That’s interersting RobTuck. I am not sure I understand the thrust of your post, it’s possible that I don’t, as it’s just not very clear (to me 
). I’m gathering that you gradually evolved your thinking from an emphasis on supplements and geroprotective interventions (medications etc.) toward the primary focus being on getting to optimal healthspan and lifespan through lifestyle interventions first and foremost - exercise + diet(?). Again, if I misunderstood, I apologize.
In any case, regardless of whether you hold that view, it’s a view that’s quite prevalent in health focused circles. There are quite a few such advocates on this site (I’m not saying you are one of them!), the ethos can be summed up as “accomplish all your health goals, healthspan and lifespan through lifestyle efforts, without drugs if you can help it”. It’s part of what I call the “naturalistic fallacy”, which sees “nature” as providing optimal solutions and human intervention can only degrade the result (again - not saying that’s you, RobTuck!).
I think it’s a view worth examining. As happens, my journey has been in the opposite direction: starting out in my youth as holding that lifestyle adjustments should be the primary approach with supplements, drugs and other interventions to be complementary, to my present view that while lifestyle optimization is a good first step, it is liable to be a very minor part of true healthspan/lifespan extension, and one should really focus on meds, supps and other interventions.
In practical terms: I don’t see any reason to go much beyond avoiding destructive lifestyle choices. So, for example, in exercise, step #1 would be avoiding sedentary behavior. You can hit 80%-90% of exercise health/longevity benefits with a relatively modest investment of time and effort. I see zero reason to pour massive amounts of time into exercise that gets you asymptotically closer to “perfect”. The squeeze is just not worth the juice. Looking at the evidence, my conclusion is that the last paltry few percetage points are bought at an unreasonably great investment in time and effort. If you enjoy exercise - fine, you do it because it enhances your QOL, and better health is a byproduct, in which case it is not an “investment” as much as the whole point of it. But I - like many others - don’t enjoy exercise and see any investment of time and effort into it, as an opportunity cost - I’d rather be doing something else, it’s a question of QOL. I exercise to live, not the other way around. Same with diet. Luckily(?) for me I naturally enjoy an extremely healthy diet, it makes me feel good and I find pleasure in it - but if I had the same predisposition as toward exercise, i.e. I enjoyed SAD or were a fast-food addict, I’d have the same attitude - just get the big picture OK, a roughly healthy diet, without the extremes of self-deprivation.
So the bottom line, I believe that doing mostly OK in the basics of lifestyle gets you 80%-90% of optimal health, and if you were to dedicate yourself to a fanatical optimization regimen, you’d barely sqeeze out enough extra healthspan/lifespan to notice. In an analogy I’ve given once before - if your aim is to move between Los Angeles and NY as fast as possible, running will only take you so far, you can run a little faster with extensive training, but even elite level athletes will only make marginal progress - you need a horse, a car, an airplane, a rocket and other tools of civilization. So, my attitude is - training enough to being able to run at a reasonable and comfortable speed is only going to take you so far, for real speed, I’ll have to focus on the tools of civilization. Thus my motivation to squeeze out another 2% of speed from my running at the cost of spending 20% of my lifetime exercising is exactly zero.
And that’s my feeling about the balance between lifestyle vs medical interventions. Do enough with lifestyle to not set yourself back, but your real gains are only going to come from science. So an inversion of the naturalist - get your meds and geroscientific interventions in order and for lifestyle just make sure you’re not being destructive.
Real life examples of interventions would be: a healthy lifestyle is good for the eyes. But no matter how many carrots and cups of kale you consume, and how many hours you spend running in the mountains, age will degrade your eyes at almost the same rate as someone who has just a reasonable diet and exercise program. You will develop cataracts, and your lenses will become stiff, your vision less sharp and so on. Meanwile, you can replace your lenses with IOL surgery and have a vision at 90 years old that most 20 year old would envy. Running vs a rocket ride.
It makes no sense to harden your body against blows by rigorous exercise (MMA fighters and bone rolling exercises), if you have access to guards - helmets, gloves, shinguards etc. The latter will be infinitely more protective than any amount of hardening exercise.
Here is a thought provoking statement by Brian Kennedy in an interview on Matt Kaeberlein’s podcast. In essence, when they looked through NHANES data (confirmed by UK Biobank data), they discovered an interesting phenomenon: there were those people who naturally had their key biomarkers within normative range, just by themselves (perhaps also assisted by excellent diet and exercise etc.), and then there were those who had their biomarkers brought to within “normal” range through certain medications (lipid, glucose, BP etc.), i.e., they were originally out of range (in “inferior” health) and then they matched the biomarkers of the “naturalists” only thanks to modern medications. Well, it transpired that the folks who got there through medications had ultimately better outcomes, and were biologically younger! This shows the power of medications, and thinking about it, perhaps it’s not surprising at all. Here’s the discussion, starting at minute 12:19:
This may seem like a paradox, but it’s not, if you think about it. For many people (me included), no amount of healthy living diet and exercise can get my lipids to within norm. Same (for me) for blood glucose. Blood pressure (me again). My genetic predisposition and aging prevents that. And for others, they can reach their biomarker targets through lifestyle means, but sometimes have to take heroic measures. But meds can get me there - and better. I can probably get better lipid numbers through medication than someone else can with no matter how good a lifestyle. Because while the lifestyle guy is running their guts out, he’s still on a long journey and I can zip past him with ease in my Lambo.
What’s notable is that these suboptimal guys got to a better place with meds than the optimal guys with just lifestyle. So you can start off with OK diet and OK exercise and still outpace the guy with optimal diet and exercise just with the use of meds.
There are of course more powerful agents that we hope will give us a much bigger boost than statins, ARBs, SGLT2i, etc. - like rapamycin. Because no matter how good the diet and lifestyle of those mice in the ITP, there was no way they could match rapamycin.
We are gambling that the same holds true for humans.
And therefore my approach is to say - I’ll exercise “enough”, and spend my time living my life to my satisfaction. I’ll eat healthily “enough”, but not worry about the occasional cake or glass of wine. I don’t need to be an ascetic lifestyle purist or some kind of monk, priest of healthy living. I can just be “OK”. My real focus is - and in my view should be - all those other things, the meds, the supps, the bionics, the Lambo, and the rocket. Only the latter will make the real difference.
