So, I’m a big fan of Dr. Gregor “How not to die“, which is essentially how to fight the big killers of our day with a plant based diet. The premise is rather plausible. Whether you have a cultural aversion or proclivity towards plant based diets or not, the advice for heart disease, diabetes, kidney failure and cancer are all very similar- as if they were one disease. In Japan they call it metabo. The advices you get tend to be don’t smoke, drink booze or eat sugar/white carbohydrates. Eat a wide variety of plants, including whole grains, nuts, seeds, etc.
Now if you survive those on average you’ll live ~13 years longer. In other words, if you follow the protocol right, you die in your 90s instead of somewhere between your 60s and low 80s. To live longer than that without a protocol, you need parents you gave you an unusually excellent genetic structure.
So I now follow such a protocol and I’m reading up on what is going to happen. I should now avoid most typical health crises. [On a side note, I suspect that some countries full of bad habits like smoking and drinking live longer because their public health system helps people get past crises, e.g. surviving heart attacks through better CPR instead of better diet and exercise!] But how is the quality of life doing? Obviously no one wants 13 extra years of Alzheimer’s and disability. [I'm not talking about quality of life in the sense of the joys of smoking, getting drunk and eating meat at every meal- I'm okay with skipping those.]
There is some evidence that a plant based diet will help prevent some version of dementia, i.e. those cause by excessive metals (often derived from animal products), vascular dementias (where your brain vessels fail just like your heart vessels fail in heart disease).
Improving late life health starts to move us into some areas other than plant based diet.
Fasting/Calorie reduction strategies. This TED talk summarized the Fasting Mimicking Diet as a way to trigger alternate metabolic pathways that encourage old cells to die, be replace by new stem-cell derived cells. It appears to be a built-in means for all animals to respond to famine. Us humans can use it to trick our body into post-famine regeneration, except we use it to slow the rate of aging.
It is possible that plant based diets do the same thing as periodic fasting or lifetype fasting. A periodic fast denies everyone of possibly harmful foods, like candy and meat. [Thought experiment, what if our diet was cocaine, heroin and Taco Bell food-- any one week fast would give you body a chance to heal & you'd feel better, not because of fasting, but because you aren't eating cocaine and heroin and if that harm reduction was better than the benefit you got from Taco Bell food, you'd benefit from a fast. On the other hand, merely skipping healthy food might not have any useful benefit]
Also, a plant based diet will restrict your maximum intake of calories (plant based food is just less calorie dense and harder to binge on), restrict your methionine (a protein associated with accelerated aging), metals like copper & iron (insufficient and you are anemic, but too much and it accumulates in the brain- it is harder to overdose on plant based iron).
Heartbeat slowing. The best way to achieve this is by exercise. The downside is that any let up in your exercise protocol sends you back to your pre-exercise levels in about two weeks.
Sleep, Exercise. This is using a cardiovascular exercise program and extra sleep to fight dementia on the theory that dementia is caused when our brain can’t move waste out of our brains fast enough, because our circulation is bad or because we aren’t sleeping enough. Cerebral waste is only removed when your sleeping.
Falling. What kills 90 year olds, aside from dementia and the results of metabolic syndrome [i.e. diabetes, CHD, etc] is falling in the shower. So if you think you will live to 90 and want to live to 99, you need to have a strategy in place to avoid falling. I notice in my own behavior everyday cases where I do something risky and stumble, but I don’t fall because I got quick reflexes. And if I did fall, I’d just get a bruise. I have to break this bad habit now because when I’m 90, I’m probably going have fully ossified bad habits, like not holding on to rails, standing on one leg in the shower, etc.