few weightlifters show up as "obese" but those are so rare as to be statistically insignificant.

A good explanation I saw is that if you care what your BMI is you probably aren't a weightlifter

IIRC the largest problem comes from BMI under-reporting high body fat.

Good thing the post you're replying to isn't worshipping it and in fact is based on a study using DEXA scans instead!

> It's bizarre that people worship it, but then again, simplicity has always beat having to think.

It's pretty good over populations, and is pretty good even on lots of individuals. Body fat percentage and lean mass might be better but they're much harder and more expensive to measure (particularly accurately).

This jibes with my own pet theory for longevity. Our bodies evolved in much more demanding conditions than we have now. Wild temperature swings, strenuous work, etc. I think a lot of current diseases are caused by the systems the body developed to deal with these things that now have nothing to do, like an unloaded motor spinning out of control.

> Our bodies evolved in much more demanding conditions than we have now.

Why do you think how our body evolved is related to longevity ?

Are you asking why longevity is a desirable trait?

Evolutionary longevity, beyond a point, is not something that necessarily gets selected for.

I'm asking how selection could influence a trait that manifests itself past reproductive age.

Long juvenile period. A 10yo human child with living parents has a greater chance of surviving to breeding age than the same aged child with dead ones.

Also, a reproductive pair with living post reproductive (but still not decrepit) parents can breed at a higher rate as they are can delegate some childcare to them.

Children might have better likelihood of eventual reproduction if their parents are in good health as the parents raise their children during and past the parent's reproductive age. I could even imagine present and healthy grandparents having an influence on the reproductive probabilistic success/failure of their grandchildren.

People continue to influence their children long after they stop reproducing. Genes that help you children have more children are selected for, so something like a gene that keeps you alive long enough to care for your grandchildren seems plausible.

Although there are also clear costs to this, and as you look at longer timescales the benefits become less pronounced.

I'd at least say I don't see a strong evolutionary pressure for extended lifespans.

> I think a lot of current diseases are caused by the systems the body developed to deal with these things that now have nothing to do, like an unloaded motor spinning out of control.

"This suggests plenty of calories plus strength training is in the running for a longevity lifestyle."

Why not both ?

Relatively high calorie diet, over the long run, to support strength training and a high level of exercise ... but regular (weekly ? twice-weekly ?) fasting to partake in what appear to be the benefits of forcing your body to change gears and clean house (so to speak).

You can have a relatively high calorie diet measured over the course of a week or a month while still fasting regularly.

In this context: because the article is about total calorie consumption, not timing.

The article does seem to be about total calorie consumption so fasting once a month or year does not seem to be beneficial as long as total calories remain the same.

What doesn't make sense to me is that exercise is known to be healthy but it will always lead to an increase in calorie consumption especially cardiovascular. When you exercise you are expending more energy so that means you need to take in more energy or calories.

> This suggests plenty of calories plus strength training is in the running for a longevity lifestyle.

But will strength training not wear out the joints?

Strengthening your muscles can relieve strain on joints.

For example strengthening your thighs reduces stresses on your knees. At least according to my orthopaedic specialist.

This! My wife had chronic knee pain that no one could figure out given her relatively youthful age. A smart trainer spotted that her leg muscles were very, very weak. She strengthened them and now has no knee pain - and in fact is running about 20-25m per week where before she assumed she'd never run again.

Well, I happen to have personal experience here. I had pain on the outside of my right knee for a few years. I also had clicking in my knees whenever I would squat down, ever since I was a teen. One day, I did an hour of Bulgarian split squats[1], which is a one leg exercise -- I did it with no weight. The next day my knee pain was essentially gone. One day!

It turns out, after reading up on it, unilateral leg strength is important for knee health. The right muscles being strong and coordinated takes stress off the tendons, ligaments, and cartilage that support the knee. Doing one leg squats teaches and trains your glutes to balance and stabilize your body on one leg.

[1] For an unrelated experiement.

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