Proper sleep, a complete diet, minimizing stress (I'm personally biased towards meditation), intermittent fasting, and vigorous cardiovascular exercise complemented by strength training will by far have the most impact in maximizing your natural lifespan. You shouldn't look at doing anything else until you've at minimum mastered all of the listed items above. Nothing else will have as much outsized impact.
>Proper sleep, a complete diet, minimizing stress (I'm personally biased towards meditation), intermittent fasting, and vigorous cardiovascular exercise complemented by strength training Yes, but the problem is this is such a broad brush stroke. For example, most people who are chronically stressed will generally never be able to obtain relief. There is a common joke about abs being made in the kitchen not in the wei…
This really stood out to me. If this is how you feel, I strongly recommend trying out meditation. I at one point in my studies while in college felt the same, and it really is night versus day in being able to experience a life without constant stress/anxiety.
> The same for proper sleep. Its not just about 6-8 hours, its about quality. If you aren't getting quality sleep, most people don't have a solution.
Stress/anxiety from above is generally the most common cause of poor sleep. Fixing that will give quality sleep for the majority of people. The next thing to try is to check with your doctor whether you have sleep apnea as that's probably the second most common trigger. For some, sleep apnea is treatable with better sleeping posture and for others it will require more active work to resolve. A note that obesity is the most common cause of sleep apnea. The third most common cause is likely some kind of thyroid condition. More than that is probably going to be a case by case basis where you'll have to individually look at your genetic profile through something like SNPedia (https://www.snpedia.com/index.php/SNPedia) to try and pinpoint your underlying issue. Usually though, the first three things will cover the vast majority of people looking for better sleep.
> In other words the goal is to trigger the body to begin consuming/recycling dead cells and other cellular waste; however, this typically isn't triggered by time restricted eating, but requires longer periods of fasting (usually kicking in around after 20-24 hours of fasting
For most normal people, it's unrealistic to be able to do day fasts. That's why the 8/16 method is so popular. You'll still see benefits as you are incorrect that, there has to be a strict limit of precisely 20 hours to get beneficial effects. Autophagy like any other biological process in the body is a series of continuous interlinking upregulating and downregulating mechanisms that ensure homeostasis. Autophagy is always happening. It's just that the longer you fast, the more your body gets tilted towards consuming/recycling until of course you end up in starvation which is effectively just extreme autophagy.
> Finally "a complete diet", not only is there no general consensus what that is, you generally can't even have a conversation about diet without triggering a flame war.
A complete diet to the best of our knowledge, consists of getting enough macronutrients like protein, lipids, and carbohydrates in addition to an immense number of different micronutrients that while seemingly daunting in size are actually relatively easy to get enough of as long as you eat a diverse mixture of different foods. If that answer doesn't satisfy you, there have been many different studies and current ongoing ones as well to try and pinpoint all the essential trace nutrients the human body needs to survive. From the ones that we've been able to gather over the years, if you were to solely supplement yourself based on those listed, you'd probably be fine. Though it's likely that there would be some things missing.