For myself the largest impact would have to be diet improvements, just like for most people. But, in general I want to be able to be much more preventative inst

For myself the largest impact would have to be diet improvements, just like for most people. But, in general I want to be able to be much more preventative instead of reactive. I don't want to get diagnosed with atherosclerosis or diabetes in 10 years, I want to prevent the onset of them as best as I can now. But, to try to provide a more helpful answer, here is two examples of things I do now, with much more detail: 1) I get a lot of (mostly blood) tests, and work to optimize them past 'making sure they are okay'. A lot of basic tests can be kind of pass or fail, like "do you have enough iron?" or "do you have enough vitamins?". But, a lot of other tests are less quantized, and have a lot of room for improvement past just being in the standard range, which does not mean you are optimal, just not doing terribly. A good example for this is an advanced lipid panel, triglycerides, blood pressure, and insulin resistance. Just getting results of "you probably aren't going to have a cardiac event or get diabetes" is good, but they can be optimized much more than this to reduce your long-term probability of many problems to as low as possible. It's also fun to find out the diverse array of other tests you can get to learn more about yourself, and potentially optimize. Nerdy people generally like optimizing things, and having numbers to attach to how well you are doing makes this a lot more alluring, at least for me. 2) A lot of more speculative research on different dietary (whether food, supplements, or drugs) changes that I can make for hope of long-term noticeable improvements. More common examples here might be things like magnesium or Vitamin D, but there's countless rabbit holes you can go down of many, much more interesting examples (For example, metformin, rapamycin, and many many others). The reason I don't provide a list is mostly because everyone is very different and has different goals, and also because I'm not a fan of the (mostly terrible) supplements industry as a whole. But just because so many popular products use junk science and scam consumers, doesn't mean there are many real gems out there.